To grow tomatoes for a fall harvest, count back from your first fall frost date by the variety’s days to maturity, your harvest window, and two 14-day allowances for slower fall growth and frost. A 70-day tomato with a 3-week harvest and a November 15 frost needs to be transplanted by about July 19. Enter your dates below.
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What Your Result Means: the transplant-by date is the latest date to set plants out and still get your harvest before frost. Planting a week or two earlier gives a margin for a cool fall or an early frost. If you start from seed, sow by the seed date shown. The tool also compares the date with today and tells you whether there is still time.
When Should You Plant Tomatoes for Fall?
Work backward from your average first fall frost. The plant needs time to mature, time for you to harvest, extra time because autumn growth is slower, and a buffer so the fruit is ripe before frost.
- Find your first fall frost date from your extension office or a zip-code lookup.
- Enter days to maturity from the seed packet or plant tag.
- Choose transplants or seed, and how long you want to harvest.
- Read the transplant-by date and aim a week or two earlier for a safety margin.
What Each Result Means
| Result | What It Tells You |
|---|---|
| Transplant by | The latest date to set plants out |
| Start seeds by | The latest sowing date if you grow your own |
| Days counted back | How the date was worked out |
| Time check | Whether there is still time this year |
| Longest variety that fits | The slowest variety you can still plant today |
Fall Tomato Count-Back Chart
Days to count back from the first fall frost for transplants with a 3-week harvest (days to maturity + 21 + 14 + 14).
| Days to Maturity | Count Back | Frost Nov 15: Plant By | Frost Oct 15: Plant By |
|---|---|---|---|
| 55 (early or cherry) | 104 days | August 3 | July 3 |
| 65 | 114 days | July 24 | June 23 |
| 75 | 124 days | July 14 | June 13 |
| 85 (large or heirloom) | 134 days | July 4 | June 3 |
How Does the Fall Planting Calculator Work?
It uses the count-back method from University of Nebraska–Lincoln Extension’s fall gardening guide, which Virginia Cooperative Extension also teaches.
+ harvest period you want
+ fall factor (14 days)
+ frost-tender factor (14 days)
Transplant by = first fall frost – days to count back
Start seeds by = transplant date – 42 days (if growing your own)
It then compares your transplant date with today. If the date has passed, it works out the longest days to maturity that still fits between today and your frost.
Worked Example
Say your first fall frost averages November 15 and you want to grow a 70-day variety from bought transplants, harvesting for 3 weeks. Count back 70 + 21 + 14 + 14 = 119 days, which gives a transplant-by date of July 19. If you grew your own from seed, you would sow 6 weeks earlier, by June 7.
Factors That Change the Result
- Variety speed: each extra 10 days to maturity moves the planting date 10 days earlier; short-season types are best for fall.
- Frost date: it is an average, so an early frost can come sooner; plant with a margin.
- Summer heat: flowers tend to drop above about 90°F by day or 75°F at night, delaying fruit on midsummer plantings.
- Transplant size: larger, healthy transplants establish faster in the heat than small ones.
- Frost protection: row covers can stretch the season a little past the first light frost.
Understanding Your Outputs
| Output | Meaning | Best Used For |
|---|---|---|
| Transplant by | Latest safe planting date | Buying and planting |
| Start seeds by | Latest sowing date | Seed starting |
| Days counted back | The full calculation | Checking the math |
| Time check | Days left or days late | Deciding whether to plant |
| Longest variety that fits | Max days to maturity from today | Picking a faster variety |
When to Use It
Use it in late spring or early summer, while there is still time to plan a second crop, especially in warm regions with long falls. For spring planting, use the Planting Date Calculator. For regional timing, see our When to Plant Tomatoes guide, including Texas and Florida.
Common Mistakes to Avoid
- Using the packet days as-is: they assume long summer days; add the fall factor.
- Planting a long-season heirloom late: an 85-day variety needs planting about a month before a 55-day one.
- Forgetting seed-starting time: growing your own adds about 6 weeks before transplanting.
- Cutting it to the exact date: frost dates are averages, so leave a margin.
- Neglecting midsummer transplants: water them well and give light shade for the first days in heat.
Accuracy and Limitations
This is a planning estimate based on averages.
What It Does Well: applies the standard extension count-back method and flags when it is too late for a variety.
What It Does Not Do: predict your actual frost or weather. A hot summer, cool fall, or early frost will shift results. The seed-starting step assumes about 6 weeks; allow up to 8 for larger transplants. This is general guidance, not professional advice.
Methodology
Method: the fall count-back formula from University of Nebraska–Lincoln Extension NebGuide G1343: days from transplanting to harvest, plus seed-to-transplant days if you grow your own, plus the average harvest period, plus a fall factor of about 14 days, plus a frost-tender factor of 14 days for frost-sensitive crops such as tomatoes, counted back from the first expected fall frost. Virginia Cooperative Extension publication 426-334 teaches the same method. Seed-to-transplant: 42 days (6 weeks), matching our Planting Date Calculator’s 6 to 8 week range. Heat note: blossom drop thresholds match our other tools. Dates: calculated in your browser from the date you enter; today’s date comes from your device.
Sources: University of Nebraska–Lincoln Extension – Fall Vegetable Gardening (G1343), Virginia Cooperative Extension – Fall Vegetable Gardening (426-334). Last reviewed: September 28, 2026 · Reviewed by Aiza Anwar.
Frequently Asked Questions
When should I plant tomatoes for a fall harvest?
Count back from your average first fall frost date. Add the variety’s days to maturity, the weeks you want to harvest, about 14 days for slower fall growth, and 14 days so fruit matures before frost. For a 70-day variety, a 3-week harvest, and a November 15 frost, that means transplanting by about July 19.
What is the fall factor?
An allowance of about 14 days for the slower growth that comes with shorter, cooler autumn days, as described by University of Nebraska–Lincoln Extension. Days to maturity on seed packets assume spring and summer conditions.
What is the frost-tender factor?
Another 14 days added for frost-sensitive crops such as tomatoes, which need to mature at least two weeks before frost to give a reasonable harvest.
Which tomatoes are best for fall planting?
Short-season, early-maturing varieties, since they finish before frost. Cherry types are also quick. Nebraska Extension notes mid-summer plantings of short-season cultivars can give vigorous plants and high-quality fruit.
Can I start fall tomatoes from seed?
Yes, but add the 6 to 8 weeks it takes to grow a transplant, which pushes seed starting into early summer. Buying transplants saves that time.
Will fall tomatoes set fruit in summer heat?
Flowers often drop when days are above about 90°F or nights stay above about 75°F, so plants set in midsummer may not set fruit until the weather eases. Plan for that by planting on time rather than late.
What if my planting date has already passed?
Choose a faster variety. The calculator shows the longest days to maturity that still fits before your frost date. If nothing fits, grow cherry tomatoes in containers you can move indoors, or wait for spring.
What happens to green tomatoes at frost?
Pick all mature green and colored fruit before a frost. Mature green fruit ripens indoors at about 65 to 70°F in one to two weeks.
Where do I find my first fall frost date?
Your local extension office or a frost-date lookup by zip code gives the average first fall frost. It is an average, so watch the forecast as it approaches.
Related Tomato Tools
See When to Plant Tomatoes
This calculator gives planning estimates from average frost dates, not a guarantee. Weather varies year to year; watch the forecast as your frost date approaches. Spotted an error? Tell us here.