Sowing & Transplanting Scheduler

A frost date is a probability

The published last-frost date is the one frost has passed by in half of years: a coin flip, not a deadline. A 10 percent date is much safer for tender crops.

Counting backwards

Weeks before last frost:

Crop	Sow indoors
Onions and leeks	10 to 12 weeks
Peppers and aubergines	8 to 10 weeks
Tomatoes	6 to 8 weeks
Brassicas	4 to 6 weeks
Cucumbers and squash	2 to 4 weeks

Sowing earlier produces root-bound seedlings, which are routinely outgrown by ones sown weeks later. Soil temperature beats the calendar; beans and squash rot below 60 °F.

Some crops should not be transplanted

• Direct sow: carrots, parsnips, beetroot, radish, turnips. Roots fork if disturbed.
• Careful: cucumbers, squash, melons, beans. Plant them pot and all.
• Happily transplanted: tomatoes, peppers, brassicas, lettuce, onions.

Tomatoes root along a buried stem, so plant leggy ones deep. Harden everything off over seven to ten days.

Days to maturity counts from different places

For transplanted crops the packet counts from transplanting, so a 75-day tomato is really 75 plus its weeks as a seedling. Add two more weeks for autumn crops, as everything slows with the daylight.