Hilling Onions

[Durgan]

Hilling
"Onion bulbs emerge from the soil as they grow. Lightly hilling bulbs will reduce the amount of sunburn to the onion, will help maintain moisture close to the roots, and will reduce weed competition."

I grow a few vidalia onions (no sting raw) and some other bulbing types. I have observed the bulb emerges from the soil almost fully exposing the bulb at the end of the growing season. Now I hill the bulbs and feel more comfortable. The spider roots are very shallow. I have also found mulch serves the same purpose as soil in prevention sunburn.

You view and practice Please?

 

[Meadowlark]

Sunburn just isn't a problem here in East Texas...especially if the onions are planted about 6 inches or less apart.

I do the exact opposite on the dirt...that is I pull the soil back away from the bulbs to encourage bulb growth. I pull it back all the way to the roots just leaving them covered. Some roots are shallow, but many are deep, very deep and provide anchors for the plant as well as nutrition.

I start this process of pulling the dirt when the bulbing is in full swing. Dirt on the bulb inhibits bulb growth. I've experimented for years on this question and have concluded beyond doubt that pulling dirt, or at a minimum loosening it, around the bulb adds, in general, up to 20% growth in bulb size over not pulling....and I'm confident that % reduction would be even significantly greater with onions hilled up.

I raise 1015 onions and believe them to be the sweetest, best storing, and largest bulbing onions available on the market today. Onions with bulbs exceeding 2 pounds are the target and each year many, many achieve that. The largest I've grown is over 4 pounds of bulb.

The picture below shows the tool and technique I use to gently remove soil around the bulb. The tool is simply and old hoe with part of the business end removed.

This is the stage where I believe dirt removal is most critical (4-6 weeks to harvest):

Results for 2014 :

Results for 2015 :

Largest onion this year (well over 4 pounds) :

 

[headfullofbees]

Onion roots are not shallow, it's just that they are first to die back.
They can reach a length of 30 inches.

 

[Meadowlark]

Some are shallow...right on top of the ground...as I said, others are very deep anchoring the plants. When pulling dirt, its important not to damage the shallow roots which are critical to bulb growth. Likewise its important not to bury the shallow roots too deep if hilling.