|L-R: 1015Y, White Bermuda, Southern Belle Red,|
Yellow Granex, & Texas Early White
Nitrogen is a good thing for onions. The bulb isn't a root structure, but an enlarged part of the leaf, and since each leaf corresponds to a ring of the onion, you want leaves. LOTS of leaves. Which means nitrogen and planting early so they have time to make as many leaves as possible before the daylength triggers bulb production. The other macronutrients are important, too, but nitrogen is key. And planting early.
We didn't get Contessa this year. Instead, we got Texas Early White, an open-pollinated variety new to the market this year that's supposed to be disease and bolt resistant and a really good keeper. The sets looked nice and small and the open pollinated part turned me on, so we planted quite a few of those. I'm looking forward to seeing how they do.
The other types were 1015Y, Yellow Granex, White Bermuda and Southern Belle Red. The Yellow Granex outdid the 1015s last year, but the 1015 sets were big and they bloomed a lot. This year the reverse is true, so I'm betting the 1015s will do better. Last year, Contessa did a bit better than the White Bermuda, but I think those sets were also large. This year, all the sets but the Yellow Granex looked really good, all nice and thin.
In case you were wondering why I'm seeming to say that big sets are bad, here's the scoop. Bulbing onions are biennials, which means they'll bloom in their second year. Unless you want to save seeds, blooming in bulbing onions is bad. It takes energy away from bulb production, forms a tough flower stalk that is a pain in the ass to cut out of the middle (and a pain in the ass to pick out of your teeth if you don't), and bloomed onions don't keep as well ~ they tend to rot from the middle out. So you don't want blooms.
After you plant the sets out they'll be exposed to cold over the next couple months, and when temps warm up, the large ones will think they're two years old and will be more apt to bloom. Small ones, smaller than a pencil diameter, will be a lot less apt to do that. It's counter-intuitive to do this, pick the small ones. One would think that you'd want big ones to get a jump on the growing. Nope. Little ones. Size does matter here.
UPDATE 1-22: The day after I planted them, it rained. I hurried out after work to look at them and they were all standing straight up in little lines like little soldiers. Too cute! And here they are two weeks later.
Those are the Southern Belle Reds in the bed in the front. You can see that they've already started elongating present leaves and putting out new ones. Exciting!