If you love onions, and want to try growing them this year, now is the time to get started! If you want large, fully-developed onions, you should sow the seeds indoors now.
Unlike many vegetables started from seeds, onions don’t need to be started in individual 4 or 6-pack planting cells. They can be started in plastic fruit containers, such as strawberry containers.
Fill the container with fresh, premoistened seed starting mix. Lightly sprinkle your onion seeds over the mix and cover with a little more soil. Close the lid to keep the humidity high until the seeds sprout. After they sprout, remove the lid and place the containers in a sunny window or under lights and watch them grow.
When the green tops are 3-4 inches high, cut them back a little, so they don’t flop over and the plant will dedicate more energy to growing the onion bulb, instead of the tops.
Make sure to keep the soil evenly moist. One trick to watering your seedlings is to pour the water into the bottom of the seed tray.
The soil will soak up the water and your seeds won’t be washed around. Check your trays a few hours after they have been watered to make sure the soil is evenly moist and there is no standing water left in the tray. If the soil hasn’t absorbed all of the water, drain the tray, so your seedlings don’t drown or rot.
Onions are pretty hardy, so your seedlings can be planted outside in early spring. Before you stick them directly in the ground, they must be hardened off for a week or two. Place your containers outside for a few hours each day.
Gradually increase the time outside, and soon your seedlings will be acclimated to the outdoors. When they are ready to plant in the ground, gently dump them out of the container and plant them in rows. If some of the roots have become tangled, gently tease them apart to separate the individual plants.
Growing your own onions doesn’t require a lot of special equipment. It also allows you to try varieties that you might not find in the grocery store, so get started today!