Onions grown from sets generally will not be as big as those grown from plants. Also, May is much too late to plant for your area.

I would suggest setting out plants in early to mid April, planting about one inch deep. Feed them with a high nitrogen fertilizer about two weeks after planting and again about one month later, and keep them well watered and weeded (a thick mulch is helpful). Spacing should be about six inches between plants and twelve inches between rows. Do not knock the tops down - let them fall naturally - and harvest when the tops are down and mostly yellow/brown.

Most important, be sure to buy large onion varieties, and ones suited for your latitude (long day type).

TomNJ

I have a similar problem, but this isn't the first time I've planted onions. I used to get baseball-sized onions. The last two years, including this year, the onions have been quite small. We've gotten plenty of rain, I've been weeding them, and fertilized. Am I missing a nutrient in my soil?

i agree may is too late. also sets are a poor choice. either start from seeds or at the least buy plants locally not mail order.

what was the spacing? you did not tell us.

what variety? baseball sized is large and not all onions are that large.

soil needs to be rich and have good drainage free from rocks.

onions require 1" of water or rain a week.

tom

I planted them in November and now the green stalks are falling over. The onions are very small. I did put fertilizer in the soil before planting the set and I have given them more twice...Thank you