Seed Starting Calendar 2027

Count back from the median last spring frost for your area. Each crop has its own lead time: UNH Extension gives onions 8 to 10 weeks from seed to transplant, peppers and eggplant 8 to 10, tomatoes 6 to 8, and cucumbers and squash 3 to 4. At Columbus, Ohio (median last frost April 18), tomato seeds go in Feb 28 to Mar 14 for spring 2027.

NOAA computes it for each weather station from 1991 to 2020 records as a probability. The median is the date after which a 32°F night still comes in half of years. The 10 percent date is later: by then the last freeze has passed in 9 of 10 years. Tender crops such as tomatoes, peppers and basil go out after the later date.

Six to eight weeks before they go outside, and UNH Extension sets them out 1 to 2 weeks after the last frost. That puts sowing about 4 to 7 weeks before the median last frost: late February in the Deep South, March across most of the country, and April in the northern Plains and mountains.

Celery (10 to 12 weeks), parsley (9 to 10), and onions, leeks, peppers and eggplant (8 to 10 weeks). Onions and leeks go out about 4 weeks before the last frost, so they are the first sowing of the year in most gardens.

Peas, radishes, carrots and beets go in 2 to 4 weeks before the last frost; beans and sweet corn around the last frost date, once the soil warms. University of Minnesota Extension recommends fiber pots for crops that transplant poorly, such as cucumbers and squash, when they are started indoors.

University of Minnesota Extension: "Keep lights no more than 4 inches above the tops of your seedlings: as close as 2 inches is ideal." Seedlings need 12 to 16 hours of light a day, and a south-facing window can carry a few plants.

Mostly not. UF/IFAS plants Florida by region and month, the University of Hawaii by elevation, and University of Arizona Maricopa County Extension by month for the low desert. Their state pages lead with those months.