How to Sow Seeds Indoors

Dreaming of a beautiful, bountiful spring garden? Whether you’re replenishing last year’s crops or adding new varieties, now is the time to start your seeds! Sowing your seeds indoors gives you an early jump on the growing season: you can start growing frost-sensitive plants in containers indoors, then transplant them outside once the weather warms up. Right now, you can sow beets, onions, spinach, peas and radishes to harvest in the spring. Here’s everything you need to know.

 

1. Fill your containers up to 1/2 inch from the rims with lightly but evenly moistened planting mix, and press it gently so it’s firm and level. Take care not to overly compact it. Next, use a pencil to press holes into the planting mix to the right depth for your seeds (see your seed packets for specific details, but a good rule of thumb is to cover seeds to a depth of four times their diameter). Then, add one or two seeds, spaced an inch apart, to each small container and cover with additional planting mix. Label each container with the plant’s name and the sowing date, and water the planting mix.

 

2. You can place the containers inside a large plastic bag, cover with plastic wrap, or place them underneath a greenhouse cover. Set the containers in a warm, draft-free place until the seeds germinate; the top of a refrigerator is a good place, as the seeds don’t need a light source until they sprout. If your containers are well insulated you probably won’t need to water them until after they sprout and you move them to a sunny area to continue growing.

 

3. Time between planting and sprouting varies, but it’s usually between 7 and 14 days. When you see sprouts coming out the top of the soil, remove the plastic and move the containers to a sturdy ledge or table next to a sunny, draft-free window, or to an area where you’ve set up growing lights. The containers should be as close to your light source as possible so the seedlings don’t have to “reach” for the light, which results in leggy, weak plants.

 

4. Check on your seedlings daily to make sure the soil is moist but not wet. Use room-temperature water and a gentle delivery system, such as a mister, so you don’t disturb the fragile seedlings. Rotate them from time to time to make sure the light is reaching them evenly. When the immature plants are well established in their containers, you’re ready to transplant them into your garden!

 

Looking for more tips? Read our Q&A with seed expert Matthew Hoffman, of The Living Seed Company, for answers to common questions.