• How do you start and grow onions?

I found that onion variety is really sensitive based on the area of the country you are in. For us I found Wala Wala does really well. That being said, it also depends on…I’m not sure…luck maybe?

I’ve had great luck planting onion “sets” as long as I hill them and then expose the bulb at the right time. Several years ago I did a direct planting of seeds in one of my raised beds and it worked just fine, huge crop. The next year not a single seed sprouted. I have no idea what went sideways.

This year I am trying to do my own onion sets, we’ll see how that goes. For potting soil in my “mix” I use a regular store bought potting soil such as Miracle-Gro, Sta-Green is fine as well. But I try to mimic the soil they will grow in. So here is the mix (approximately):

• 3 parts potting soil
• 1 part coarse sand
• healthy dash of vermiculite

Yesterday’s mix was; 4.5 cups of potting soil, 1.5 cups of coarse sand, 1/3 cup of vermiculite. The mix doesn’t have to be exact.

I dampen the potting mix just shy of squeezing water out. Then I fill each container, I use deeper pots…about 4”, to about 1” from the top with the mix. I hold back enough mix to cover each pot with ¼” – ½” of the mix. I spread the seeds out randomly in each pot…maybe 30 – 40 seeds per 3” – 4” diameter pot. Then put 1/4” – 1/3” the mix over the seeds and water in just enough to settle the soil. As an option: you can cover them with 1/8” – 1/4” of Vermiculite.

When the tops are about 8” or so, if they get that far before I transplant them, I trim them back to about 5” – 6” to stimulate root growth vs stem growth.

I start my sets about 3 months prior to last frost. I keep them kinda damp but not saturated. You get a big clump of sets if all went well. I separate them and give them a couple days to dry before planting. Then store them in a cool dry place until ready to plant. But, I try to go straight from the seedling container to the raised bed after a day or two to dry. Onion sets can handle a light frost, like maybe down to 26degress or so. So I don’t wait until after the last frost to plant them, I just make sure that the ground isn’t frozen (duh) and no real frost for a week or so (gives the roots time to get settled in). If a hard frost is predicted I just cover them up for the night.

Some folks trim the roots back to 1” before planting, not me. I do look for weak or rotted roots, those I trim back.

All my raised beds drain well; that is the best soil for onions. Heavy soil or soil that becomes saturated with water is not good for onions. When I plant I make sure the little set bulb is covered but not buried deep. I mound the new plant to help stabilize the plant for a couple of weeks, then I let the bulb emerge and stay exposed.

Last thought…onions need consistent deep watering; but don’t over water, soil needs to drain so roots aren’t sitting in saturated soil. And onions need fertilizing. To start use a 1-2-1 ratio fertilizer (such as a 10-20-10 or 5-10-5). You can add bone meal to a 10-10-10 fertilizer to get the heavier phosphorus content. After about 3 weeks or so go straight (or almost straight) nitrogen every 2 – 3 weeks. You can go with as high as a 20-0-0 fertilizer if you want…just follow directions. Blood meal is a high nitrogen-only source. I do use a furrow between my rows and put the fertilizer in the furrow. The roots will absorb the fertilizer so make sure the soil is damp before you fertilize, and then water in the fertilizer really well to avoid “burning” your plants. Organic fertilizers are great…but normally take much, much longer to break down so act accordingly. Osmocote isn’t organic but won’t burn.

Note #1: I like Pennington Alaska fish-based fertilizers < https://www.pennington.com/all-products/fertilizer/alaska >

Note #2: If you aren’t afraid of non-organic fertilizer I think Osmocote is pretty dang good (probably the best for gardens) < https://amzn.to/4rHbJUX >

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