Growing onions: seeds versus sets

by Adam Pasco

If you grow your own onions then one choice you have is whether to raise your crop from seed or from onion sets.

Close-up of gardener harvesting an onionIf you grow your own onions then one choice you have is whether to raise your crop from seed or from onion sets. Both methods have their pros and cons, so the decision isn't a straightforward one.

In the past I've always opted for onion sets, which are small onions that can be planted straight out on the plot during March or April. The sets slowly swell into large onions, ready to harvest in late summer. Onion sets are convenient, as they don't take up valuable greenhouse space at a time when it's at a premium.

However, this year I decided to grow my onions from seed, and I've just been assessing the results. Yes, I did need to sow them in modular trays in the greenhouse in March, and could have started them even earlier if I'd had a heated propagator large enough to hold everything.

When seedlings had rooted well into their modules I planted them out in rows in May, and they grew really well through summer. They did need regular watering throughout the dry summer we had in the East Midlands, but that would also have been the case with onions grown from sets. The results were superb, and I was surprised at just how large the onions grew from seed.

Perhaps the biggest advantage of seeds over sets is the money that can be saved. Taking the variety 'Red Baron' as an example, I can buy a packet containing 250 seeds for £1.45, or a pack of about 40 heat-treated sets for £3.99. If they all grew then an onion grown from seed costs less than 1p, while one grown from a set costs 10 times that at 10p.

If you're planning to grow your own onions during 2012, then growing from seed will certainly save you money compared to buying sets, seedlings and young plants. I know these are all convenient ways to grow crops, but you'll be paying far more than you need to.

As my mother-in-law always says, “look after the pennies and the pounds will look after themselves”. Look closely at the things you're buying, and work out just much money could you save.

And if you collect your own seed from suitable crops you could be saving even more, but let's leave that subject for another time.

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Gardeners' World Web User 14/11/2011 at 15:29

I've never thought about the savings from growing from sets. Onions at less than 1p sound good to me!

Gardeners' World Web User 14/11/2011 at 15:57

I've been growing "White Lisbon" onions from seeds for spring onions for salad and omelettes for donkey's years, Adam, and, after thinning the rows out to use, I leave the rest to grow into big onions. It must be the Scots in me! But your advice is needed so much now that money is tight everywhere.

Gardeners' World Web User 14/11/2011 at 17:09

I grew onions last year from sets that my husband bought from a car boot sale for 10p, they grew really well and we had a really good crop. I've planted Autumn onion sets that we got from a discount store in Morecambe for 45p. They are doing very well. So you can still save money if you shop around, you don't have to always buy from expensive garden centres etc. After all, times are hard and friends are few.

Gardeners' World Web User 15/11/2011 at 07:29

Growing onions from seeds are really good option, and its also saves money....Which is the best part....Thanks for the suggestion...

Gardeners' World Web User 15/11/2011 at 19:35

I found some old onion seeds in a tin whilst having a spring clean. In a spare patch of ground, I threw these down with some other bits and pieces and I have just discovered a crop of onions amongst some annual flowers that had was a lovely surprise! I have found more success with seeds than sets but 'donutsmrs' is right - shopping around can really pay off.

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