Small Onions…why? And what to do about it

I planted some onions this year from onion sets that I purchased locally. They are Yellow Sweet Spanish Onions which I understood from the lady who sold them to me, to be large and good for storing. However, mine are falling over and one has even produced a flower, telling me they are near ready to harvest, but the builds are smaller than I hoper for with most of them being around the size of a golf ball.

What did I do wrong? I planted the onion starts 10 cm apart, they do not have to compete for space, sun or water, so I think it must be something to do with the soil nutrients.

So I did a little research. It turns out that the fertilizer I’ve been using in the garden which is good for fruiting plants like peppers and tomatoes is high in nitrogen. This is good for the onions while they are growing their greenery, but once they are looking strong up top, I should have changed it up.

I have a second set of onions that went in late, and I’m giving them bone meal so that they have more calcium and phosphorus. I’ve learned that this should lead to bigger bulbs, where as the high nitrogen fertilizer I have been using on pretty much all my plants stimulates the up top green growth and flowers.

I’ve also looked at companion planting options for next year, when I’ll be able to plan my garden differently because I won’t be held hostage by a bed building schedule, like I was this year.

It seems that Onions like to be planted along side tomatoes and peppers. This works because the onions roots are shallow, and while tomatoes and peppers do have some shallow roots they predominantly go deeper into the soil, so they will not interfere with the onion bulbs. The other benefit to the Peppers and Tomatoes is that the Onions produce an odour that deters the pests that attack them, so its a win win scenario. For more info on companion planting, see my post on Companion Planting for Vegetable Gardens

I’m incredibly grateful for the freedom to be able to grow my own food and the space to do so. I respectfully acknowledge that I live and work on the Tla’amin Nation territories. I am also grateful to God for bringing me to this beautiful place and blessing me with the abundance of this garden.