While starting onion seeds indoors is recommended, it is also recommended to sow onion sets outdoors. In order to encourage a large bulb, you want to transplant them in the spring. One year I tried planting the bulbs in the fall just like garlic and they did pretty well because we had a mild winter. I felt a little empowered and planted them the next fall and we had tons of snow which they didn’t like. My suggestion is to grow them in the spring!
Indoor Sowing Tips:
Sow onion seeds in mid to late winter indoors under T5 grow lights.
Onion seeds like temperatures between 60 and 70°F in order to germinate.
Sow a bunch of onion seeds 1/4 inch deep together in a 4- inch pot.
If the green stem gets taller than 4 inches, then give them a trim.
If needed, loosen the soil before transplanting. I do this for any root or bulb veggie.
Don’t forget to harden off the seedlings before transplanting.
Carefully separate the seedlings and transplant them in mid spring. Since onion roots are very hardy, they can withstand a little tug.
Plant onion seedlings 4 inches apart or 9 per square feet.
Sprinkle some bone meal or used coffee grounds to add phosphorus and calcium which is good for bulb and root vegetables.
Also, don’t forget to water them during the day until the drip system gets turned on.
In the spring, be ready for temperature swings by using a hoop tunnel and some garden fabric.
Outdoor Sowing Tips:
Keep the onion sets in a cool and dark spot until you are ready to sow.
Sow each onion set outdoors with the pointy side up and the roots down in early to mid-spring.
The top of the onion set should be right below the soil line.
Plant onion seedlings 4 inches apart or 9 per square feet.
Sprinkle some bone meal or used coffee grounds to add phosphorus and calcium which is good for bulb and root vegetables.
Also, don’t forget to water them during the day until the drip system gets turned on.
Protect the area with a hoop and some netting. While the squirrels have never eaten my onion sets, they have been known to dig up the bulbs before they start sprouting.
In the spring, be ready for temperature swings by using a hoop tunnel and some garden fabric.
Growing Tips:
In the summer, provide consistent moisture with a drip system.
If onions need any plant food, give them used coffee grounds, bone meal or balanced plant food.
Onions don’t like weeds so remove them!
