About the Harvest Date Calculator
This harvest date calculator predicts when a crop will be ready to pick. Choose a vegetable from the list (or enter the days to maturity from your seed packet), set the date you sowed or transplanted it, and the tool counts forward to give the expected first harvest date, the end of the picking window and how many days away it is.
It helps gardeners plan around holidays and frost dates, market growers schedule harvests for a given week, and anyone running succession plantings — sowing a new batch of lettuce, beans or radishes every couple of weeks so the harvest is continuous instead of all at once. Set the number of plantings and the interval, and the table lists every sowing and harvest date.
Days to maturity is an average for good conditions. For crops normally transplanted (tomatoes, peppers, broccoli) the figure counts from transplanting, so add about 2–6 weeks if you direct-sow them. Cool weather, short autumn days and poor soil slow growth, so use the extra-days field to pad the estimate, especially for fall crops.
How to use the harvest date calculator
- 1Enter the date you sowed seed or set out transplants.
- 2Pick the crop, or choose Custom and type the days to maturity from the seed packet.
- 3Add extra days for cool weather, fall planting or direct-sowing a transplant crop.
- 4Set how long the harvest lasts and, for successions, how many plantings and how far apart.
- 5Read the first harvest date and use the schedule table to plan sowings.
Formula and method
The calculator simply counts calendar days forward from the planting date. Days to maturity is the seed company’s average number of days from sowing (or from transplanting, for crops normally started indoors) until the first harvest under good growing conditions. Any extra days you enter — for cool weather, short fall days or direct-sowing a transplant crop — are added on top.
For succession planting, each new sowing is offset by the interval, and every planting gets the same days to maturity and harvest window. The harvest window is how long the crop keeps producing once it starts; it varies from a few days for radishes and sweet corn to many weeks for tomatoes, beans picked regularly and zucchini.
- Days to maturity
- Average days from sowing or transplanting to first harvest
- Extra days
- Padding for slower growth conditions
- Interval
- Days between succession sowings
Worked examples
Tomato transplanted on April 15
A 70-day tomato set out on April 15, 2026 should give its first ripe fruit around Wednesday June 24. With a 21-day window entered, the main picking runs to about July 15 (indeterminate varieties keep going much longer).
Four lettuce sowings two weeks apart from March 20
Leaf lettuce takes about 45 days, so the first sowing is ready May 4. Sowing again every 14 days, the fourth sowing goes in May 1 and is ready June 15, so salad keeps coming until about July 6.
Custom 95-day variety with 10 extra days
A 95-day variety plus 10 days of padding is 105 days. Counting forward from May 10, 2026 lands on Sunday August 23.
Frequently asked questions
What does days to maturity mean on a seed packet?+
It is the average number of days from planting until the first harvest under good conditions. For crops usually direct-sown it counts from sowing; for crops normally transplanted, such as tomatoes and peppers, it counts from setting transplants in the garden.
Why is my harvest later than the seed packet says?+
Days to maturity assume warm, sunny weather and fertile soil. Cool nights, cloudy spells, short autumn days, drought and crowding all slow growth, so fall crops in particular often take 1–3 weeks longer.
How do I calculate the last planting date before frost?+
Count backward from your average first fall frost by the days to maturity plus about two weeks for the slower fall growth (the “fall factor”), and add the harvest window you want. Use the planting schedule calculator for frost-based dates.
How often should I succession plant?+
Fast crops such as lettuce, radishes, spinach and cilantro are usually sown every 1–3 weeks, while bush beans and sweet corn are sown every 2–3 weeks. Stop when the next sowing would not mature before frost or summer heat.
How do I know a crop is actually ready?+
Use the date as a cue to start checking. Look for full color and size, a slight give in tomatoes, dry silks and milky kernels in sweet corn, a hollow sound in watermelon and filled pods in beans and peas.