Harvest Date Calculator
Project a planting forward to its harvest window, from the crop’s days to harvest.
Days to harvest is the most misread number on a seed packet: it counts from transplant for some crops and from sowing for others, and it describes the first picking, not the last. This calculator applies the right count for each crop and returns the full harvest window, plus how many days are left from any date you choose, so ‘is it ready yet’ becomes a date instead of an argument.
It pairs with the Seed Starting and Planting Date Calculator: that one counts from frost to planting, this one counts from planting to picking.
How this is worked out
Harvest start = planting date plus the crop’s days to harvest. For transplanted crops the count runs from planting out, matching packet convention; for direct sown crops it runs from sowing (germination is inside the figure). The window length reflects how the crop yields: a cabbage is one cut over a week or two, a zucchini gives for six weeks if picked young, kale and chard give for months. Windows here are deliberately modest planning figures for a home bed.
Assumptions:
- Packet days assume decent conditions. Cold soil, drought or shade stretch them; the fall slowdown can add one to two weeks to anything maturing after September.
- Variety matters: an early tomato at 60 days and a beefsteak at 85 are both ‘tomatoes’. If your packet prints a different figure, trust the packet for that variety.
- First harvest is the start of picking, not peak. Most crops peak one to three weeks into the window.
Worked examples
1. Tomatoes transplanted Apr 20. Plus 70 days: first ripe fruit about Jun 29, with picking running through summer until frost decides otherwise.
2. Bush beans direct sown May 10. Plus 55 days: first picking about Jul 4, window to about Jul 25. This is the crop where a succession sowing every two weeks turns a three week window into a season.
3. Carrots sown Apr 6. Plus 70 days: mid June for the first thinnings as baby carrots, with the main crop sizing through July. Roots are the forgiving case: the window is set by the gardener, not the plant.
Reading readiness instead of the calendar
The window tells you when to start checking; the crop tells you the day. Tomatoes colour-break then soften, corn silks brown while kernels milk when pierced, melons slip from the vine and smell sweet at the blossom end, winter squash rings hollow with a rind a thumbnail cannot dent. Harvesting at first readiness, and often, also drives yield: zucchini, beans, peas, cucumbers and okra all slow down if ripe fruit is left hanging, because the plant reads it as seed made and mission complete.
Keep a one-line garden log per crop (planted, first pick, last pick). One season of your own dates corrects the packet figures for your soil and habits better than any table, including this one.
Common mistakes
- Counting tomato days from sowing. Packet tomato days run from transplant. Counting from sowing makes the crop look three weeks late and the gardener miserable for no reason.
- Waiting for the whole crop at once. Most vegetables are picked in passes. The first beans are a meal while the rest size up; holding out for a single grand harvest wastes the early passes.
- Judging by the calendar in a weird year. A cold June genuinely delays everything. If the window says ready and the fruit says green, believe the fruit and recheck in a week.
- Missing the window’s end in fall. As days shorten, unripe tender fruit stops gaining. At first frost warnings, bring in what can ripen indoors (tomatoes, peppers) rather than losing the lot.
Putting the result to work
Mark the first harvest week on the calendar when you plant, not when you remember in July. Pair it with the Succession Planting Planner for crops you want in sequence, so the next sowing’s window opens as this one closes.
When will my crop be ready to harvest?
- Pick the crop and whether it went in as a transplant or as seed.
- Enter the actual planting date.
- Read the first harvest date and the end of the main picking window.
- Use the check date to see days remaining from today.
- Start checking the crop itself a few days before the window opens.
Do days to harvest count from sowing or transplanting?
It depends on the crop, and packets follow the convention this calculator uses: for crops normally transplanted (tomatoes, peppers, brassicas, celery), the count runs from planting out. For direct sown crops (beans, carrots, corn, peas), it runs from sowing, with germination time included in the figure.
Why is my crop not ready on the calculated date?
Usually weather: the figures assume a normal season. A cold spring, a cloudy spell, drought or hungry soil can each add a week or more, and fall crops slow as days shorten. Variety is the other cause: packet figures for a species span weeks between early and late varieties.
What does the harvest window mean?
The stretch over which the crop picks well. One-cut crops like cabbage and cauliflower have short windows of a week or two. Cut-and-come-again and fruiting crops (kale, zucchini, beans, cucumbers) pick for three to six weeks or more, especially if you harvest often, which keeps the plant producing.
Can I harvest earlier than the window?
For many crops, yes, at a smaller size: baby carrots, baby beets, young zucchini and thinnings of lettuce and chard are all deliberate early harvests. Fruiting crops are the exception: an under-ripe melon or winter squash never improves, so their windows are firmer.
How do I know the real date for next year?
Log it. Note planted and first pick dates per crop for one season and your own figures replace the packet’s. Gardeners who keep that one line per crop calibrate every calculator they use, including this one.
Days to harvest and window lengths are standard planning values per crop, consistent with seed packet and US extension figures.
