Planting decision
When do I sow the next round?
Enter a ZIP code. This works out how often each crop is worth re-sowing, when your next sowing is due, and — where summers are hot enough to matter — which sowings in the middle of the year are not worth making.
How this decides
A succession run has two ends, and both come from your own freeze dates. It opens at the point the crop can first go in — the same published offset from your last spring freeze that the seed-starting calendar uses. It closes at the last sowing whose days-to-maturity still land inside your first fall freeze, plus whatever frost the crop can take on the end. In between, it repeats at that crop's own interval.
Why 12 of these 32 crops are missing
Every printable succession chart applies one fortnight to everything on it. That is wrong for 12 of the 32 crops here, so they are left out rather than given an interval. Tomatoes, peppers, zucchini and okra keep producing for months from a single planting. Kale and chard are cut leaf by leaf from one sowing. Re-sowing any of them is wasted seed and a wasted bed — the honest answer is "sow this once", and it is a different answer from "no data".
The 20 that remain each carry their own interval. Radishes come round every 10 days; carrots every three weeks. A single blanket number would be wrong at both ends.
Where summer stops the run
In a hot climate the middle of the window is unusable for anything that bolts. Sowing lettuce every fortnight through a Phoenix July is a chart instruction that costs you a summer of seed. Where the mean summer high reaches 90 °F, sowings that land in June, July or August are held back for crops rated as bolting, and the run picks up again for autumn.
That hold is bounded to exactly June–August because that is the period the underlying measurement covers — NOAA publishes a mean daily high for those three months, and stretching the claim into May or September would be inventing coverage the figure does not have.
A limit worth knowing. That 90 °F threshold is a summer average, so it identifies genuinely hot places and not merely warm ones. A cooler-summer garden can still bolt a July lettuce in a heatwave, and no sowing will be held back here for it. The hold is a floor under the advice, not a promise about your season.
The intervals and the bolting ratings are a judgement — conventional extension guidance, and they vary by variety. The freeze dates the window is cut from are measured, and every result names the station they came from and how far away it is. Heat never moves a sowing date on this page; it only marks one as not worth making.
The rest of the year
This tool is for a season already underway. For its opening, see when do I start my seeds? For its close — the growing days left and what still has time to mature — see what can I still plant? For the things that are not sown each year at all, see what survives my winter?