when to start seed

A Way to Garden when to start seed calculatorNEED HELP remembering when it’s safe and smart to start your first spring sowings of vegetable, flower and herb seeds indoors and out? This tool helps calculate when. Begin by entering your final spring frost date on the top right of the chart below. (Don’t know? Select your state, then your nearest weather station, from this USDA chart, then slide across to 10 percent possibility at 32 degrees.)

The chart dates suggest earliest springtime sowings, but there is no hard-and-fast rule whether lettuce needs 4 or 6 weeks indoors—or if you never give it a headstart, but simply direct-sow. This is my best guidance, not doctrine; that’s why my website is “A Way to Garden,” not “The Way to Garden.”

Note: Reemay or other protective row covers can “cheat” the earliest transplant dates by as much as 2 weeks, especially helpful with tender things like melons (or insect-prone brassicas and cucurbits).

Many crops (salads, carrots, beets, bush beans, cilantro…) are best sown in succession, a small amount every 2 weeks, starting at the chart date. In some climates, a later sowing timed for fall or winter harvest (such as Brussels sprouts) may do better than a spring one, or you can get a whole second sowing in of peas that you sowed in spring, then pulled.

I’ve added a list of how-to story links below, including some on stashing your harvest. Again: Start by entering your final spring frost date below (mine’s about Memorial Day).

a spring garden calculator

crop
name
weeks indoors
before transplant
transplant (or sow) date,
relative to final frost
sow indoors
from-to
transplant
(or sow)
vegetables
arugula direct sow only 4 weeks before
beans (bush or pole) direct sow only at frost date
beets* 5 to 6 2 weeks before
broccoli 4 to 6 2 weeks before
cabbage 4 to 6 2 to 4 weeks before
carrot direct sow only 2 to 3 weeks before
cauliflower 4 to 6 2 weeks before
chard* 4 2 weeks before
celery, celeriac 10 to 12 1 week after
corn* 2 to 4 0 to 2 weeks after
cucumber* 3 to 4 1 to 2 weeks after
eggplant 6 to 8 2 weeks after
kale*, collards* 4 to 6 2 to 4 weeks before
kohlrabi* 4 to 6 2 to 4 weeks before
leeks 8 to 10 2 weeks before
lettuce* 4 2 to 4 weeks before
melons (muskmelons)* 3 to 4 1 to 2 weeks after
melons (watermelons)* 3 to 4 1 to 2 weeks after
mustard* 4 2 to 4 weeks before
onions 8 to 10 3 to 4 weeks before
pak choi 4 2 weeks before
parsnip direct sow only 3 to 4 weeks before
peas direct sow only 6 weeks before
peppers 6 to 8 1 to 2 weeks after
radish direct sow only 3 to 4 weeks before
spinach direct sow only 4 to 6 weeks before
squash (summer)* 3 to 4 1 to 2 weeks after
squash (winter)* 3 to 4 1 to 2 weeks after
tomatoes 6 to 8 1 to 2 weeks after
turnip direct sow only 2 to 3 weeks before
herbs
basil* 4 to 6 1 week after
cilantro direct sow only 0 to 3 weeks before
dill direct sow only 0 to 3 weeks before
parsley 8 to 10 2 weeks before
annual flowers
calendula* 6 1 week before
cosmos* 6 at frost date
hyacinth bean* 4 to 6 0 to 1 weeks after
impatiens 8 to 10 1 week after
marigold* 6 1 week after
morning glory, moonflower 4 2 weeks after
sunflower* 3 to 4 at frost date
sweet peas 4 to 6 1 to 2 weeks before
viola, pansies 8 to 10 2 weeks before
zinnia* 4 1 week after
*Chard, collards, kale, kohlrabi, lettuce, mustard, plus many familiar herbs and annual flowers, are probably easiest direct-sown. In short-season Northern areas, starting heat-loving melons, cucumbers, and squash indoors (though all easy to direct sow) may offer a headstart.

how to plant, harvest and store vegetables

Margaret's seed-starting calculator