Onions - what am I doing wrong?

mr chips

Started growing my own stuff about four or five years ago, and for the most part I've been happy with the results and learned plenty of things along the way. One thing I haven't figured out yet though is why my attempts at growing onions are generally only moderately successful at best. Usually I plant individual bulbs a reasonable distance from one another (e.g. 6-8 inches apart), a few inches down in the mix of compost and soil I have in various growboxes I made from timber. Sometimes I set them to surround a line or two of carrots, in an effort to protect those from carrot fly. I've also had a go at growing from seed, sowing those just below the surface as they're tiny.

Whatever method/approach I use seems to produce the same less-than-satisfactory results - the bulbs generally don't get to a greater diameter than maybe two inches, often less. They do put out healthy-looking stalks over the course of the season, which would make you think there were monster-sized bulbs under the soil. It seems to make no difference if I pull them earlier or later, with stalks six inches above the soil or three feet above it, or even if I leave some in till the following year or let them flower & go to seed ...

I do occasionally probe around the top of the odd one (i.e. I'm not poking & prodding every single one!) to try and gauge how the bulb is growing or if it might be ready to pull, but am always careful not to break any root hairs etc. Often I think I've got a bigger one, only to find when I pull it that the onion has actually divided into two or three smaller bulbs. I've even tried separating & transplanting some of these, and have also tried both rotating (i.e. planting new bulbs in a different location from year to year) and leaving some boxes with just onions for two or three years in a row. I'm reasonably successful at preventing pests (mainly slugs & birds), between netting/crushed eggshells/coffee grounds etc. Yet most of my onions end up no bigger than a bulb of garlic.

Maybe I just need to sow out a different variety, or adopt a stricter planting schedule? Use more compost/less compost? Open to suggestions!

RebelButtMunch

Do you let them flower?

amber2

RebelButtMunch wrote: »

Do you let them flower?

Noticed that this year, our hens went into the onion patch and knocked some stems during the summer and those onions seem to thrive in comparison to the upright stalks and the ones that flowered were a disaster had a tough stalk all though the middle.

mr chips

Have tried both - letting some flower, plucking the incipient seed heads off others as soon as I spot them. I don't mind letting a few go to flower as the bees love them (not sure I'd be keen on the honey though!) but from what I've seen so far, once that happens the bulbs have no chance - presumably the plant is putting everything into the head by that stage, and the stalks of course get more woody. As amber2 says damaged ones sometimes seem to do better, e.g. if a slug has managed to get a nibble further up or a bird has reached the beak through the netting. I wonder would it help if I clipped them at the top after they reach say 6 inches?

RebelButtMunch

I let my red onions flower bar one. That one came out normal. The others hardly grew. My white onions didn't go into flower and turned out huge. Next year I won't allow any of them flower

JPA

Are they too much under the soil? They should just be pushed firmly down so the roots can grow.

mickdw

We trim the stalks back from about a foot high down to half that - 2 times or 3 over the season. Forces more energy into the bulb.

mr chips

Generally when sowing bulbs I put them in so that the top of the bulb is an inch or two below the surface, depending on the size of them. I'll try trimming the stalks from now on, seems to make sense.

magicbastarder

mickdw wrote: »

We trim the stalks back from about a foot high down to half that - 2 times or 3 over the season. Forces more energy into the bulb.

would be interested to hear if there's any truth in this, as it reminds me of the practice in tying up daffodil stalks after they flower - as similar claims are made re pushing energy into the bulb - and this is not true (for daffodils).