[gilesi]

As a complete newbie I am thinking of planting some onion sets possibly "Red Baron" I have just cleared a bed on my newly acquired allotment and would appreciate any advice - my soil is clay - do I need to add anything before planting ? I live in the south west of the country
Many thanks

Ian

[jambop]

Red onions are much more demanding of weather than yellow ones maybe try Sturon or Stutgartter and try to get some compost into your soil. Repeat I do not recommend a red onion!

[Ivor Backache]

I grow red baron every year. It is a mild onion which I grow for salads. However do expect it to bolt more than white onions (with me its about 25%) and it does not store as well as white onions.
With regards to your soil: clay holds on to the nutrients and also moisture, both important for onions. if it is clumpy clay then it does need some compost/manure to make it more crumbly.

[Goosegirl]

I use onion sets and like Red Baron but it does tend to bolt more and doesn't store very well, if at all. I now grow Stutgartter because I do like a stronger onion but it also has a slightly sweet taste and keeps better. As said, add whatever compost you can get. I find spent mushroom compost is cheap and great for soil improvement by digging it in or using as a mulch. You can get it delivered as a heap or I get it in bags with discount for more than ten, so it works out at £1 per bag. I don't know the weight but the bag is about 3' x 1.5' and I can just about lift it. 

[Fisherman]

Red Baron from seeds seem to keep better than when grown from sets although its getting to the back end of the sowing period now. From seed they usually keep well into April and don't bolt too much either.

[Lesleyk]

I seem to have particularly successful onions - not sure why!  I don't do anything in particular to the soil except sprinkle with chicken pellets a short while before planting.  I get bumper crops (particularly white ones that store easily over winter).  I have even had success with red onions, with all the caveats other contributors have mentioned, particularly that they don't store at all well.  And I always have an overwintering crop, for an early(ish) harvest.