Last year we tried this method of growing onions. We dug trenches where we planted the onions and as the plant grew taller and taller, we filled in the trenches. This caused the plant to continue growing which created a larger bulb. For us that meant a Normal sized onion.
It’s a little challenging if they start to grow outside their space which is what is currently happening. We should be covering them with more soil but small aisle ways between the rows won’t allow enough space. This is also causing the onions to flower. They stop growing when they flower. We will continue cutting off flowers and treating them as though they will continue to grow. Worst case scenario is we are just storing small onions in the ground until we can use them.
I burnt a lot of last year’s onions in the sun after harvest and previous years they didn’t grow to size. Crossing fingers we grow good onions for sale rather a loss for the 4th year in a row.