Thursday, August 30, 2018

An Onion Experiment - The Reveal

This past spring, I decided to do a little experiment with onions.  I had read in a local seed catalogue that onions sown in April would grow larger than those seeded in February, which is when they are traditionally sown around here.  I was intrigued by this statement and quite skeptical, to say the least, so I decided to put it to the test.

I chose to use Copra's in my experiment as I have grown them for several years and normally seed a larger quantity of them compared to other varieties since they store incredibly well.

Copra Onions (2014)

To test out the timing, I sowed one third of the Copras on February 8, one third on March 9 and one third on April 4.  The remaining varieties - this year I grew Rossa di Milano, Wethersfield Red, Jaune Paille des Vertus, Ailsa Craig, Patterson & Red Wing - were all sown in March.  Yes - I'm sort of an onion junkie.  I keep adding new varieties but can't seem to get rid of those that I've already tried 🙄.

Fast forward to April 30.  Imagine my surprise when I transplanted the onions and realized that the April sown Copras didn't look all that different from the February sown ones.

Arrows point to the rows containing the February vs April sowings

I don't have a photo but I made a note that the April seedlings actually looked BETTER than the March sown seedlings.  Just as a side note if you've never grown onions from seed, the seedlings do tend to look rather pathetic when you transplant them, but they quickly recover - it's nothing to worry about.

Three weeks later:  Had the rows not been labeled, I would have been hard pressed to tell you which was recently seeded and which was seeded months ago.  In the photo below, the April seeding is to the left of the red line, the February is on the right.

Left:  April sowing
Right:  February sowing

Ok, so the seedlings looked pretty much the same, but a lot can happen after a few months in the ground.  The proof is in the pudding...or in this case, the bulbing up.  Only time would tell.

Here we are, at the end of August, and time is up.  So what did I find??  Drum roll please.....

From left to right:  February, March, April sowings

The onions in the photo above are the largest specimens from each sowing, starting with February on the left, March in the middle and April on the right.  I was shocked.  As in "my mouth is open and I'm not understanding what I'm seeing" shocked 😮.

Here is February and April, side by side:

Left - April; Right - February

I'll discuss other factors that (positively) affected the onion harvest this year in a future post.  Suffice it to say, however, that after a few years of disappointing harvests, I'm thrilled that this years bulbs are more than respectable when it comes to size.

Copra bulb seeded in February

Below are photos of the total Copra harvest from each sowing.  The March harvest was slightly larger as I ended up subbing some Copras when I was short on seedlings from the other varieties.  Standard sized hand pruners provide some perspective:

February Seeding

March Seeding

April Seeding

In terms of overall size, both the April & February sowings produced a greater number of large bulbs while most of the bulbs in the March sowing were on the smaller side.  This seemed rather odd - that the middle sowing would be the smallest.  Then I remembered something:  I used cell packs in February & April vs. a plug sheet in March.  I often have an issue with plugs as they tend to dry out easily and it's hard to tell if they need water or not.  Remember how I said that the April transplants looked better than the March ones?  This may be the reason which then translated into smaller bulbs.

Setting aside the March sowing, when I'm comparing the February and April sowings, everything (including the containers I sowed them in) was the same so it's truly an apples to apples comparison.

Bottom Line:  The average bulb size looks more or less the same for the February and April sowings.  Is my mouth dropping open again?  Why yes, it is 😉

I'm going to reserve final judgment until after the onions are cured and weighed but I have to say that I'm more than a little optimistic that I'll be sowing my onions in April from now on (and using cell packs, not plug sheets!).  What a difference this will make, both in freeing up space under the grow lights in February & March and eliminating a full 2 months of coddling onion seedlings.  My, my...this is all rather exciting!

“Enjoy the little things, for one day you may look back and realize they were the big things” ~~ Robert Brault


  1. They do say that later sowings catch up and it certainly looks to be the case here. You've got a great onion harvest this year, well done.

    1. Thanks Jo. I knew early sowings of things like peas were not worthwhile but every source or book that I read indicated they needed a super early sowing - except for that one seed catalogue. Goes to show it pays to try things out, even when they seem unlikely to succeed.

  2. As, Jo commented often later showings catch up as they don’t have an initial set back. We used to grow our sets on early in modules in the greenhouse and then found that there was no difference between the onions started this way and those planted straight in the ground.

    1. I remember when you did that experiment. You really never know until you try - When it comes to trying new things in the garden, I always feel that one success makes up for a dozen flops.

  3. What an interesting and useful experiment, Margaret. I don't grow onions from seed, but maybe I'll try. Starting them in April is a more civilized month for me to be coddling seedlings. P. x

    1. It really will be so much easier to care for the seedlings over 1 month instead of 3! It also cuts down on the amount of time in which things can go wrong :)

  4. That is an exciting development - and one that should indeed help in your overall indoor seed starting activities. I've had such dismal luck with onions that yours look truly amazing to me! I do understand the compulsion to grow so many different kinds. I'm that way with garlic, and peppers, and tomatoes, on.

    1. I know - it's so hard to cut down on varieties! I often say that I don't mind at all when a particular variety does badly as then I don't struggle with the decision of whether or not to get rid of it!

  5. Experimentation is at the heart of gardening. Congratulations on your excellent harvest!

    1. Thanks Jason - it's one of my favourite things to do!

  6. That's really interesting. I always sow in February, which is inconvenient because we like to go away at that time. I'm going to try April next year. Thanks!

    1. We are more or less in the same latitude so I would think our results would be similar. I would do a half in Feb./half in April seeding though, just in case!


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