I set my onion sets upright in a tray of damp soil so they can get a good root system before putting outside (The gardens covered in snow at the moment anyway) Is this detrimental to the plants, and if so, why? Thanks, JohnT.
It might work if you take enough soil with the root to keep it well covered when you transplant them. Problem is, the roots on onions are extremely fine and you can tear them off if just pulling them up for transplanting. I'd soak the soil until fairly wet just before transplanting and then scoop up a goodly amount of the damp soil with the onion set... probably three or four times the size of the plant.
I always start my onion sets off in a cold greenhouse, planting them in 40 cell modules using a general purpose potting compost. If I try planting them direct into the ground on my allotment, the birds have fun pulling them up, even though I partly cover them with soil.
Using modules lessens the damage to the fine delicate roots. I plant them as soon as the ground allows me to get on it by using a small trowel to make a planting hole.
Good luck
Hi I have grown my sets that way for as long as i can remember(this is getting shorter by the year) and have had no troubles I think you may have been a tad early but weather should change soon,when you plant out take care of the fine roots and spread them out and cover with a sprinkle of fine soil. Good luck