About Sowplot

Sowplot is a small reference site for people starting seeds indoors without a greenhouse: a calendar that works from your own frost date, and guides to the equipment that decides whether a tray makes it to planting out.

How the calendar works

Every sowing date is arithmetic: your last spring frost date minus the weeks a crop needs indoors. The windows come from standard extension-service guidance for each crop; the frost date comes from you. USDA zone presets are offered as a shortcut and are labelled approximate, because a zone spans hundreds of miles and a frost date does not.

What we do and do not claim

We describe methods and trade-offs, not test results. Where a number appears — weeks before frost, cell counts, temperatures — it is general horticultural guidance rather than a measurement taken in our own garden, and your local extension office is the better authority for your specific area.

Affiliate links

Some product links are affiliate links, marked as sponsored. If you buy through one, we may earn a commission at no extra cost to you. Recommendations are based on what the job needs — a covered tray, a heat mat, a light — not on commission rates.

Contact

Questions or corrections: [email protected].