When to Start Seeds Indoors (Calendar by Crop)

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Starting seeds at the right time is the difference between sturdy seedlings and tall, tired ones. The trick is to count backward from your last frost date.

Step 1: find your average last frost date

This is the typical date after which frost becomes unlikely in your area. Your local cooperative extension service, or a frost date lookup tool for your zip code, will give you an estimate. It is an average, not a guarantee, so keep an eye on the forecast too.

Step 2: count back by crop

Seed packets usually say how many weeks before the last frost to start seeds indoors. The table shows common ranges, with example dates if your last frost date is May 1. Move all dates earlier or later to match your own date.

These are general guidelines. Follow your seed packet for each variety. Gardeners in the Southern Hemisphere should count from their own spring frost dates in the same way.

Do not start too early

It is tempting to sow everything in January, but seedlings that outgrow their cells get root-bound and stressed. If the weather is not ready, you end up with plants waiting indoors. When in doubt, start slightly later rather than earlier.

Plan for hardening off

Build in a week or two before the planting-out date to harden off seedlings gradually. That first outdoor exposure should be a few hours in partial shade, then longer and sunnier each day.