Planting Red Onions in Early Spring in NJ, Zone 6

Yesterday, my husband pulled a living onion out of the ground in our backyard. It’s March 13, and our NJ raised bed garden is, for the most part, just piles of dormant earth waiting to wake up. So, this was very exciting for us.

He diced it up immediately, and we sprinkled the tangy, fresh, deep-purple-and-white-streaked bits of goodness over our bowls of chili that night. I used the rest, along with some carrots and kale, to flavor a vat of chicken soup.

Last year, I had put a few red onion bulbs in the ground “for fun,” not yet realizing that I was soon to season my food with the most delicious, organically grown onions I’ve ever tasted in my life. We were so enamored with our mini experimental onion crop, that we thought we’d share what we’ve learned about how to plant onions.

Keep in mind that this information is just a starting point. You may find it helpful if you’ve never grown onions before and just want to get started with a small crop of them to see how things pan out.

Where to plant onions:

Onions are pretty ideal if you don’t have a lot of space in your yard. Position yours behind the lower-growing crops like lettuce, but in front of the taller crops, like tomatoes.

When to plant onions: 2 to 4 weeks before the last frost is expected. In our part of NJ, the last frost usually happens before May 15.

  1. Clear out a row in your garden for the onions. Loosen the soil to about six inches deep so that the onions have room to grow. Add a couple of inches of composted soil, to ensure a rich, fertile area, and mix in well.
  2. Dig a 6-inch-deep trench in the row, and pile the dug-out soil along the side (so you can fill it back in later). You may want to use a string as a marker, to ensure that the row is straight.
  3. Plant the onions. Open your bag of red onion bulbs. Some will be larger and some, smaller. Place one onion bulb in the trench every 2 inches or so. Cover with soil, pat down and water until the soil is just moist.
  4. Thin your beds. When the weather routinely gives us 75-degree days, it will be time to thin the onion bed. At this time, the onion sprouts will be “spring onions” or scallions, reaching for the sun, fighting each other for space. (You can even dig out a few and eat them if you use these in cooking.)
  5. Separate. Do not be afraid to dig into the onion bed and separate your little onion children so they have room to grow. Dig around the plants and loosen the soil, taking care not to damage the growing onion bulbs. Gently lift a clump of onions out of the soil and use your fingers to jiggle them about they separate from one another. Place each, individual onion plant in a pile on the side.
  6. Replant. Re-plant each onion shoot (or scallion), with about 2 inches of space in between each one. You can use a tape measure if you want, but you really don’t have to. Instead, just imagine a fully mature onion growing beneath the ground, and estimate how much space it would need to form properly. This is generally how I plant my garden vegetables, and it works for me.

Fertilizing your onion crop: I have read articles recommending to fertilize the onions 3 weeks after active growth has begun. Most people hear the word fertilizer, and they think of Miracle-Gro and other chemical-based fertilizers. This is not what we mean. In our organic garden, we augment the soil with organic compost several times throughout the gardening season. This produces lush, hearty vegetables.

When to pick scallions: when the green shoots are about six inches tall.

When to harvest mature onions: when the leaves turn brown and fall over.

Of course, you can pick an onion at any time during the growing season just to see how it’s doing, and how a “young” onion tastes. I used a few last year that were half-ready, and found them to be delicious in an omelet, lightly fried with potatoes, and sprinkled over our salads.

This is my own method of growing red onions in my little NJ garden. You may find your own method that works for you. Good luck, and happy onion planting!