When To Plant Tomatoes In Wisconsin? (Best Time)

When To Plant Tomatoes In Wisconsin?

Welcome to our comprehensive guide on planting tomatoes in Wisconsin. This section will discuss the optimal time for planting tomatoes in Wisconsin and provide a comprehensive guide tailored explicitly to Wisconsin’s climate and conditions.

Knowing when to plant tomatoes is crucial for a successful harvest. The best time to plant tomatoes outdoors in Wisconsin is after the last frost date, typically around mid-May. However, the exact date may vary depending on your location in Wisconsin.

Understanding Wisconsin’s Climate for Tomato Planting

When To Plant Tomatoes In Wisconsin

Before we dive into the specifics of tomato planting, it’s essential to understand Wisconsin’s climate and how it affects tomato growth. Knowing this information will allow you to make informed decisions about your planting schedule and help you maximize your tomato yield.

Climate Factor Details
Average Temperatures Wisconsin experiences a wide range of temperatures, with average lows ranging from 15°F (-9°C) to 60°F (15°C) and average highs ranging from 20°F (-6°C) to 80°F (27°C). This temperature variation can impact the growth of tomato plants, making it essential to choose appropriate planting times and varieties.
Frost Dates Wisconsin’s frost dates vary depending on the region. Still, generally, the last frost date occurs between mid-May to early June, and the first frost date occurs between late September and early October. These frost dates need to be considered when deciding when to plant tomatoes.
Soil Wisconsin has clay-based primarily soils, which can be challenging for tomato plants due to drainage issues. Therefore, adding organic matter to the soil before planting can help loosen the soil and improve drainage.
Sunlight Tomato plants require at least 6-8 hours of sunlight daily to thrive. With Wisconsin’s varied weather patterns, monitoring the amount of sunlight your plants receive to ensure they’re getting sufficient light is essential.

Understanding Wisconsin’s climate is essential in planning your tomato planting timeline. With factors such as temperature, frost dates, soil, and sunlight influencing your decision, having a solid grasp of these conditions will help you achieve a successful tomato harvest.

Determining the Best Time to Plant Tomatoes in Wisconsin

Wisconsin’s climate and geography can vary greatly, so it’s crucial to determine the ideal planting dates for your region. The state can generally be divided into three growing zones: the northernmost area (Zone 3), the central region (Zone 4), and the southernmost area (Zone 5).

In general, your specific region’s outdoor tomato planting in Wisconsin should begin after the last frost date. Zone 3’s earliest planting date is typically mid to late May, while Zones 4 and 5 can usually begin planting in early to mid-May. However, it’s important to note that these are just general guidelines, and weather patterns can vary from year to year. It’s always a good idea to consult a local extension service or reputable gardening source for specific advice based on your location and current weather trends.

Indoor tomato planting is also famous for Wisconsin gardeners who want a head start on the growing season. Typically, seeds should be started indoors six to eight weeks before the last frost date in your area. This allows for a robust and healthy plant when it’s ready to be transplanted outdoors.

Early-Season Tomatoes

If you’re looking to plant early-season tomatoes, aim for the earliest planting date after your region’s last frost date. Early-season varieties typically mature in 50 to 70 days and are generally smaller in size than mid- or late-season varieties. They can be an excellent option for gardeners who want to enjoy an early tomato harvest.

Mid-Season Tomatoes

Mid-season tomatoes are the most popular among Wisconsin gardeners. They typically mature in 70 to 80 days and produce medium to large-sized fruit. Mid-season varieties can be a good choice for those looking to balance yield and flavor.

Late-Season Tomatoes

If you’re willing to wait longer for your tomato harvest, late-season varieties may be the way to go. These tomatoes mature in 80 to 100 days and produce large to extra-large fruit. Late-season tomatoes are an excellent option for gardeners who prioritize flavor over yield.

Preparing Your Wisconsin Garden for Tomato Planting

Before planting tomatoes, it’s essential to prepare your garden correctly. Follow these tips to maximize your tomato plants’ growth and yield:

Soil Preparation

Tomatoes require well-draining, nutrient-rich soil with a pH range of 6.0 to 7.0. Before planting, test your soil and adjust the pH level if necessary. Add organic matter such as compost or aged manure to improve soil fertility and structure. Avoid planting tomatoes in soil that has recently hosted nightshades (such as peppers or eggplants), as they can share soilborne diseases.

Sunlight Requirements

Tomatoes require at least 6 to 8 hours of direct sunlight per day. Choose a spot in your garden with ample sunlight and adequate space for tomato plants to grow. Avoid planting tomatoes in shady areas or near tall trees that can block sunlight.


Tomatoes require proper spacing to ensure good air circulation and reduce the risk of diseases. Space determinate tomato plants 2 to 3 feet apart and indeterminate tomato plants 3 to 4 feet apart. For staked or caged plants, space rows 3 to 4 feet apart.

Watering Techniques

Tomatoes require consistent and deep watering throughout the growing season, about 1 to 1.5 inches per week. Avoid overhead watering, which can promote fungal diseases. Instead, water directly at the plant base using drip irrigation, soaker hoses, or a watering can.


Mulching can help conserve soil moisture, suppress weeds, and regulate temperature. Apply 2 to 3 inches of organic mulch around tomato plants, such as straw, leaves, or grass clippings. Avoid using non-organic mulches, such as rocks or plastic, which can interfere with soil moisture and temperature regulation.


Tomatoes require regular fertilization to support healthy growth and fruit production. Use a balanced fertilizer with a ratio of 10-10-10 or 14-14-14 or a high-phosphorus fertilizer with a ratio of 5-10-10. Apply fertilizer according to the package instructions, typically once or twice a month, and avoid over-fertilizing, which can lead to excessive foliage growth at the expense of fruiting.

Pest Management

Tomatoes can attract various pests, such as aphids, tomato hornworms, and whiteflies. Use natural pest control methods, such as handpicking, spraying with insecticidal soap or neem oil, or growing companion plants that repel pests, such as basil or marigolds. Monitor your plants regularly for signs of pests and deal with them promptly to prevent severe damage.

Selecting the Right Tomato Varieties for Wisconsin

Several factors must be considered when selecting tomato varieties that will perform well in Wisconsin.

  1. First, choosing disease-resistant tomato plants is essential, as Wisconsin’s humid summers can create conditions that encourage fungal diseases such as blight.
  2. Some of the top disease-resistant tomato varieties that perform well in Wisconsin include “Celebrity,” “Legend,” and “Park’s Whopper.”
  3. Choosing tomato plants with a growth habit that fits your gardening space is also essential. Determinate tomatoes, which grow to a set size and produce fruit all at once, are a good choice for small gardens or containers.
  4. Indeterminate tomatoes, which grow and produce fruit throughout the season, require more space and support.
  5. Flavor profile is another factor to consider when selecting tomato varieties. Some of the most popular and flavorful tomato varieties that do well in Wisconsin include “Cherokee Purple,” “Brandywine,” and “Sun Gold.”
  6. Finally, choosing tomato varieties that are well-suited for the Wisconsin climate is crucial.

Early-season tomatoes, such as “Early Girl,” are ideal for areas with shorter growing seasons, while mid-season tomatoes, such as “Big Boy,” perform well in areas with moderate growing seasons.

Late-season tomatoes like “Black Krim” are best for areas with long growing seasons.

By considering these factors, you can choose the tomato varieties that are best suited for your Wisconsin garden and ensure a successful, healthy harvest.

Starting Tomatoes Indoors in Wisconsin

Starting tomatoes indoors is an excellent way to get a head start on the growing season in Wisconsin. Here are the steps to follow:

  1. Choose the suitable tomato variety: Look for varieties with a shorter maturity time, such as early ripening or determinate varieties.
  2. Gather Supplies: You’ll need a seed starting mix, seedling trays, grow lights, a watering can, and tomato seeds.
  3. Plant Seeds: Fill the seedling trays with seed starting mix and plant one or two seeds per cell. Cover lightly with soil and water gently.
  4. Provide Proper Light: Tomato seeds need at least 12 hours of light daily. If you don’t have a sunny window, use grow lights to provide the necessary light. Keep the light about 2 inches from the seedlings.
  5. Keep Soil Moist: Check the soil daily and water gently when needed. Avoid overwatering, which can cause damping-off disease.
  6. Transplant Seedlings: Once the seedlings have developed their first set of true leaves, transplant them into larger containers. Use a high-quality potting mix and keep the soil moist.
  7. Harden Off Seedlings: A week or two before planting outside, start to harden off the seedlings. This means gradually exposing them to outdoor conditions by placing them outside for a few hours each day, gradually increasing the time spent outside.
  8. Plant Seedlings: Once the danger of frost has passed and the soil has warmed up, it’s time to plant your seedlings outside. Select a sunny spot in your garden and space the seedlings at least 2 feet apart.

Starting tomatoes indoors in Wisconsin can give you a jump start on the growing season and a head start on tomato production. Following these simple steps, you’ll be on your way to growing healthy, productive tomato plants in your Wisconsin garden.


Directly planting tomatoes in your garden is straightforward and convenient, but it requires careful consideration of the ideal timing, soil conditions, and potential frost risks.

Choosing the Right Time for Direct Planting

The best time to directly plant tomatoes in Wisconsin varies depending on your region’s climate. In southern Wisconsin, planting can start as early as mid-May, while in northern Wisconsin, it’s better to wait until late May or early June. Before planting, ensure the soil temperature has reached at least 60°F and the threat of frost has passed.

Preparing Your Soil

Tomatoes thrive in well-draining, nutrient-rich soil with a pH of 6.0 to 6.5. Before planting, dig a hole twice the size of the plant’s root ball and amend the soil with compost or well-rotted manure to improve its texture and fertility. Avoid planting tomatoes in soil that has previously grown nightshade family plants, including peppers and eggplants, to reduce the risk of soil-borne diseases.

Planting and Care

When planting tomatoes, start by removing the lower leaves and planting the tomato deep enough that only the top two sets of leaves are above the soil level. This will encourage additional roots and increase the plant’s stability. Tomatoes need at least six hours of direct sunlight daily and consistent moisture to grow well.

It’s essential to support your tomato plants, as they grow tall and heavy and may break under their weight. This can be done using cages, stakes, or trellises. Regularly check for pests and diseases and take immediate action if necessary.

Protecting from Late Frosts

Even if the threat of frost has passed, Wisconsin’s unpredictable weather may still present a risk to your tomato plants. To protect them, consider covering them with row covers or blankets overnight when temperatures dip below 50⁰F. You can also use water jugs or other thermal mass materials to keep the plants warm.

Following these tips, you can grow delicious and healthy tomatoes directly in your Wisconsin garden.

Caring for Tomato Plants in Wisconsin

Once your tomato plants are in the ground, they require proper care to ensure healthy growth and abundant harvests. Here are some essential tips for taking care of your tomato plants in Wisconsin:

Watering Fertilizing Staking Pruning
Tomato plants require consistent moisture to thrive, but over-watering can lead to disease and other issues. Water deeply once a week or whenever the top inch of soil feels dry. Fertilize your tomato plants with a balanced fertilizer once a month, starting a month after planting. Avoid high-nitrogen fertilizers, as they can lead to excessive foliage growth at the expense of fruit production. Staking or caging your tomato plants is essential to support the heavy fruit load and prevent the plants from sprawling on the ground. Stake or cage your plants when planting, and adjust the support as the plants grow. Pruning your tomato plants can promote better airflow, reduce diseases, and increase fruit size and quality. Pinch off the suckers (the growth that emerges between the main stem and the branches) when small, and remove the lower leaves as the plant grows to improve air circulation.

In addition to the above care tips, it’s also important to be vigilant about pest management. Watch for common tomato pests, such as tomato hornworms, and use organic control methods whenever possible.

With proper care and attention, your Wisconsin tomato plants should produce a bountiful harvest of delicious fruit.

Harvesting Tomatoes in Wisconsin

When it comes to harvesting tomatoes in Wisconsin, timing is vital. Tomatoes should be left on the vine until they are fully ripe for the best flavor and texture. In general, tomatoes are ready to be harvested when they have reached their mature size and have developed their characteristic color. For most tomato varieties, this means they will be firm to the touch but slightly yielding, and the skin will have a deep, rich hue.

It’s important to note that tomatoes will continue to ripen after they have been picked, so if you need to harvest them before they are fully ripe, you can place them on a windowsill or other sunny spot to finish the ripening process. Just be careful not to let them over-ripen, which can lead to mushy or mealy tomatoes.

To harvest tomatoes, grasp the fruit firmly and gently twist it off the stem. Be careful not to pull too hard or crush the tomato, damaging the fruit and reducing its shelf life.

If you have a large tomato harvest, you can store them in a cool, dry place such as a pantry or garage. Alternatively, you can preserve them using canning, freezing, or drying methods. Just be sure to follow proper food safety guidelines and use high-quality tomatoes for the best results.

Troubleshooting Common Tomato Planting Issues in Wisconsin

While growing tomatoes in Wisconsin can be a rewarding experience, it’s not uncommon to encounter a few challenges along the way. In this section, we’ll address some common tomato planting issues and provide solutions to help you overcome them.


Tomatoes are susceptible to various disease problems, hindering plant growth and yield. Diseases like Early Blight, Late Blight, and Septoria Leaf Spot are common in Wisconsin. These diseases manifest as brown spots on the leaves, stems, and fruit, leading to plant death if left untreated.

Practice good sanitation by removing plant debris and infected leaves to prevent disease. Consider applying fungicides and disease-resistant tomato varieties.


In addition to diseases, pests like aphids, cutworms, tomato hornworms, and flea beetles can attack your tomato plants. These insects can cause damage, such as chewed foliage and stunted growth, leading to lower yields.

To control pests, consider using insecticidal soaps, neem oil, or natural predators like ladybugs. You can also use floating row covers to block pests from reaching your plants.

Nutrient Deficiencies

Tomatoes require specific nutrients to grow optimally, such as nitrogen, phosphorus, and potassium. A lack of these nutrients can manifest as yellow leaves, stunted growth, and poor fruit production.

To prevent nutrient deficiencies, ensure your soil is rich in organic matter and apply balanced fertilizer according to your soil test results.

Environmental Stress

Extreme temperatures, drought, and overwatering can all stress your tomato plants, leading to slower growth and lower yields.

To prevent environmental stress, ensure adequate water and shade during hot temperatures. Mulch around your plants to retain moisture and regulate soil temperature.

With these tips, you’ll be better equipped to handle common tomato planting issues in Wisconsin and ensure a successful harvest.

Extending the Tomato Growing Season in Wisconsin

While Wisconsin’s climate challenges growing tomatoes, extending the growing season and enjoying fresh tomatoes well into fall is still possible. Here are some tips and strategies to help you maximize your tomato harvest:

  1. Select cold-tolerant varieties: Choose tomato cultivars known for their cold tolerance. These varieties can survive lower temperatures and produce fruit even when the weather cools. Look for cultivars like ‘Siberian,’ ‘Polish Linguisa,’ or ‘Stupice.’
  2. Protect against frost: As the weather starts to cool, keep an eye on the forecast and be prepared to protect your tomato plants from frost. Covering them with blankets, tarps, or other protective materials can help keep them warm and prevent frost damage.
  3. Use season extenders: Consider using row covers, cold frames, or hoop houses to create a warmer microclimate around your tomatoes. These structures can trap heat and keep your plants warmer, allowing them to continue producing fruit even as the weather cools.
  4. Provide proper mulching: Mulching your tomato plants can help regulate soil temperature and protect the roots from cold temperatures. Use materials like straw, leaves, or grass clippings to create a layer of insulation around the base of your plants.

By implementing these strategies, you can extend your tomato growing season in Wisconsin and enjoy fresh, delicious tomatoes well into the fall.

Conclusion: When To Plant Tomatoes In Wisconsin?

As we conclude this comprehensive guide, we hope it has provided you with valuable insights and practical tips for growing delicious, juicy tomatoes in your Wisconsin garden.

By understanding the climate and conditions unique to your region, selecting suitable tomato varieties, and following proper planting and care techniques, you’ll be well on your way to a bountiful harvest.

Remember that growing tomatoes is a rewarding but ongoing process that requires patience, diligence, and care. However, the satisfaction of seeing your plants thrive and tasting the fruits of your labor is well worth the effort.

Whether you’re a seasoned gardener or a novice, we encourage you to experiment, be creative, and enjoy the process of growing tomatoes. With the right mindset and tools, you can overcome challenges and achieve a successful and delicious tomato harvest.

FAQ about When To Plant Tomatoes In Wisconsin?

When is the best time to plant tomatoes in Wisconsin?

The optimal time for planting tomatoes in Wisconsin is typically after the last spring frost, usually between mid-May and early June.

How does Wisconsin’s climate affect tomato planting?

A: Wisconsin’s climate has a significant impact on tomato growth. Understanding factors such as average temperatures and frost dates can help you determine the ideal planting dates for your tomatoes.

How do I determine the best time to plant tomatoes in Wisconsin?

The recommended time for planting tomatoes in Wisconsin depends on whether you’re starting them indoors or directly planting them in your garden.

How should I prepare my Wisconsin garden for tomato planting?

Mix several inches of compost or other organic material to improve drainage and nutrients to prepare your garden beds. Tomatoes need at least 6-8 hours of sunlight daily. Install cages or trellises before planting if staking plants.

What are the best tomato varieties for Wisconsin?

Some top varieties for Wisconsin are Early Girl, Celebrity, Park’s Whopper, and Beefmaster. Look for compact determinate types that mature quickly for the shorter season.

How do I start tomatoes indoors in Wisconsin?

Start seeds indoors 6-8 weeks before outdoor planting. Use a seed starting mix and grow lights if needed. Harden off plants for 7-10 days before transplanting.

Can I directly plant tomatoes in my Wisconsin garden?

You can directly sow some varieties in late May or early June. Quick maturing determinate types are best. Harden off transplants first if started indoors.

How do I care for tomato plants in Wisconsin?

Water 1-2 inches per week. Use mulch to retain moisture. Stake or cage plants. Prune suckers for best fruit production. Fertilize lightly with a tomato fertilizer. Watch for common pests and diseases.

When and how do I harvest tomatoes in Wisconsin?

Start harvesting tomatoes when they reach the desired color but are still firm. Gently twist vine-ripened tomatoes off the vine. Cut off clusters of unripe fruit at season end.

How can I extend the tomato growing season in Wisconsin?

Choose short-season varieties, start plants indoors early, use cloches/row covers to protect from frost, and harvest green tomatoes before frost to ripen indoors.

Leave a Comment