How to grow healthier onions! Part 2

How to grow healthier onions! Part 2

Last week in Part 1 we talked about growing onions from seed. We left off with our onions growing under lights or in a greenhouse. Let's pick up the discussion! Now its…


As your seedlings grow and get taller, many tout the benefits of giving your seedling as ‘haircut’ as they grow.  There are pluses and minuses to this strategy.  On the plus side, the seedlings will be easier to handle and transplant. You won’t have to deal with the longer leaves, which can become tangled or get kinked as you handle them. Also, less leaf area puts less pressure on the roots after transplant, during the re-establishment process.  Finally, it helps develop thicker stems. However, the negative tradeoffs are the seedlings have to expend energy to heal the cuts, which are also susceptible to infection.

We have never used this method, despite its popularity in some circles. If you do decide to go with the ‘haircut’ wait until your seedling are at least 5-6 inches tall or begin to lop over. Use a clean, small, sharp pair of scissors to trim the leaves to about 2-3 inches tall. As a bonus, you can eat the trimmings as you would green onions!



We transplant our onions about the first week of May; give or take depending on weather. Onions are hardy, so a light to moderate freeze is not a concern.

Allow the soil to warm and gather the heat of the sun by pulling any mulch or trash aside.  If your soil is too wet, use a fork to lift the ground and aerate, allowing it to dry out for a day or two. If your soil is drier, wait until you are ready to transplant before preparing the transplant bed.

Onions do best in soil that is moderately high in organic matter, fertile, loose and well drained, with no standing water after a rain. To ensure healthy bulbs, rotate with other crops in a 3 to 4 year rotation. If fertility and organic matter is low apply some compost and work it in. Create a nice loose seedbed free of dirt lumps and rocks.

We transplant late in the day, usually after 5 pm, avoiding the heat of the day to reduce transplant shock. This allows plants to recover overnight.

Plug method

On the day you plan to transplant, pay attention to any watering you do. Your seedlings should be moist but not wet. It is difficult to handle wet plugs. You want the plugs moist enough for the soil to hang together and not fall away but not so wet that its muddy.

When the seedbed is ready, carefully remove the plug from the tray. Place it so the top of the plug is about level with the soil surface but not sticking out. If your soil falls away from the plug as you are removing it from the tray, just use the planting instructions for bare-root transplants below.

Carton method

If you used the milk carton method, on the day of transplant only water sparingly early in the day, as needed. The soil should be moist but loose enough to easily fall away from your transplants. This will allow you to easily separate the seedlings and plant bare-root style.

When you are ready to plant undo the carton spout and open up the end, flattening it so the sides are splayed out.  Scoop your hand underneath the soil, wiggle your fingers to cause some separation, and gently separate a small section, removing it from the carton. Handle the plants at the strongest part of the stem, right above the tiny bulb; do not squeeze the stems or crush the roots. Gently tug and loosen the soil to separate the roots of individual plants. As you work to separate the plants in your hand, wiggle your fingers to cause the soil to shake out and fall away. Some tearing of the roots will likely occur. Keep it to a minimum, of course, but don’t stress.

Lay out about a dozen seedlings at a time and then transplant. This will minimize the roots’ exposure to light. Or work with a partner to separate and transplant as you go. Insert your index and middle finger into the soil, creating a hole as you pull towards you, while inserting the plant directly behind your fingers. Pull your fingers up and out, release the soil to fall back in around the plant. Very lightly settle the soil using four fingers in all four corners around the transplant.

Make sure to displace the soil deep enough to be able to accommodate the roots. The tiny bulb of the onion plant should be just below the surface with the growing point/new leaf enough above the surface, so it will not get buried when you water them in or during a heavy rain.

Onion seedlings do not have much of an enlargement at the base of the stem. Look for the point where they change from the white to green. Place the base of the seedling just deep enough so that no white is showing. Make sure the roots are all in the ground and covered. Don’t worry too much about being exacting; you will get better at it as you go.


We transplant the seedlings about 4 inches apart in a double row with 6-8 inches between rows. Water the seedlings in immediately after planting to thoroughly settle the soil around the roots. Do not worry if the seedlings lay on the ground and look limp as you are planting. They will revive. If it is cloudy and cool, you should not have to water them again.  If it is sunny and warm, water them the next morning before the heat of the day.

Dakota Tears is a long-day onion, which are best grown in the North where the summer daylight period is longer. These onions require at least 14 hours of light to bulb up. The plant grows leaves in spring and early summer; each leaf corresponds to another layer in the onion bulb. Once the days begin to shorten, the onions will begin to form bulbs.

As the season progresses, we will provide growing, harvest, and storage tips! Until then… Here's to the best onion crop ever!

Our best to you,

Theresa & Dan

For more on transplanting onions and to access our companion video, click here!