Growing Storage Onions Part 4: Interviews with Experienced Gardeners

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credit Terry Phillips

By Terry Phillips.

Editor’s Note: In 2020 Terry did a three-part series on Growing Storage Onions:

She also wrote a fourth post which we saved for the right occasion.  As it’s February again and time to start planting onions from seed indoors, we thought now was the perfect time to publish this post.

Here are some fascinating interviews Terry did during the winter of 2020 with 3 experienced onion growers.  Lots of wisdom in the words that follow:

First; Bay Phillips says:

“I’ve never had much success with sets, or seeds, so last year I did quite a lot of research before I planted.

I came across a few articles on ‘winter planting’ in milk jugs outside, so thought that I’d give it a whirl. I cut 4l sized milk jugs in half, cutting three sides but leaving the fourth side intact as a hinge. I punched holes in the bottom, filled up the jug with sterile organic potting soil (I made my own, lots more work…this year I’ve bought the pre-mix bag), and planted about 16 seeds per milk jug. Taped it up, left the lid off, and put them outside: date Feb 24. I wanted about 150 onions so had 10 milk jugs. (I also planted leeks and spring onions the same way.)

The milk jug collection on the deck grew, and started to send Nigel a bit crazy! The milk jugs were mini-greenhouses, but I didn’t have to contend with slugs or mice.  But the seedlings had to contend with fluctuating temps and became quite sturdy. I hardly had to ever water them as enough rain dropped through the top to keep them moist. 6 jugs fit nicely on a rubberneck tote lid, which also kept them from drying out.

When they started growing, I fertilized them once a week with fish fertilizer. When they started poking out of the container, I cut them back to about 3 -4 inches. When the days got warmer, I opened the container to expose the seedlings to direct sunlight.

I had read that the seedlings should be at least 10 weeks old before transplanting out in the garden, so I didn’t put them out until the first week in May. They went into a bed that I had put seaweed on the previous winter. I worked into the top 4 inches a fertilizer mix very similar to yours [Terry’s], but I had no compost left as I’d used that on the carrot and parsnip beds. I think every seed grew, and each transplant came out of the jug with lots of soil around the roots.

I waited a few weeks until the transplants took hold and then mulched the beds. I decided that my scrunched-up leaf mulch might be too thick to use for this so I used quite a thick layer of alfalfa pellets which seemed to work very well. After that, I did nothing until harvest, except try to keep up with watering and pull the occasional weed that managed to find a spot to grow.

I grew two varieties, a yellow hybrid called Patterson, and a red-tinged variety called Blush. The Patterson variety was more successful, partly because the necks were much thinner and so better for drying, and they produced bigger onions. The ones on the edges of my raised beds didn’t grow as well.

I was very careful with drying them…I used the method that you used for drying your garlic. I wove the tops through the lattice around the inside of the carport, where there was plenty of breeze, but they were out of the direct sunlight. (As they began to dry some of them fell down and I wove them back in again, or just left them on the bench in the carport.) I left them there for at least a month.

When I was sure that they were really dry I braided the big ones up and put them in the porch. It stays above freezing but isn’t super dry, and not dark at all.  As yet none of those have gone mouldy, and it’s still cold enough in the porch that they haven’t started sprouting. The small ones I put in a cardboard box and left in a cold closet.  One of those went mouldy.

I have enough onions left to last me through February. When I cut them open they are still really plump, spraying onion juice everywhere.

I planted Walla Walla onions in milk jugs on my deck on July 1st. I transplanted the seedlings into the garden on Aug 18. I neglected them for a while, then had to pull weeds several weeks later.  At that time I top dressed them with my fertilizer mix, then mulched them with maple leaf mulch.

I planted about 50 seedlings and it looks as if only half of them survived the last winter episode of -10C or so. The tops are bent on the ones that survived, but green and look as if they might produce something. I had hopes that my storage onions would last until I could get some of these to maturity but it’s not to be. I’ll be a couple of months short, and the Walla Walla may not make it anyway.  Time will tell. I will substitute leeks for onions.

I do think that last summer’s weather was good for onions and that it contributed to my success.

The main negative to the milk jug method is that the coating of sticky stuff on the tape that seals the cut hardens and disintegrates over time, leaving little pieces of plastic everywhere. I washed and bleached last year’s jugs and am using them again this year. I am experimenting with different tape types, this time just using a minuscule piece on each cut side, and just closing the cut in the jug, but not completely sealing it. Most of Nigel’s enthusiasm for building a greenhouse is that it will remove the ‘juggery’ from the deck!”

Next we have tips from one of our Garden Club members:

“I have grown onions for many years in the interior of BC. My soil was rich in humous and the garden had full sun. I used tilled up raised beds. I always put in bone meal and compost for fertilizer. I mulched with a thick layer of grass clippings. I always was amazed when I pulled the onions that they had earthworms living right in amongst their roots, I am sure that the worms benefited them both with their castings and by creating good drainage under the bulbs as well.

I used both using seeds and sets. From seeds, I grew the large Chelsea sweet onions, starting them in November to maximize the size of the onion at harvest. (Having read that onions are sensitive to the length of daylight hours and must be started before the shortest day.)

I grew the seedlings where they had a lot of natural light but in cool temperatures. I started the seedlings in small trench-like plastic trays, and then moved them to 4” pots.

For winter storage I planted yellow Stuttgarters ordered from William Dam seeds. I planted as early as possible in April as soon as the ground could be worked, often in a snowstorm! For years I had total success with this variety. When it came close to harvest time I would bend the tops down to encourage them to dry off. I continued the drying off after pulling them by leaving them up on crates under cover but with good air circulation. Once the stems had softened up I would braid the ones that had small flexible stems (any onions with thick stems I used immediately as they do not keep well) by braiding in a length of heavy twine the full 8-foot length.  I added strength so it would not break. I tied a loop in this twine and could then hang it in a cool dry place for winter use. It was a very convenient way to store them and prevented spoilage.

I had total success with keeping these onions for over 30 years. Then one year I used inferior sets purchased from the hardware store and unfortunately, they carried some type of disease that caused rot in the stem end, and although all the steps had been carefully followed, I lost them all. This introduced disease to my garden soil and it continued to cause problems for me every year after.”

And our third gardener, Theresa O’Brien from Q Gardens, kindly offered these tips in an interview:

  • Some of the onions Theresa grows are Copra, Patterson, Bianca di Maggio, Red Wing, and Mars. Shallots are easy and they mature earlier in our climate.
  • She seeds between the last week of Feb and the 1st week of March with bottom heat. She uses 4” pots and 15-20 seeds per pot.
  • The mix is her own potting mix of compost, rotted leaves, garden soil, and sand, with a small amount of organic fertilizer in the bottom half of the pot. The top half of the pot gets the same without the fertilizer. Seedlings are ready to plant in 6-8 weeks. Theresa doesn’t trim her onion tops.
  • Before planting is the time to amend your soil. One of Theresa’s greatest tips was not to scrimp on organic fertilizer at planting time. Mix it into the soil now, and down where the roots can get it. Onions need to grow fast while it is still cool and they won’t catch up if starved at this stage. She doesn’t need to side-dress with this method.
  • While planting don’t overcrowd. Wet the clump, tease apart, and plant 2-4 in a hole. The more you plant in a clump, the further you should space your planting holes.
  • Mulch is good; Theresa has used a living mulch with her onions. In mid to late May she overseeds with white clover. The onions have had a chance to get established and the clover doesn’t take over until the onions are nearly done. Clover is a nitrogen fixer and suppresses weeds. The clover is turned in before it flowers and after the onions have come out.
  • Onion plants won’t get much bigger past the end of June or early July. Then they set their bulb. This is because of the day-length situation of onions [see part one for a description of day-length]. When the tops are over and soft, the bulbs are pulled and left on the ground in the sun. The onion tops are flopped over the bulbs.
  • Storing is done in a cold, dry, and unheated outbuilding where it won’t get to freezing.

Diseases:

  • The worst disease Theresa has come across in onions is downy mildew. In a certain light, the plants look like they are covered with a dark purplish-black velvety coating. It can decimate your crop. Prevention is the best cure. Avoid overhead watering and water early in the day so plants have a chance to dry off.
  • Other diseases are botrytis and onion thrips. But not so much of a problem.
  • To prevent diseases and pests in your onions move your crop every year.

Thank you to all three of you for your contributions to onion growing on Quadra Island!

Terry Phillips is a gardener on Quadra Island who has long strived to grow great onions.

  1. Valerie Barr

    Thanks Terry for this inspiring collection of methods. I hope to start my onions and leeks this week. Val

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