Assuming that your onions are a short day length type that are typically grown in the deep south over the winter they should probably begin to bulb up sometime in March and be to full size by late April or early May. They are triggered to bulb by day length and most short day types start to bulb when day length reaches 11-12 hours.

You won't need to stick your finger in to check for bulbing as 2/3 of the onion bulb will form above the soil. Now should be a good time to feed them with a nitrogen fertilizer and stop fertilizing when you see the stem begin to swell at the soil surface. At that point the energy stored in the leaves is gradually being transferred to the bulb.

Thanks for the excellent information. I'm not sure what kind they are, but a local farmer that planted about 10K of them, had an extra bunch, and gave them to me. They will get nitrogen. Thanks again, Ed

You're welcome. I'd bet they are one of the Yellow Granex types better know as Vidalia. Good luck!

I always look forward to mid April when the Vidalia onions show up in the stores here. I make a huge batch of onion rings and freeze enough to last until my onions are ready to harvest in July and I will usually caramelize a bunch and freeze some to use on burgers, etc. during the summer.

Vidalias are the only onions I'll eat, and what a bonus living here in SE GA. Last year we picked up about 40lbs. We pickle a bunch. My wife has a question, and asked me if we can clip a few of our current onion tops to use in cooking? Thoughts?

You probably can clip a leaf or 2 on each plant without doing too much damage to the ultimate bulb size but keep in mind that each leaf equates to one layer on the onion bulb so if you cut the tops it will adversely affect the bulb size.

How far apart do you have them in the 15 gallon pot? You know that Vidalia onions can get to 4-5" or so. If you have them spaced closer together than 4" it might be best to thin them out and use the tops of the thinned ones for cooking.

Actually they aren't the Yellow Granex type. The farmer planted them as well, but also planted some red ones, and those are the ones I got :-( I planted them about 4" apart......a little closer than they are in the field. Yeah, thanks for reminding me that each leaf equates to a layer in the onion. If anything, we'll only clip a few tops for cooking. Thanks again, Ed

Ok,now the plants are getting really large. It's about a 25 gal container, not 15 as previously mentioned. Are they going to start bulbing soon?

I would think they still have a couple or 3 weeks left before they will start to bulb. They look real good though. About how many leaves are on each plant now?

Thanks for the comment. The biggest ones have about 10 leaves.

They are looking good but a little crowded. Depending on variety they should start bulbing around the spring equinox (March 20 +- a week). Harvest ( mature) late April May early June depending on variety. You should be bit earlier than I am in middle Ga.

Yes, I tend to over crowd a bit :-)

The plants are getting really large now, and a couple of them are starting to bulb. I've stopped feeding them but they are still drinking lots of water. Would it be ok to cut back a bit on the water? Am thinking it might be good to stress them a bit to force bulbing. There's a lot of water stored in the tops. .....Or should I just keep watering them well? Thanks, Ed

They need a lot of water when bulbing. Note they are mostly water. Of course just keep them moist not sopping wet. You seem to be right on schedule. At your spacing you might want to pull a few of smaller ones as needed for green onions leaving room for the stronger plants to go jumbo.

Just yanked a few today. The tops flopped over, and were past the point of no return, so we picked them. No expert at onions at all, but they look great to me, very excited.

That's a beautiful harvest! Well done!

Final post on the onions. Might braid them though, and take one more pic.