Time to plant seeds indoors for cool weather vegetables

broccoli in Parkside garden in Buffalo NY
Photo by Connie Oswald Stofko

by Connie Oswald Stofko

You can plant seeds indoors now for cool-weather vegetables such as broccoli, Brussels sprouts, cauliflower and cabbage, said Julie Emerling, a grower at Lockwood’s Greenhouses, 4484 Clark St., Hamburg.

Cool-weather crops are ones that you’re going to plant outside around mid-April, depending on the weather.

(Tender crops such as tomatoes and peppers are planted outside after the danger of frost has passed, which is usually Memorial Day or the end of May. It’s too soon to plant those seeds indoors; the seedlings will get leggy and unhealthy. You generally start seeds six to eight weeks before it’s time to transplant them outside, so you would start tender crops inside around the beginning or middle of April.)

For your cool-weather crops, plant them inside now and keep your trays warm until the seeds have germinated, Emerling said.

When the seedlings poke out their second set leaves, try to expose them to temperatures that are a little cooler, in the 40s or 50s Fahrenheit. If we get a day like we had Sunday, with warm temperatures and sun, put your trays outside for a little bit in afternoon, she said, but don’t leave them out too long. Keep doing this to acclimate your seedlings to the outside.

Whether you can plant the seedlings in the ground in mid-April depends on the weather.

First, the soil can’t be frozen. It can be cool, but not frozen.

Second, the soil has to be dry enough that you can work it. Scoop up some soil and squeeze it in your hand. If it forms a glob, it’s too wet and you can’t work it. If it’s crumbly, you can work it.

Third, the temperatures should be consistently above freezing at night. (For tender crops such as tomatoes, you want nighttime temperatures to be around 50 degrees Fahrenheit, but for cool-weather crops, simply above freezing is fine.) If we get a night where temperatures are predicted to dip below freezing, cover the plants with a cloth, like you would do in the fall to protect from a frost.

Lettuces like cooler temperatures, but they definitely can’t tolerate a frost, Emerling said. Sow lettuce seeds directly in a container or a garden bed at the middle or end of April, depending on the weather and soil conditions. You could plant lettuce a little sooner if you plant it in a container and bring the container in if there’s a danger of frost.

If you don’t want to start these vegetables from seed, you’ll be able to buy the plants at Lockwood’s at the appropriate time.

4 Comments on “Time to plant seeds indoors for cool weather vegetables

  1. Yes, now is a great time. To start earlier planting, a cold frame is easy to build too. Inside, plants may require grow lights though.

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