Succession Planting Calculator
Plan continuous harvests by calculating planting intervals for succession planting throughout the season.
About this calculator
Succession planting is a widely recommended home-gardening and market-gardening technique for spreading out a single crop's harvest over most of a growing season instead of getting one large glut all at once — a common issue with crops like lettuce, radishes, bush beans, and salad greens that mature within a fairly narrow, predictable window. This calculator spaces successive plantings by the harvest window you enter — how many days each planting keeps producing — on the logic that starting the next planting just as the previous one finishes its productive window keeps harvest continuous without excessive overlap or gaps. It then works out how many of your desired plantings actually fit within your growing season: the last planting has to be started early enough that it still reaches maturity before your season-ending frost or heat, which is why the calculator caps the number of realized plantings at whatever the season length and planting interval can actually support, even if you asked for more.
This is one defensible method among several real approaches gardeners use for succession planting — some instead use a fixed calendar interval (like 'every two weeks') regardless of a specific crop's harvest window, and fast-maturing crops with very short harvest windows (radishes) versus crops that produce over many weeks (bush beans, cut-and-come-again lettuce) benefit from different spacing strategies. Local frost dates, summer heat that can cause certain cool-season crops (lettuce, spinach) to bolt, and pest/disease pressure that varies through the season aren't modeled here and should factor into your actual planting calendar alongside this estimate.
Inputs
Results
Days Between Plantings
14 days
Actual Plantings That Fit
6
How to Use This Calculator
- Enter the days to maturity from your seed packet and the harvest window — how many days each planting will produce harvestable crops.
- Enter your total frost-free growing season length in days and the number of successive plantings you want to make.
- Enter the number of seeds or transplants per planting round.
- Review the Days Between Plantings to schedule your sowing calendar evenly across the season.
- Check Actual Plantings That Fit — it may be lower than the number you requested if your season can't support them all.
- Note Total Seeds Needed and Total Harvest Weeks to plan purchases and estimate continuous supply duration.
How the result changes with Harvest Window
| Harvest Window | Days Between Plantings | Actual Plantings That Fit |
|---|---|---|
| 7 | 7 days | 6 |
| 11 | 11 days | 6 |
| 21 | 21 days | 5 |
| 35 | 35 days | 3 |
What each input means
- Days to Maturity
- Days from planting to first harvest (check seed packet).
- Harvest Window
- How many days each planting produces harvestable crops.
- Growing Season Length
- Total frost-free days in your growing season.
- Desired Plantings
- How many successive plantings you want to make.
- Seeds per Planting
- Number of seeds or transplants per planting round.
What each result means
- First Planting (day)
- Always day 0 — the start of your growing season, used as the reference point every other planting day is measured from.
- Actual Plantings That Fit
- The number of successive plantings that actually fit your growing season — may be lower than Desired Plantings, or zero if Days to Maturity exceeds the season length.
How this is calculated
Worked example, using the default values
- Identify Input Parameters5 parametersDays to Maturity = 60, Harvest Window = 14, Growing Season Length = 150, Desired Plantings = 6, Seeds per Planting = 20 = 5 input(s) provided
- Calculate Days Between PlantingsDays Between Plantings14 = 14
- Calculate First PlantingFirst Planting0 = 0
- Calculate Last PlantingLast Planting90 = 90
- Calculate Actual PlantingsActual Plantings = min(Desired Plantings, plantings that fit the season)6 = 6
Engine last updated . Checked against 1 independently-derived test — how we verify calculators. Built by Paul Gunder, a software engineer, not a licensed financial, medical, or legal professional.
Frequently Asked Questions
Why is the interval between plantings based on the harvest window instead of days to maturity?
The goal of succession planting is continuous harvest, so the key question is when the previous planting's productive period ends, not when it started. Spacing new plantings by the harvest window means each new planting's harvest begins right around when the prior one tapers off, minimizing both harvest gaps (too long an interval) and simultaneous gluts (too short an interval) for crops that produce over a defined window rather than being harvested all at once.
Why might fewer plantings fit than the number I requested?
The last planting in a season has a hard constraint: it needs enough days remaining before your season ends for the crop to actually reach maturity, so plantings can't be scheduled indefinitely close to the end of your growing season. If your desired plantings, spaced at the harvest-window interval, would push a planting's start date past that cutoff, the calculator caps the count in Actual Plantings That Fit at the maximum that genuinely fits — asking for more plantings than the season supports doesn't change the biology. If Days to Maturity is longer than your entire growing season, Actual Plantings That Fit drops to zero: even a planting started on day one wouldn't mature before the season ends.
Does this work for crops that are harvested all at once, like a single cabbage head?
Succession planting by harvest window works best for crops that produce over an extended period — cut-and-come-again greens, beans, or crops like radishes that you pick multiple times from one planting. For a crop that's essentially harvested once (a head of cabbage or a single melon), the 'harvest window' concept is less meaningful; those crops are usually staggered on a fixed calendar interval instead, which you can still model here by entering that interval as the harvest window.
How do I choose Days to Maturity if my seed packet gives a range?
Use the shorter end of the range for your last planting's maturity check (Last Planting Day), since that's the more conservative choice for making sure the crop actually finishes before your season ends — the range on a seed packet usually reflects normal variation from growing conditions, and erring toward the faster estimate reduces the risk of an unharvested crop when frost or heat arrives.
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