How to use the succession planting schedule generator
- Enter the first sowing date and the days between sowings.
- Enter the days from sowing to harvest for your crop, from the seed packet or your own records.
- Enter the last day you can harvest, such as the date you expect a frost or when the bed is needed for something else.
- Read the number of sowings and the table of sowing and harvest dates. Add a harvest window under Advanced options to see how long each sowing stays harvestable.
Formula
last sowing that fits = last harvest day - days to harvest (- harvest window)
number of sowings = floor((last sowing - first sowing) / days between sowings) + 1
sowing k = first sowing + (k - 1) x days between sowings
Sowings are spaced evenly from the first date. A sowing counts only if its harvest finishes by the last harvest day, so the final sowing may fall before the last sow-by day by up to one gap.
Lettuce every two weeks from mid April
Starting on Thursday, April 15, 2027, sowing every 14 days, with 50 days to harvest and a last harvest on September 30, the last day a sowing can fit is Wednesday, August 11 (50 days before). That is 118 days after the start, and 118 divided by 14 gives 8 whole gaps, so there are 9 sowings.
The first is ready from Friday, June 4 and the ninth sowing, on Thursday, August 5, is ready from Friday, September 24. If each planting stays harvestable for 14 days, the last sow-by day moves 14 days earlier and the plan has 8 sowings. A leap year changes nothing in the method, and a plan from February 1 to April 30, 2028 with 7-day gaps and 30 days to harvest gives 9 sowings.
Why sow in succession
Planting a crop all at once gives you a glut and then nothing. Sowing a little at regular intervals spreads the harvest across the season. The right gap depends on how much you can eat or sell, how long a planting stays good in the garden and how fast your crop matures.
Some crops grow poorly in the heat of summer or in short days, so the dates are best used as a starting plan. Adjust as the season shows how fast things grow.
Next steps
To work from your last frost date and choose when to start seeds indoors, use the Planting Schedule Calculator. For how far apart to place plants, the Plant Spacing Calculator gives counts per bed, and the Growing Degree Days Calculator tracks heat for crops that mature by warmth rather than days.
More garden and craft tools
For sprinklers, water changes and sewing, try the Sprinkler Layout and Spacing Calculator, Aquarium Water Change Calculator and Tote Bag Cutting Dimensions Calculator.
Assumptions and limits
- Days to harvest is a fixed number for every sowing, ignoring the season's effect on growth.
- The gap between sowings is constant, and the first sowing is on the date you enter.
- Dates follow the Gregorian calendar and the leap years are included.
- A plan can have up to 120 sowings.
- The example dates are an illustration. Replace them with your own.
Frequently asked questions
What if my crop gets faster as the weather warms?
Then the real harvest dates will come earlier than the table shows. Use the table to plan, and note actual dates to improve the numbers next year.
Does the plan work for crops that are transplanted?
Use the days from sowing the seed to harvest. If you start seedlings indoors, count from the day you sow the seed, or use the planting date and days from transplant.
What does the harvest window do?
It lets a planting stay harvestable for some days after it is ready, such as a crop that holds in the field. That shifts the last sow-by day earlier.
Why does the last sowing not land exactly on the last sow-by day?
Sowings are spaced evenly from the first one, so the last falls on or before the sow-by day, within one gap of it.