Onion Advice Required
DecoyDigger
Posts: 1
Hi,
My wife and I have grown onions on our two allotment plots for as long as we have had plots (20 years). Up until the year before last there has never been a problem but the last 2 years the crops have been terrible.
I always use Sturon from Kings Seeds and they have never let me down. I practice strict crop rotation and keep the onions moving around the two plots we have so as to stop any disease creeping in. We are not alone here, several other members the year before last dug their onions up and threw them away because the just didn't grow.
I usually dig the area over in December and cover with black plastic to keep the weeds down and allow the soil to compact. I have always understood they like hard ground.
Because the crops have been so poor I have started asking around and I am getting conflicting advice.
Some say lime the soil now, others say don't lime the soil feed with rose fertiliser. Some say cover the soil during the winter others say leave it uncovered.
The site is east facing, sloping with sandy free draining soil.
The onions don't die or show disease they just don't grow very big, we used to grow enough onions to sustain us throughout the year.
Any advice would be welcome.
Posts
I suspect that the poor show over the past two years may have different causes. The season before last was very slow - cold temperatures and low light levels. Many veg really struggled that year.
As for 2014 - have you managed to get any organic matter into the soil over the past few years? I would try digging in plenty of good home-made compost and/or well-rotted farmyard manure to improve the structure and all-round fertility. The heavy rains of the previous autumn may have washed nutrients out of the ground, particularly as your patch is free draining and on a slope. I'd also incorporate Fish, Blood and Bone when preparing for planting this spring.
Also, have you been able to water - onions need quite a bit of water while they're growing in order to swell the 'bulb' and we had a very dry summer last year.
Hope that's helpful and good luck with this year's crop
Gardening in Central Norfolk on improved gritty moraine over chalk ... free-draining.
I think that the advice given is very positive and makes sense.
In your position I would test the ground with a test kit, and discover what might be needed.This could pay for the testing many times over by targeting the problem.
I think a lot can depend on the weather. I live in Dordogne where it can be very hot in summer. However, I always manure the site in autumn and fertilise with organic granules when I prepare for planting. I rotovate the soil too, so that it is quite crumbly, my soil was clay but is much better now after years of manure. I know some on this site don't agree with rotovating, but my plot is big and it works well for me. I also water well in the growing period. My onions are big.
I had a friend who grew onions for shows in the UK and she used amazing amounts of fertiliser and water. I think if your plot is sloping with sandy free draining soil then there just aren't enough nutrients left in it. I know brassicas like firm soil, but I didn't think onions did.
Have seen this on a BBC site "shouldn't be grown on freshly manured soil. Instead, dig over and manure the ground several months before planting. If the soil is acid it's worth liming it so its pH level becomes neutral or even slightly alkaline." So that may answer your question about liming. Make sure manure is well rotted and applied some time before sowing or planting.
Have seen this on another site "Soil needs to be well-drained, loose, and rich in nitrogen; compact soil affects bulb development.
Till in aged manure or fertilizer the fall before planting. Onions are heavy feeders and need constant nourishment to produce big bulbs."
I agree with Busy Lizzie regarding compaction of the soil - my family are large-scale vegetable farmers, and certainly the onion-fields I've visited have quite rich and friable soil.
Gardening in Central Norfolk on improved gritty moraine over chalk ... free-draining.
I grew onions with no previous knowledge last year, they did very well on soil that had been cultivated over and then lightly raked to form the seed beds. I would not go as far as saying our clay manages to be friable yet, but it is getting that way.
If it is too late to add manure I think a dressing of well rotted compost now, mixed in with a cultivator in the spring might do the trick. That is what mine grew in on the newly cultivated plot.