DibbleIf you only learn two dates as a gardener, learn these: your average last spring frost and your average first fall frost. Together they define your growing season, and nearly every planting date is measured from one of them.
The last spring frost
This is the average date after which a hard freeze becomes unlikely. Tender, warm-season crops like tomatoes, peppers, and basil wait until after it to go outside. Cool-season crops like peas and spinach can go out weeks before it, because a light frost does not bother them.
The first fall frost
This is the average date when freezing nights return in autumn. It is the deadline for your warm-season harvest, and the anchor for crops you plant in late summer to overwinter, like garlic. Counting backward from this date tells you the last day it is worth sowing a fall crop.
How to use them
Find your frost dates by zone on any zone page, or see the frost dates for every state. Most states cover more than one zone, and Maine's frost dates, for example, put the last spring frost about three weeks later in the far north than on the southern coast. Remember they are averages, not guarantees. A late spring frost can still arrive after the average date, so keep an eye on the forecast and cover tender plants on a cold night. Dibble can send a frost alert the evening before a cold night, so you are not caught out. Once you have the dates, the spring garden checklist and winterizing your garden list the jobs that hang on them.
