When it comes to gardening, I am a purist and grow plants via seeds. Well, growing onions from seed has been very challenging to me. I just never got past the whisper of a seedling for most of my onion plants. So, this spring I decided to grow onion sets (red, yellow, and white.) How was my first year of onion sets? First, let’s talk about planting first. Then I talk about harvesting in another post.
There are several type of onions: short, intermediate, and long day varieties. See here which onion based upon your climate is the right one for you.
Also, note that sets can bolt; whereas seedlings will not.
Back to the Beginning. Planting.
I planted the onion sets in late April which is later than I should have. Normally, you should plant them 4-6 weeks before your frost date or as soon as you can work the soil. The general rule is four inches apart, 1 inch deep with the pointy side of the bulb up, a foot or more between rows.
Also, when the onions start to push their leaves through the soil, you can easily confuse them to be weeds. Mark them. I used leftover plastic silverware that I kept from prior uses. (Note, leftover chopsticks or straws works great too.)
Use a good organic fertilizer. ( I use Dr. Earth Organic 5 Tomato, Vegetable & Herb Fertilizer
“Mix in a 1-inch layer of mature compost. Make a 4-inch-deep, V-shaped furrow in the prepared bed. Fill the bottom of the furrow with 1 inch of rich compost or a light dusting of dry organic fertilizer, and then water the prepared furrow. Set out seedlings or sets 3 to 6 inches apart, depending on the plants’ mature size.”
My beds contain lots of compost so I didn’t do this step. Be careful of over fertilizing the onions. Organic Gardening says to go easy on the nitrogen fertilizer since you don’t want lush tops in lieu of nice bulbs.
However, I did occasionally sprayed them with Neptune’s Harvest Organic Fish & Seaweed Fertilizer.
By the way, the onions don’t like weed competition. I used ground up leaves for mulch to keep the weeds at bay. (You can store leaves in the Fall.)
Previously, I have used straw as mulch in my beds; however, the straw produces grass. Who needs the extra weeding?
Disease Control
I didn’t have any issues except with animals digging in that bed. (Yes, yet another post. Those darn animals.) However, pests such as thrips and onion maggots as well as smut can damage your crops onions. Organic Gardening suggested to intermingle your onions throughout the garden. It reduces the extensive damage of onion maggots and benefits your other plants too.
“Allium species will ward off pests—such as aphids, Japanese beetles, and carrot flies—from roses, lettuce, carrots, beets, parsnips, and members of the cabbage family.”
I love OG’s suggestion to use some sand at the base to discourage flies from laying eggs. I have more flies than you can imagine.
So, that’s the skinny on planting onions.
Updated: Be sure to read Year 2 of growing onion sets complete with planting video!
Join the Conversation:
- Do you use transplant, sets, or grow your own seedlings? Which one have you had the best luck with?
- What advice can you give about planting onions?
- Did your onions suffer from any diseases? If so, how do you treat the disease?
John O'Neill says
I have gone over completely to Egyptian tree onions. Easy. The “sets” grow on the tips of the flowerstalk. The leaves can be taken sparingly as green onions. The bulbs are like shallots, sweet and tasty. Much more useful than the pyramids!