planted onions and garlic on the 15 Oct. last year- fertilized with 5-10-10 - mulched onions and garlic with 6"of leaves directly out of bagger- did two 30' rows of garlic and two 30' rows of stuttgard onions the same way-excellent results this year- left mulch on this growing season- super onions and garlic. same time planted two rows of stuttgarders with leaves and removed most of leaves in the spring- didn't have enough days in the week to keep up with the weeding- couldn't buy any onions this fall to plant- next spring going to plant onions and mulch with straw or wood shavings - don't recommend using to much organic composted chicken manure- it's high in nitrogen- look for composted manure with higher phos. and potash (N-P-K)-goodluck this coming spring- the key is to buy quality sets right in the begining-HAPPY GARDENING!!!

you shouldn't mulch onions as you would garlic since onions will have a hard time emerging through the mulch. however after the onions emerge there should be no problem with mulching them. i never have used cardboard so i don't know about that. i use straw. i guess if you use cardboard as one would use plastic mulch then there is nothing blocking the emergence of the plant.

The bulbs need air and sunlight. Mulching next to the plant is not recommended. In most cases onions do not handle mulching very well, onions like to have their tops exposed to the air. Mulching also increases the risk of the bulbs rotting.

I have found, and read, that onions will sprout less bulb and more green the deeper it is planted. I grew long-day onions last year and harvested some 2" - 2 1/2" onions. The previous year when I had them a bit deeper, they were all greens and scarcely any bulb. The caution of rot is a good idea in that we have had a lot more rain this year than in others. I will pull away the clippings and let things dru out a bit.