Succession Planting Calculator
Six staggered sow-and-harvest date pairs from a start date and interval, turning one glut into a season of steady harvests.
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Harvest Date Calculator
Add days to maturity to a planting date for a calendar harvest date, with the margin left before first fall frost.
Harvest Date Calculator
Chlorova · updated for 2026
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Click “Calculate” to see your results.
Days to maturity are nursery conventions counted from transplant for setting crops and from sowing for direct-seeded ones, and they describe first harvest under ideal warmth, not your weather. Cool springs, heat waves that stall pollination and variety drift all slide the real date by one to two weeks, so treat the answer as the middle of a window. Frost dates are likewise averages, meaning roughly a one-in-three chance your first frost lands earlier than the number, which is what the tight-margin band is there to warn about.
Seed packets speak in days, but gardeners plan in dates, and the translation between them is one addition and one subtraction. This calculator adds a crop's days to maturity to your planting date and hands back the actual calendar day you should expect to be harvesting, then measures how much frost-free room that projected date leaves before your first fall frost. It is the sanity check that stops a July tomato transplant from quietly becoming a September confession instead of a late harvest.
Projecting the Calendar in Steps
- Choose the crop you are planting or setting out this week.
- Enter the real calendar date the seed or transplant goes into the ground.
- Add your area's average first fall frost date from the almanac.
- Read the expected harvest date printed at the top of the results.
- Note the weeks-to-harvest figure for bench and market planning.
- Check the frost margin, the days left between harvest and frost.
- Read the season verdict band before you commit the bed.
- Shift the planting date a week later to test the worst case.
- Swap crops to compare a fast bean against a slow tomato.
Dates as Numbers, One Addition Each
Behind the scenes every date is a day count, so the harvest projection is simply planting serial plus the crop's maturity days, and the page converts that number back into a calendar date like July 29. A week figure rides alongside because nursery timing talk is weekly, and garden centers plan transplant benches in sevens.
The frost question is a subtraction: first fall frost date minus projected harvest gives the margin in days, and the verdict band reads that margin the way a market gardener would. Anything below two weeks past frost is a crop that will not finish outdoors, a slim positive margin means row cover and hope, and three frost-free weeks of cushion is what comfortable planning feels like.
Worked Example: A Memorial Day Tomato Transplant
- Set the crop to tomato and the transplant date to May 15.
- The packet figure is 75 days to ripe fruit from transplant.
- Adding those 75 days lands the harvest on July 29.
- That is roughly 10.7 weeks, the bench-planning figure.
- Enter September 30 as your average first fall frost.
- July 29 to September 30 leaves a 63-day margin.
- The verdict band calls that comfortable, no cover needed.
- Planting three weeks later instead on June 5 slides harvest to August 19.
- A July 10 sowing would land September 23, tight with cover ready.
- Every later date eats the margin seven days at a time.
Days to First Harvest
The maturity figures this calculator applies, counted from transplant for setting crops and from seeding for beans, matching common seed-packet conventions. Varieties routinely swing ten days either side, and fruiting crops stall entirely when night temperatures stay below about fifty-five degrees.
| Crop | Days | Counted from | Real-world swing |
|---|---|---|---|
| Tomato | 75 | Transplant | Cherries early, beefsteaks late |
| Sweet pepper | 70 | Transplant | Color adds ten days |
| Broccoli | 60 | Transplant | Side shoots continue |
| Bush bean | 60 | Direct seed | Heat accelerates, cool delays |
| Cucumber | 55 | Transplant or seed | Slicers run a week longer |
| Summer squash | 50 | Direct seed | Production spans weeks |
Key Terms
- Days to maturity
- The packet's count from planting to first harvest under ideal conditions.
- Transplant
- A starter plant set into the garden, the starting line for fruiting-crop counts.
- First fall frost
- The average date of the season's killing freeze, the deadline tender crops plan against.
- Frost margin
- Days between expected harvest and first frost, the measure of a plan's safety.
- Maturity window
- The realistic span around the packet date, typically plus or minus two weeks.
How Market Farmers Project Harvests
- Farmers plan in windows, not dates, because a packet's 75 days is honest only at ideal temperature, and a cool June can stretch a tomato to 90 while a hot July compresses beans to 50.
- Night temperature is the pause button on fruiting crops, since pollen set fails below the mid-fifties and above the eighties, which means a calendar projection is really a weather assumption.
- The fall broccoli trap is exactly the tight-margin band: transplanting late enough that heads size up into October frost works only with row cover and a variety bred for cold tolerance.
- Experienced growers reverse-plan from market dates rather than forward from planting, entering this calculator with the harvest goal and walking the planting date backward until the margin looks honest.
- Succession sowings stagger the verdict, because a new sowing every two weeks turns one risky projected date into a harvest continuum that weather cannot fully wreck.
Common Mistakes & Fixes
- Counting packet days from seed for a crop whose number is measured from transplant.
- Planning against the earliest frost you have ever seen instead of the average date.
- Treating the projected date as a single day rather than a two-week maturity window.
- Assuming determinate and indeterminate tomatoes finish on exactly the same clock.
- Letting a July transplant project past the frost line and then changing neither the date nor the crop.
- Forgetting that bolted greens and oversized squash still pick from the same calendar you planned.
When to Use This (and When Not To)
Use it any time you hold a transplant flat or seed packet in May and need to know whether the season actually has room, and again in July before that tempting second planting. For interval-based sowings rather than single crops, the succession-planting calculator lays out batches, and the frost-date tool pins the local season bounds.
Harvest Date Calculator: Frequently Asked Questions
How do I calculate harvest date from days to maturity?
Add the maturity number to the planting date, counting from transplant for tomatoes and peppers and from sowing for direct-seeded crops, and accept a two-week window around the result. That is exactly the arithmetic this page performs with your real calendar dates.
Is days to maturity from transplant or from seed?
For tomato, pepper, broccoli and other setting crops the packet counts from transplant; for beans, cucumbers and squash grown by direct seeding the count starts at germination. Mixing the two costs about three to four weeks, the most common planning error with fruiting crops.
Can I still plant tomatoes in July?
Often yes in zones with a frost later than mid-September, because a 75-day crop planted by early July finishes just inside the margin with row cover handy. Run your actual frost date through the calculator and let the verdict band make the call honestly.
Why does my garden never match the packet date?
Packet figures assume ideal temperature, moisture and fertility, and real seasons run cool or hot enough to shift first harvest one to two weeks either way. The margin bands here exist precisely because both halves of the calculation are averages.
Do frost-tolerant crops change the math?
For broccoli, kale and other hardy crops the frost date is a soft rather than hard deadline, since covered plants carry on well past the number. The verdict bands read the margin as if tender, which is the conservative and honest default for mixed plantings.
How far ahead can I plan a harvest?
Roughly a full season with confidence, because the arithmetic is exact while the inputs vary two weeks either side, and weather within one month of the date can still compress or stretch picking. Longer horizons belong to variety selection more than to calendars.
Sources & Further Reading
- Days to Maturity and Harvest Planning — University of Maine Cooperative Extension. Basis for packet conventions and maturity windows.
- Home Garden Vegetables: Planting Dates — Iowa State University Extension. Source of per-crop day counts from transplant versus seed.
- Frost Dates and Fall Garden Planning — Penn State Extension. Supports frost-margin interpretation guidance.
Chlorova Gardening Team
Builds, checks and documents every tool we publish
Chlorova editorial review
Checked against extension-service publications
Formula verified against published references · Updated
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