Tomatoes are one of the most popular crops for home gardeners to grow. Their juicy red fruit adds flavor and nutrition to countless dishes and recipes. Typically, tomatoes are grown as warm-season annuals. This means they thrive during the warm summer but cannot withstand frost or freezing temperatures. However, with some extra protection, tomatoes can sometimes be successfully grown into the winter in milder climates. Here are tips on how to protect tomato plants from frost and extend the harvest.

Extending the Tomato Growing Season

Tomato plants are sensitive to cold conditions. Temperatures below 50°F slow growth and fruit production significantly. Hard frosts will damage and kill the plant. This makes tomatoes strictly a warm-weather crop in most regions. However, many gardeners like to extend the tomato harvest as long as possible in the fall before hard frosts arrive.

There are a few techniques that can help stretch out the growing season:

• Choose early-maturing tomato varieties. Cherry tomatoes and other small-fruited types often mature the quickest.
• Start seedlings indoors 6-8 weeks before your last expected frost date. Transplant them out as early as possible once the soil warms.
• Use season extension devices like cloches, row covers, greenhouses, or cold frames to protect plants in fall and allow the season to continue.
• Prune plants less and do not remove leaves to allow them to continue photosynthesizing as long as possible.
• Pick fruit early before a frost if necessary. Green tomatoes can be ripened indoors.
• Harvest green fruit before frost and make fried green tomatoes, salsa verde, or chutney.

With protection from frost, sensitive plants can often keep producing for several weeks longer than their normal season.

Protecting Tomato Plants From Frost

Tomatoes start to suffer damage when air temperatures dip to 32°F and below. A light frost will damage leaves and stems, but the plant may survive if the root system is protected from freezing. Hard or extended freezes will likely kill the entire plant above ground.

There are a few key ways to try and protect tomato plants from cold conditions:

Row Covers

Floating row covers are a great way to shield plants from frost. The material allows air, light, and water but traps heat around the plants. Make sure covers are in place before temperatures drop below 40°F or so. For best results, secure edges with weights or soil so cold air doesn’t enter from the sides. Plants can continue growing and fruiting under the covers. Row covers can typically provide 4-8°F of frost protection.

Agribon and Reemay are two common brands of row-cover fabrics. Look for ratings around 1.5-2 oz/yd weight material. Heavier versions block more heat and light but provide better frost protection. Make sure to ventilate if air temperature is high during the day.

Cloches and Cold Frames

Portable cloches or fixed cold frames serve a similar function to row covers. These structures are typically built from materials like glass or polycarbonate. They sit over the plants to create a greenhouse effect, trapping heat while still allowing light through. Cloches are smaller, individual covers placed over one plant. Cold frames are typically larger enclosures placed over an entire garden bed.

Venting cloches and cold frames is important during the day to avoid overheating. Look for models with automated openers. DIY options can work well, too. Use a thermometer inside the structure and ventilate once interior temps reach a certain level.

Wall O’ Water

Wall O’ Waters are simple but effective season-extending devices. They consist of plastic water-filled tubes that surround plants in a circular pattern. The water absorbs and holds heat from the daytime sun, releasing it slowly at night. This gentle warming of the air within the barrier can protect plants down to around 25°F. Wall O’ Waters come in sizes for both seedlings and mature plants. Make sure to refill with warm water as needed if freezing.

Hot Caps

Hot caps are waxed paper or plastic cone-shaped covers that fit over individual plants. The cone holds warm air around the plant, providing frost protection. They are reusable, though cheap enough to be disposable. Ensure to provide ventilation holes or remove them during the day if sunlight hits capped plants. Hot caps are less durable than other methods but work well for short-term cold snaps.

Heated Raised Beds

For vegetable growers with enough space, heated raised beds offer one of the most advanced protection systems. Heating cables are placed under the soil and regulated by a thermostat. This keeps the entire root zone frost-free. Meanwhile, the plants above ground remain unheated but survive through the protected roots. This allows production to continue even when air temperatures dip below normal growing conditions. It is one of the few ways tomatoes can successfully be grown through the winter in cold regions.

Winter Care for Outdoor Tomato Plants

In climates where frost comes late enough in the season, tomatoes may survive into early winter with protection. Plants will still need water and nutrients during this time, but growth and fruiting will be very slow. Here are tips for overwintering tomato plants:

• Stop pruning and allow the plants to grow naturally to maintain as much foliage as possible
• Provide supplemental lighting if sunlight drops below 10 hours per day
• Cover root zones with 8-12 inches of mulch to insulate the soil
• Erect barriers like fences or burlap to protect from wind
• Periodically spray plant foliage with an antidesiccant to prevent winter burn
• Keep soil evenly moist, checking moisture levels often. Watering less often encourages deeper roots
• Fertilize sparingly with lower nitrogen mixes designed for winter growth
• Remove any remaining fruit left on plants to reduce disease risk
• Monitor for pests that thrive in cold weather, like mites
• Once warmer weather returns, prune back growth and transition plants slowly into new fruit production

Even with the best care, tomato plants often struggle to thrive through a harsh winter outdoors. But in warmer regions, focused efforts can sometimes keep them alive and productive for an extra season.

Best Tomato Varieties For Colder Climates

While all tomatoes prefer warm weather some types perform better than others when temperatures drop:

• Siberian tomato – This Russian heirloom was bred to set fruit in cooler conditions down to 45°F making it one of the best for maximizing harvests in short seasons. The 1-2 ounce red fruit grow well both in containers and the ground.
• Sub Arctic Maxi – An early maturing variety that can set and ripen fruit well in zones 2-5. Large meaty fruit grow to 6-8 ounces on fairly compact vines.
• Oregon Spring – One of the earliest varieties at only 53 days from transplant to ripe fruit. Small round fruit sets prolifically even at lower temperatures.
• Bloody Butcher – These small red tomatoes produce decent sized crops and ripen early in cool conditions. An heirloom variety that has been grown since the mid-1800s.
• Polar Star – A compact determinate tomato bred by the University of Alaska Fairbanks for high latitude, short season areas. Sets golfball sized round red fruit.
• Glacier – Another cold tolerant variety developed at the university with a similar compact, determinate habit. Fruit are a bit larger at 2-3 inches across.
• Mountain Princess – Sets reliably in cooler conditions and relatively short days in zone 5 and below. Medium-large elongated fruit with good flavor.
• Legend – A very early maturing Roma-type plum tomato ideal for short season climates in zones 3-6. Great for cooking and processing due to the meaty flesh and few seeds.

With the right variety selection and protection techniques there are often more opportunities to grow tomatoes in cold climates than people realize. Don’t let a little frost slow down your tomato ambitions!

Winter Protection Methods For Tomato Plants

As temperatures drop heading into winter, frost and freezing conditions can quickly damage or kill back tomato plants. However, there are ways to help protect plants and allow them to keep producing longer into the fall and early winter months. Here are some key methods for providing winter care and frost protection for tomato plants:

Row Covers

Row covers create a protective layer of insulation over plants while still allowing air and water exchange. They help trap radiant heat close to the plants, allowing tomatoes to remain viable 5-10 degrees below the actual air temperature. Common materials used are polyester, spunbond polypropylene, and polyetyhylene fabrics. Look for a 0.55 to 1.25 oz/yd durability. Sturdier 1.5-2 oz fabrics provide more frost and wind protection. Make sure to allow for ventilation during the day to avoid overheating.

Key Points:

• Provides 4-8°F frost protection typically
• Allows air and moisture exchange while trapping heat
• Can be draped directly over plants or suspended on hoops
• Ventilate during day to avoid excess heat buildup
• Agribon and Reemay are common brands

Cold Frames

Cold frames are enclosed outdoor structures built low to the ground to trap solar radiation and protect plants. Older designs use glass windows but modern ones favor polycarbonate plastic for durability and light transmission. The roof is angled towards the south to maximize sunlight. Vents along the side and top allow for manual temperature control. Cold frames allow tomatoes to be grown late into fall or started very early in spring extending the season.

Key Points:

• Provides insulation and wind protection
• Solar radiation warms interior air during the day
• Manual venting prevents overheating on sunny days
• Can provide up to 20°F frost protection when closed at night
• Permanent structures typically 2-3 ft tall built over garden beds

Wall O’ Waters

These simple devices consist of clear plastic water filled tubes formed into a cylinder around plants. The water absorbs heat during the day and releases it at night creating a warmer microclimate inside the barrier. For mature plants use Wall O’ Waters with 17mm diameter tubes. Make sure to refill with warm water as needed if freezing occurs.

Key Points:

• Provides up to 25°F frost protection
• Water absorbs and radiates heat creating greenhouse effect
• Available in sizes for both seedlings and larger plants
• Refill with warm water if freezing causes tubes to empty
• Reusable for many seasons

Hot Caps And Cloches

A hot cap is a small waxed paper or plastic cone that is placed over individual plants to trap warm air close to the plant. Cloches are a similar concept but made out of glass or plastic materials formed into a tent like shape. These covers all provide a few degrees of frost protection by preventing cold air from reaching plants. Make sure to provide ventilation to avoid overheating during the day.

Key Points:

• Protects individual plants with reusable covers
• Traps pockets of warm air around foliage
• Provides 2-5°F frost protection
• Must be vented during day to prevent excess heat
• Can be placed directly over plants or on supports

Raised Beds With Heating Cables

For season extension into seriously cold winter weather some growers use hydronic heating cables buried under their raised garden beds. Cables are laid at correct spacing and depth then covered with soil. A thermostat regulates the heat output keeping the entire soil root zone frost free. While plants above ground remain unheated this allows roots to continue functioning and plants to keep growing.

Key Points:

• Keeps plant root zones from freezing with underground heating cables
• Allow production to continue despite cold air temperatures
• Automated thermostats control heating levels
• Can allow tomatoes to be grown year round even in cold climates
• More complex systems best for commercial protected agriculture

Tips For Success

• Check weather forecasts daily and be ready to deploy protection ahead of cold nights
• Ventilate structures during the day to avoid overheating
• Insulate raised bed or container root zones with mulch
• Wrap or cover trunks of tender perennials
• Use thermometers inside protective structures to monitor conditions
• Remove covers or open vents as soon as possible after temperatures rise
• Be ready to harvest green fruit ahead of hard freezes

Tomato Winter Growing Conditions

While tomatoes thrive during warm summers, their growing season can potentially be extended well into winter in some milder climates. Here are the winter conditions tomatoes need to survive and remain productive:

Light Levels

Tomatoes require at least 8-10 hours per day of direct sunlight for adequate growth and fruit production. In winter this can be a challenge in some regions due to shorter days, cloudy weather, and low angle sunlight. Supplemental lighting may be needed to maintain fruiting through short winter days. High intensity discharge (HID) or LED grow lights can be used to maintain ideal light levels.

Temperature Ranges

Tomato growth completely stops below 50°F and plants suffer damage once air temperatures reach freezing. Ideal daytime temperatures for growth and fruiting are 65-85°F. Nighttime temps between 55-65°F are recommended. With protection from wind and proper insulation tunnels and row covers can help maintain viable microclimates around plants. Sub-surface heating cables can also keep root zones warm.

Humidity Levels

Average relative humidity of 60-70% is best for tomato growth. Levels much above 80% favor disease development in most cases. Greenhouses and tunnels often need ventilation and air circulation to avoid excessively high humidity in winter. However, extremely dry winter air can also damage and desiccate plants. Misting systems and humidifiers may help in arid winter climates.

Watering Requirements

Tomato water needs drop significantly in winter but the soil should never be allowed to fully dry out. Test moisture levels regularly 2-3 inches below the surface. Water when the top few inches become slightly dry. Reduce frequency but provide deep soakings to encourage stronger root growth. Mulch and row covers help conserve soil moisture. Drip irrigation is ideal to target watering needs.

Winter Fertilizer Application

While nitrogen demands drop in winter, tomatoes still require adequate phosphorus and potassium for fruit production. Use lower nitrogen fertilizers or apply at 1/2 normal strength. Fish emulsion, compost tea, worm castings, and seaweed extracts are good organic options. Monitor plants for signs of deficiencies and adjust fertility regimes as needed.

Pest And Disease Pressure

Cool moist conditions can increase disease problems in winter tomatoes including blights, mold, mildew, and fungal issues. Preventative spraying with copper, sulfur, or horticultural oils is recommended. Monitor for pests like aphids, whiteflies, and mites which thrive in cooler temps. Have a pest management strategy in place before issues arise.

Tomato Winter Pruning And Trellising

Pruning and trellising techniques need to be adjusted for overwintering tomato plants. The goals shift from maximizing fruit production to just keeping the plants alive. Here are some tips:

Reduce Pruning

Pruning should be minimized to avoid removing foliage the plant needs to sustain itself through tough conditions. However, select pruning can help direct energy and remove non-essential growth:

• Prune out all dead or dying leaves and stems which can harbor disease
• Remove branches with no fruit set to de-energize them
• Pinch or cut back leggy growth to encourage branching
• Prune to open up the center of dense plants for light and air penetration
• Cleanly remove damaged or broken branches back to a healthy junction

Lower Or Remove Trellises

In areas with heavy winter snow tall trellises can actually damage plants if allowed to collapse under the weight. Consider lowering or removing temporary trellis supports. However short and strong trellis systems are still beneficial:

• Keeps plants supported and protects from breaking
• Allows light distribution through open structure
• Provides easy attachment points for protective covers
• Can be weighed down or reinforced if snow load is a concern

Staking And Low Support Methods

Individual staking or cages give great results for overwintered tomatoes:

• Use strong 8 ft stakes pounded 1-2 ft into the ground
• Attach plants loosely with soft twine or plant tape
• Opt for short, heavy duty wire cages over taller versions
• Low fencing like sheep wire provides flexible support
• Weave plants through holes in concrete reinforcing wire laid on raised beds

The goal is not to force upright growth but rather provide support and prevent major stem damage through the winter.

Greenhouse Winter Tomato Care

Growing tomatoes through the winter is possible with a high quality greenhouse. Here are some key tips for off-season tomato care:

Temperature Regulation

Maintain daytime temperatures between 65-85°F and nighttime lows above 55°F. A programmable thermostat controlled heater is ideal. Locate heaters properly to distribute warmth efficiently. Insulate foundations, walls, and ceilings to retain heat. Thermal mass like water barrels help stabilize temps.

Ventilation And Air Circulation

Ventilation prevents overheating on sunny winter days which can damage plants. Roof vents, side windows, and fans are essential. Avoid humidity build up by exchanging stagnant interior air for fresher exterior air when possible. Good airflow suppresses disease.

Supplemental Lighting

High intensity discharge (HID) or LED fixtures may be needed to maintain ideal light levels for growth and fruiting. Use a combination of overhead and inter-lighting. Ensure lights provide ample red (600-700 nm) and blue (400-500 nm) wavelengths. Run supplemental lights to extend daylength to 16 hours when required.

Water And Fertility Management

Test moisture levels frequently and irrigate conservatively during winter. Fertilize based on plant health and testing. Lower nitrogen levels to avoid excessive leafy growth. Focus on adequate phosphorus and potassium for fruit production. Monitor for nutritional deficiencies and make corrections promptly.

Pruning And Trellising

Less pruning is required in winter. Remove dead/diseased branches and just enough foliage to open up the center of plants. Trellises should be strong enough for heavy winter fruit and adaptable for covering and venting as needed.

Pest And Disease Prevention

The enclosed greenhouse environment favors certain pest and disease issues. Maintain strict sanitation removing leaf litter and fallen fruit which harbor problems. Monitor for aphids, whiteflies, spider mites and other pests. Apply organic sprays like neem oil or insecticidal soap preventatively. Improve airflow and promptly treat any fungal issues.

Energy Conservation

Reduce heat loss and energy waste by sealing leaks, insulating well, and closing curtains at night. Only ventilate when necessary to regulate temperatures. Lower thermostat temperatures at night and anytime greenhouse will be vacant. Limit traffic in and out of the greenhouse in the depths of winter.

Backup Systems

Install backup generators to maintain critical systems during outages. Have spare parts available for repairs. Invest in a secondary heating source like a wood stove to supplement main heating in emergencies. Plan for extreme cold, storms, or other issues that could impact the greenhouse environment.

With the right greenhouse setup and diligent management tomatoes can fruit successfully even in cold winter conditions. Consistent monitoring and adjustment is key to maintaining ideal growing conditions year round. The results of vine-ripe winter tomatoes are worth the extra effort for many growers.

Tomato Varieties For Winter Greenhouses

When selecting tomato varieties for winter greenhouse cultivation, prioritize plants with these traits:

Compact Determinate Types

More compact determinate tomatoes that cease growth after reaching a certain size are preferable. They conserve energy rather than put it all towards unchecked growth making them easier to maintain through short winter days. Good options include ‘Red Robin’ and ‘Bush Champion II’.

Early Maturing

Quickly maturing varieties from transplanting to ripe fruit allow for a worthwhile harvest even in winters shorter growing season. Look for maturity dates under 60 days. ‘Siberia’ and ‘New Big Dwarf’ are two good choices.

Parthenocarpic Fruit Set

Parthenocarpic varieties are able to set and ripen fruit naturally in lower light and cooler temperatures common in winter greenhouses. Try selections like ‘Dr. Carolyn’ and ‘Mountain Princess’ which possess this trait.

Disease Resistance

Disease pressure is higher during winter greenhouse growing. Start with varieties exhibiting V, F, N resistance to key pathogens like verticillium wilt, fusarium wilt, root knot nematodes. This gives plants a fighting chance against problematic diseases.

Determinate Cherries

Cherry tomatoes stop growing once fruit sets thanks to their determinate habit. Their smaller fruit size also ripens quicker with less heat units required. Try winter hardy varieties like ‘Snowberry’ and ‘Terenzo’.

Productive In Low Light

Look for varieties described as productive in low light scenarios. ‘Endurance’ and ‘Komeett’ are two types that will help maximize yields if supplemental lighting is insufficient.

A successful winter tomato crop starts with selecting cold tolerant rapid maturing varieties matched to the specific growing conditions and challenges winter will pose in your greenhouse environment.

Tips For Container Winter Tomatoes

Growing tomatoes in containers allows them to be moved into protective structures as needed when temperatures drop. Here are tips for successfully cultivating tomatoes through winter in pots:

Pot Size And Location

Use at least 15-25 gallon containers for full size plants, 10 gallons for determinate types, and 5 gallons for cherry or patio varieties. Provide as much direct sun as possible utilizing a bright south facing location. Keep pots mobile to move into sunlight or cover as needed.

Insulated Root Zone

The container root zone must be protected from freezing. Wrap outside of containers with insulation like bubble wrap or foam sheets. Place smaller pots inside a larger insulated box. Line interior bottom with rigid foam board. Mulch heavily over soil surface.

Wind Protection

Use barriers like fences, fabric, burlap, or straw bales to block cold winds which quickly desiccate and damage exposed container plants. Build temporary cold frames around pots to protect from wind and retain heat.

Row Covers And Cloches

Place fabric row covers or plastic cloches over the top of containers to provide several degrees of frost protection. Ventilate cloches during day to prevent overheating inside. In heavy freezes, wrap entire pot with row cover securing the bottom.

Thermal Mass

Add jugs or containers of water within the pot to act as thermal mass. Water absorbs heat during daytime and releases it slowly at night warming roots and soil. Replace with warm water if jugs begin to freeze. Phase change materials also stabilize temperatures.

Off-season Fertilizer

Continue fertilizing container tomatoes year round but reduce nitrogen levels in winter. Look for formulas with more P and K for fruit development and lower N for reduced vegetation. Fish emulsion, seaweed extract, and compost or worm castings make good organic options.

With the right varietal selections and proper overwintering protections, it is possible to keep container tomatoes actively growing and fruiting even through cold winter months.

Tomato Frost Protection Techniques

When frost threatens, home gardeners have several options to protect vulnerable tomato plants. The key is taking action before freezing conditions arrive:

Harvest Green Fruit

Pick any mature green or ripening fruit still lingering on plants. You can ripen these indoors on a sunny windowsill or countertop over several weeks. Discard diseased or damaged fruit which won’t store well.

Move Container Grown Plants

If growing tomatoes in pots, move them into a protected greenhouse, coldframe, or covered porch area safe from frost. Keep plants away from exterior walls which radiate cold. A portable heater can allow continued harvest.

Deploy Protective Covers

Various coverings can shield plants and trap heat. Fabric row covers, hot caps, cloches, and Wall O’ Waters insulate down to 25-30°F if deployed properly ahead of freezing weather. Make sure to provide ventilation on sunny days.

Water Well Before Frost

Avoid stress. Water plants 1-2 days before a frost to ensure the soil is adequately moist. Wet soil holds more heat than dry. But avoid excess moisture which can exacerbate cold damage.

Avoid High Nitrogen Fertilizers

Nitrogen promotes tender growth vulnerable to cold damage. Taper off higher nitrogen fertilizers in fall. Instead focus on phosphorus and potassium applications if fertilizing overwintered plants.

Provide Insulating Mulch

Apply up to 12 inches of loose straw, leaves, pine needles, or other organic mulch around the base of the plants. This helps insulate the soil and protect roots from extreme fluctuations in temperature.

Minimize Pruning And Defoliation

Leave all leaves on the plant to maximize natural insulating effects. Avoid pruning unless diseased, dead or crossing branches must be removed so the plant retains its cold hardiness.

Erect Wind Barriers

Use fences, fabric, burlap, or other screens to protect plants from direct exposure to cold winds which accelerate chilling damage. Stake and tie up any tall or spindly growth.

By proactively preparing tomato plants using protective measures, gardeners can often keep them alive and productive well into the fall season beyond the first lighter frosts. Just be ready to take action as soon as cold conditions are forecast.

Tomato Frost Damage Symptoms

Frosts often catch tomato growers off guard. But learning to identify cold damage quickly allows saving affected plants. Here are the most common tomato frost damage symptoms:

Wilted or Drooping Leaves

Tissues rapidly dehydrate and wilt when frozen. Mild or patchy frosts cause random wilting of individual leaves first which then spreads if cold intensifies. Check for wilted tops or branches drooping downward from the weight of damaged foliage.

Discolored Stems

Stems exhibit chilling injury before leaves. Look for water-soaked translucent patches on stems turning necrotic brown or black. Peel back bark to examine if damage penetrated deeper into the vascular tissues.

Tan or Bleached Leaf Spotting

Small tan flecks appear on leaves after exposure to light frost. Entire leaf surface may develop a bleached off-white appearance in harsher freezes. Often the upper canopy shows damage before lower leaves.

Splitting of Stems and Branches

As water inside tissues freezes it expands rupturing cell walls. This causes splitting of stems and branches, especially along segments where two meet. Cracks exude watery sap and pith will appear separated.

Accelerated Leaf Drop

Frozen leaves rapidly dehydrate, die off and fall from the plant soon after exposure to frost. Some natural leaf loss occurs in fall but is accelerated significantly post freeze events.monitor for rapid defoliation.

Dark Water-soaked Roots

Dig carefully around the base of affected plants to inspect roots. Dark, mushy, foul smelling roots indicate freeze damage to the root system. Healthy white feeder roots will be absent.

Catching symptoms quickly allows salvaging plants using protective measures before irreversible damage occurs. Be ready to deploy emergency protections at the first sight of chilling injury.

Protecting Tomato Plants From Early Frost

Despite best efforts, an early unexpected frost can threaten prized tomato plants. When forecasts call for cold below 40°F, here are last-minute things that help protect tomatoes:

Water Plants Thoroughly

Moist soil holds heat much better than dry during frosts. Water plants deeply 1-2 days prior so the entire root zone is hydrated. Drip irrigation works well to soak soils without wetting foliage.

Harvest All Mature Fruit

Pick any ripened or ripening fruit still clinging to vines. You can finish ripening indoors. Work quickly but carefully to avoid damaging plants. Discard any diseased or split fruit.

Move Container Plants

Relocate containers holding tomatoes into a greenhouse or enclosed porch safe from frost. Avoid exterior walls that radiate cold. Small plants can be placed together for mutual warmth and protection.

Drape Sheets or Burlap

Simple lightweight fabrics help trap pockets of warm air around plants. Old sheets, row cover fabric, burlap, or landscape fabric can be spread directly over plants and secured at the base with stones, bricks, or soil.

Invert Large Containers

For individual plants, place large buckets or nursery pots overturned on top of plants with the rim sealed to the ground using soil. Remove or ventilate them daily to avoid overheating plants.

Apply Organic Mulch Heavily

Spread up to 12 inches of loose straw, leaves, pine needles or other organic materials around the base of plants. This insulates the soil helping protect root systems from extreme temperature swings.

Set Up Temporary Walls

Use any material on hand like old doors, plywood, bales of straw, etc. to erect temporary barriers that block exposure to winds which accelerate chilling. Just a day or two of protection can make a big difference.

Staying vigilant and being creative with available supplies allows resourceful gardeners to take proactive steps protecting tomatoes, even when frost catches you off guard at the end of the season. Don’t give up too early!

Tomato Cold Tolerance By Type

Not all tomatoes have the same level of sensitivity to cold conditions. Here are some generalized guidelines for cold hardiness among different tomato types:

Cherry Tomatoes

Most tolerant of cold and light frosts. Often fruit within a couple weeks of transplanting. Lose leaves and stop flowering once night temps drop into 30s. Popular hardy cherry types: Sungold, Sweet 100s, Juliet.

Grape Tomatoes

Moderately hardy, especially compact varieties like Santa F1. More prone to splitting in extreme cold than standard cherries. Will slow growth significantly once night temperatures drop below 40°F.

Small Fruited Types

Very early varieties like Glacier and Oregon Spring mature fruit quickly and resist light frosts. But prolonged exposure below 45°F will hamper most small tomato yields besides protected cherries.

Slicers And Beefsteaks

Generally the least cold tolerant tomatoes. Larger fruit takes longer to mature which increases exposure to cold damage. Growth declines rapidly below 50°F for most full-size slicing types. Require most protection in fall.

Romas And Plum Types

Moderately tolerant of chill. Compact growth habit helps limit exposure. Fleshy fruits not as prone to splitting. Among the best for extending harvests into cooler fall weather if protected.

Patio And Container Varieties

Specifically bred more compact varieties withstand colder temps better than sprawling indeterminate types. But any tomato plants in containers require extra frost protection measures for roots.

Knowing which tomato types have the best natural cold resistance helps guide fall plantings and overwintering decisions based on seasonal temperatures in your specific growing region and conditions.

Tomato Cold Protection DIY Methods

In addition to standard covers and cloches, there are many creative Do-It-Yourself techniques gardeners have come up with over the years to protect tomato plants in cold weather:

sheets and Blankets

Old blankets and sheets can be draped or framed over plants and anchored with rocks or bricks to provide an insulating barrier from frost. Avoid any with moisture resistant coatings. Use clips to fasten together multiple layers for more warmth.

Foam Pipe Insulation

Slit small diameter piping lengthwise and secure around stems and branches. The foam helps insulate tender tissues from temperature extremes. Useful for added protection beneath other covers.

Newspaper or Cardboard Cones

Make newspaper or cardboard cones around individual plants. Cover the cone with clear plastic anchored around the bottom edge. The air gap provides insulation against cold while allowing light through the plastic.

Plastic Jugs or Bottles

Cut the bottom off empty plastic containers. Place over transplants or short staked plants nesting them into the soil. Screw on original bottle tops to help hold in warmth yet allow ventilation.

Storage Boxes With Plastic Liners

Invert large clear plastic storage bins over plants and line the interior with plastic sheeting or tarps to create a greenhouse effect. Weigh down edges with soil or pavers to seal.

Water Walls

Use clear 2-liter bottles, milk jugs, or large containers arranged in a circle around plants and filled with warm water. The thermal mass absorbs heat during the day releasing it at night.

Container Mini-greenhouses

Build customized enclosures from wood, PVC, old windows, etc. sized to fit over container plants. Use poly sheeting covers, secure closable vents, and insert small heat sources if desired.

Don’t be afraid to think outside the box and make use of household items for emergency frost protection. Speed and preparation are key to saving plants using these last resort techniques.

Identifying And Preventing Tomato Chilling Injury

Exposure to even cool temperatures above freezing can damage tomato fruits and foliage. Here is how to identify and prevent chilling injury in tomatoes:

Symptoms

• Surface pitting, sunken lesions, or large discolored blotches on ripening fruit
• Failure of fruit to properly ripen – remaining orange/yellow
• Bronzing, browning or whitening of leaves
• Wilting of shoots and leaves
• Water-soaked lesions on stems turning necrotic

Causes

• Night time temperatures consistently below 55°F
• Daytime highs failing to reach above 75°F
• Wide fluctuations in day/night temperatures
• Excess soil moisture coupled with cool conditions

Prevention Tips

• Use protected growing structures like low tunnels to regulate temps
• Position containers against warm walls or group together
• Insulate containers with bubble wrap or foam boards
• Allow thorough foliage drying each morning by improving airflow
• Heat root zones with heating cables or buried hot caps
• Switch to chilling resistant tomato varieties
• Maintain optimal soil fertility and avoid over-watering
• Paint containers white to reflect more heat onto plants

Catching tomatoes early and improving conditions can reduce further chilling damage. But preventing exposure to prolonged cool temps is key to avoid this issue.

Extending Tomato Harvest Past Frost

Do not lose hope for continued fresh tomatoes just because the first fall frost has struck. There are still ways to harvest longer into the season:

Protect and Insulate Plants

Depending on frost severity, plants can be covered and shielded allowing further ripening on the vine before harder freezes kill off growth completely. Be ready to deploy emergency plant protections.

Pick Any Ripening Fruit

Harvest all full sized green or mature fruit still clinging to the vines. Ripening can be completed on sunny windowsills over 2-4 weeks. Flavor is not quite as good as vine ripened but still enjoyable.

Pick Green Tomatoes For Cooking

Collect any remaining green tomatoes to be used in fried green tomatoes, chutneys, relishes, and salsas. These all utilize green fruit before it has a chance to ripen. Recipes abound online.

Dry and Freeze for Sauces

Pull whole plants up by the roots or remove stems with fruit clusters. Hang in a dry sheltered location to desiccate fruit, then freeze for winter sauce making. Small cherry and grape tomatoes dry best whole.

Invest In Season Extending Devices

Consider erecting small portable greenhouses, high tunnels, cold frames, or other protective growing structures which allow much longer harvests past fall frosts when managed properly.

Start Plants Earlier Next Year

Get seedlings going indoors 4-6 weeks ahead of your average final spring frost date. Transplant them out immediately once ground is workable to maximize days of production before cold fall weather returns.

With proper cold protection measures, determination, and good organization, backyard tomato gardeners can often enjoy weeks more fresh harvests from their prized plants beyond the first few teasing frosts.

Tomato Cold Hardening Techniques

To improve tomato cold tolerance for winter or early spring plantings,ardeners can employ these methods to “harden off” transplants:

Gradually Expose To Cool Temps

Around 2-3 weeks before planting, move seedlings outdoors to sheltered spots for short periods. Slowly increase the duration and decrease temperature over 10-14 days to transition plants to colder conditions. Avoid exposure if frost threatens.

Reduce Water Slightly

Plants overly saturated with water are more prone to chilling damage. As hardening off begins, let plants dry out more between irrigations. This encourages deeper root growth.

Use Low Nitrogen Fertilizer

High nitrogen levels result in tender growth. Switch to low nitrogen or phosphorus-potassium focused fertilizers. Mature compost tea also works well. Stop fertilizing altogether a week before transplanting.

Allow Moderate Water Stress

Somewhat counterintuitively, moderate water stress helps produce sturdier growth that resists cold shock. Don’t severely under-water, but avoid continually saturated soil.

Expose To Wind

Gently blowing air on seedlings toughens cell walls. Set up a small fan to run intermittently on low speeds. Ensure plants are staked well to avoid breakage.

Alter Day/Night Temps

Fluctuate greenhouse or indoor growing area temperatures to mimic outdoor diurnal swings. Dropping temps into the 50s F at night and allowing days in the 70s F helps adjust plants.

Sever Transplant Roots

Gently disturbing the root ball when transplanting triggers helpful stress responses. Carefully sever thicker side roots and tousle the bottom third of the root ball.

Transplant On A Cloudy Day

Cool overcast days are easier for newly hardened off transplants. Direct sun and heat too soon after transplanting causes additional shock.

Follow these tips and tomato transplants will be primed to perform in cool conditions just after planting out. Hardening is especially useful for very early or very late season plantings.

Tomato Frost Protection For Container Plants

Container tomatoes need special considerations to protect their exposed roots from cold damage beyond what garden plants experience:

Relocate Containers

Move pots against warm, protected walls or into greenhouses, garages, etc before frost threatens. Avoid areas that radiate cold including near AC units. Cluster containers together to conserve warmth.

Insulate Pots

Wrap outside of containers with bubble wrap, foam sheets, burlap, etc. Elevate off cold surfaces. Place smaller pots into a larger insulated box. Line the bottom with rigid insulation.

Provide Row Covers

Secure fabric row covers over the tops of containers to protect plants. For flexible plastic containers, wrap the entire pot with covers sealing the bottom edges.

Utilize Thermal Mass

Place jugs or buckets of warm water within pots. The water absorbs and radiates heat to warm soils and roots. Replace with fresh warm water if containers freeze solid.

Add Heat Sources

Small portable heaters or outdoor rated heating cables can be used to maintain temperatures inside protected enclosures containing potted tomatoes.

Shelter From Wind

Use windbreaks around pots to protect from desiccating winds which accelerate heat loss. Burlap, straw bales, fences, fabric, etc can shield plants.

Check Soil Moisture

Ensure containers are watered adequately before a freeze but avoid saturated conditions which makes roots more prone to freezing. Check moisture levels 2-3 inches down.

With some preparation and vigilance, container tomatoes can often continue thriving well past the average first fall frost dates. Don’t give up too quickly at the first signs of cold weather.

Tomato Frost Protection For Raised Beds

In-ground tomatoes in raised bed gardens have their own specific frost protection needs:

Utilize Row Covers

Floating row covers directly over beds are easy to deploy and provide several degrees of frost protection. Use hoops to drape covers if not directly resting atop plants.

Mulch Heavily Around Plants

Apply up to 12 inches of loose organic mulch atop beds to insulate soil. Leaves, straw, pine needles, wood chips all work. It protects roots from freezing. Replenish settled mulch.

Add Cold Frames

Build customized cold frames sized to your raised beds. Use hinged, transparent covers that lift for ventilation. A thermometer inside helps monitor conditions.

Protect Trunk and Stems

Wrap lower trunks of plants or interior stems with commercial insulation products, pipe wrap, burlap, etc. Avoid pruning lower leaves so plants retain natural insulation.

Erect Wind Barriers

Use fencing, burlap, fabric, straw bales or other materials as needed to block beds from prevailing winds. Stake tall or exposed plants to keep foliage from whipping in wind.

Manage Soil Moisture

Cold damage is worse in saturated soils. Test moisture levels around plants and water beds 1-2 days before expected frost to ensure adequate hydration without excess saturation.

Avoid High Nitrogen Fertilizers

Reduce late season nitrogen which causes tender growth. Focus on phosphorus and potassium applications before winter for hardier plants.

With some simple preparations, raised bed tomatoes can continue thriving and producing weeks longer into the fall season than exposed plants. Prioritize proactive protection methods.

Tomato Winter Greenhouse Varieties

When selecting tomato varieties for winter greenhouse cultivation, prioritize plants with these traits:

Compact Determinate Types

More compact determinate tomatoes that cease growth after reaching a certain size are preferable. They conserve energy rather than put it all towards unchecked growth making them easier to maintain through short winter days. Good options include ‘Red Robin’ and ‘Bush Champion II’.

Early Maturing

Quickly maturing varieties from transplanting to ripe fruit allow for a worthwhile harvest even in winters shorter growing season. Look for maturity dates under 60 days. ‘Siberia’ and ‘New Big Dwarf’ are two good choices.

Parthenocarpic Fruit Set

Parthenocarpic varieties are able to set and ripen fruit naturally in lower light and cooler temperatures common in winter greenhouses. Try selections like ‘Dr. Carolyn’ and ‘Mountain Princess’ which possess this trait.

Disease Resistance

Disease pressure is higher during winter greenhouse growing. Start with varieties exhibiting V, F, N resistance to key pathogens like verticillium wilt, fusarium wilt, root knot nematodes. This gives plants a fighting chance against problematic diseases.

Determinate Cherries

Cherry tomatoes stop growing once fruit sets thanks to their determinate habit. Their smaller fruit size also ripens quicker with less heat units required. Try winter hardy varieties like ‘Snowberry’ and ‘Terenzo’.

Productive In Low Light

Look for varieties described as productive in low light scenarios. ‘Endurance’ and ‘Komeett’ are two types that will help maximize yields if supplemental lighting is insufficient.

A successful winter tomato crop starts with selecting cold tolerant rapid maturing varieties matched to the specific growing conditions and challenges winter will pose in your greenhouse environment.

Tomato Winter Care Priorities

Here are the key areas tomato growers need to address to keep plants thriving through winter:

Temperature Management

Prevent frost damage and maintain ideal growth temps. Use row covers, cloches, and other protective devices. Move containers to warmer areas. Insulate raised beds and root zones.

Adequate Lighting

Supplement natural light if drops below 10 hours per day. Use grow lights or locate plants in the brightest windows. Maximize sunlight capture in greenhouses.

Air Circulation

Prevent mold, mildew and disease development. Improve ventilation and air exchange. Prune selectively to open up centers of dense growth. Employ fans if helpful.

Soil Moisture Management

Avoid drought or overwatering. Check soil moisture levels frequently. Water thoroughly when top few inches become dry. Use drip irrigation. Mulch helps conserve moisture.

Nutrition Monitoring

Watch for signs of deficiencies indicating lower fertility needs. Reduce nitrogen levels but continue providing other key nutrients. Use lower strength liquid feeds or compost tea.

Pest And Disease Prevention

Scout regularly and act quickly if pests like whiteflies or mites appear. Apply preventative sprays for common disease pathogens. Remove fallen leaves and fruits to eliminate hiding places.

Diligent winter care revolves around monitoring plants closely and taking prompt action to address any issues in their protected cultivation environment.

Tomato Winter Greenhouse Temperature Maintenance

Regulating temperatures is vital for successfully growing tomatoes through the winter months in greenhouses:

Heating Systems

Reliable, programmable heating systems are essential. Natural gas and propane heaters coupled with thermostats work well. Maintain ideal temps between 65-85°F during day and >55°F at night.

Insulation

Retain heat and reduce losses by insulating foundation, walls, roof, and curtains. Use double poly films on walls and roof. Seal any gaps or leaks. Add energy curtain insulation.

Thermal Mass

Add materials like water barrels, concrete blocks, stone, etc. that absorb and radiate heat in the greenhouse. Position near plants to help stabilize temperatures.

Ventilation And Air Exchange

Vents, windows, shutters, and fans help regulate temperatures on sunny winter days. Improved airflow also reduces humidity and disease pressure.

Monitoring And Management

Actively measure conditions using max/min thermometers. Increase ventilation on warmer sunny days. Add a backup heat source. Have a plan if main heater fails.

Emergency Preparedness

Install backup generators for electrical outages that could disable heating and lighting. Maintain adequate fuel supplies. Have spare parts for repairs and qualified technicians on call.

Vigilant temperature control and contingency planning allows year-round tomato production even through harsh winters in a well managed greenhouse environment.

Tomate Plant Winter Care And Maintenance Tips

Here are some tips for caring for tomato plants over the winter:

• Move potted plants to a protected area such as a greenhouse or sunny window. Ensure temperatures remain above 55°F.
• Prune plants by removing dead leaves and branches to discourage disease. Avoid heavy pruning to retain leaves.
• Check soil moisture frequently, watering when the top few inches become dry. Avoid soggy soil which can cause root rot in cold conditions.
• Consider using a grow light to supplement natural sunlight if it falls below 8-10 hours per day. LED grow lights work well indoors.
• Fertilize moderately with a lower nitrogen formula to avoid leggy growth. Fish emulsion or compost tea make good organic options.
• Monitor for pests like aphids and whiteflies which can thrive in greenhouses. Take action early to control any infestations.
• Improve air circulation with small fans to prevent fungal or bacterial diseases in stagnant indoor conditions.
• Inspect roots and repot into fresh pasteurized potting mix if they become pot bound or show signs of root rot.
• Insulate pots by wrapping the outside with bubble wrap or foam sheets. Place smaller pots inside larger insulated boxes.
• Provide supports like cages and stakes to prevent branches from breaking under the weight of winter fruit.
• Pick ripe fruit often to encourage continued production. Flavor may decline but winter harvests are still worthwhile.

With a little specialized care, potted tomato plants can continue to thrive and produce through the winter months indoors.

Tomato Winter Harvest Tips And Tricks

Here are some useful tips for maximizing tomato harvests during the winter season:

• Select quick-maturing varieties under 60 days to ripe fruit. Good options include ‘Siberia’ and ‘New Big Dwarf’.
• Prioritize disease-resistant cultivars that can better handle cooler, more humid conditions. Look for V, F, N resistance traits.
• Prune minimally to maintain as much foliage as possible for fruit protection and energy production.
• Stake and trellis plants for support but avoid overly tall structures that could collapse from heavy snow loads.
• Heat greenhouse floors or raised beds with heating cables to keep roots warmer than the air.
• Boost CO2 levels to around 800-1200 ppm to optimize fruit production. Propane generators work well as CO2 sources.
• Hand pollinate flowers using a soft brush to ensure adequate pollination during winter when bee activity declines.
• Pick fruits slightly early before deep cold snaps and finish ripening indoors. Flavor won’t be quite as good as vine-ripened.
• Blood meal and calcium supplements can help reduce issues like blossom end rot in low light conditions.
• Maintain strict sanitation to limit disease issues. Remove all fallen leaves and debris in the greenhouse promptly.
• Be prepared to provide supplemental lighting if sunlight drops below 10 hours per day. LED grow lights work well indoors.

Take advantage of these tips and greenhouse tomatoes can produce reliably even in the darkest days of winter!

Conclusion

Although tomatoes prefer warm weather, their growing season can be extended well into winter with proper protections and care. Committed gardeners have many options to safeguard plants against frost and freezing temperatures. Row covers, greenhouses, cold frames, and growing in containers all allow tomatoes to thrive longer even in colder climates. Selecting less cold-sensitive varieties, hardening off transplants, and maintaining optimal nutrients and moisture also improves resilience. While production slows during winter, protected tomatoes will continue flowering and setting ripe juicy fruit for harvest through the coldest months. Don’t let the first fall frost spell the end of fresh tomatoes – with a little preparation they can produce long past the traditional warm season end date in many areas. The rewards of vine-ripe winter tomatoes are well worth the extra effort required.