Red onion bulb - when to plant?

[AppleDapples]

Newbie gardener here. I had a red onion that started to sprout green stalks back in the spring, so I planted it in a good sized pot and put it in the sun. The stalks got about 8 inches tall by late spring/early summer, but then just sort of plateaued in growth, and then by late summer they slowly one by one turned yellow to brown and died. I dug it up, not really knowing what to expect, but it was just a shriveled looking bulb, so I just sort of gave up on it, but noticed that as of last week, it is again growing the green stalks.

I've never tried to grow onions before; I just sort of planted it on a whim with other things I started from seed. Does one onion bulb only yield one onion? I looked online and it is suggested to plant bulbs in spring for zone 5 climates, but that didn't really get me anywhere. I get that growing from seeds will get you onions, but I'm not entirely sure on just what the heck is supposed to happen when you plant one that is already an onion/bulb. Thanks in advance for any responses.

 

[Chuck]

There are 3 ways to plant onions. From seed, from sets (young small dried bulbs) and from seedlings. Seedlings are the best. One bulb or one plant or one seed = one onion. There are two types of bulbing onions. Long day and short day. Onions grow by the length of sunlight per day. I think zone 5 is probably a short day onion. You will have to talk to your local nurseryman to find out what type and varieties will do well in your area. Most real nurserys will have the onion seedlings available when it is time to plant them usually when the ground is soft enough to dig in your area. Seeds are usually planted from Oct-Dec in flats and then set out at the correct time, from Jan-March

 

[AppleDapples]

There are 3 ways to plant onions. From seed, from sets (young small dried bulbs) and from seedlings. Seedlings are the best. One bulb or one plant or one seed = one onion. There are two types of bulbing onions. Long day and short day. Onions grow by the length of sunlight per day. I think zone 5 is probably a short day onion. You will have to talk to your local nurseryman to find out what type and varieties will do well in your area. Most real nurserys will have the onion seedlings available when it is time to plant them usually when the ground is soft enough to dig in your area. Seeds are usually planted from Oct-Dec in flats and then set out at the correct time, from Jan-March

Interesting, so I guess mine would currently be a set, since it basically looks like a small dried up onion. Since it is just starting to grow green stalks again, should I plant it in some dirt and bring it inside for the winter, and then transplant it to the ground around March? How can you tell when its ready to harvest the onion? I'm guessing the edible onion would be separate from the bulb, so you can eat the onion and leave the bulb back in the ground?

Sorry for the bombardment of questions - my only experience with vegetables that grow underground have been with radishes and carrots, which have been pretty straightforward since you only harvest once (and also because I started those from seed and didn't deal with bulbs). Thanks for the help.

 

[Chuck]

Interesting, so I guess mine would currently be a set, since it basically looks like a small dried up onion. Since it is just starting to grow green stalks again, should I plant it in some dirt and bring it inside for the winter, and then transplant it to the ground around March? How can you tell when its ready to harvest the onion? I'm guessing the edible onion would be separate from the bulb, so you can eat the onion and leave the bulb back in the ground?

Sorry for the bombardment of questions - my only experience with vegetables that grow underground have been with radishes and carrots, which have been pretty straightforward since you only harvest once (and also because I started those from seed and didn't deal with bulbs). Thanks for the help.

The small size of the bulb is not what matters. If it was a mature onion when it was harvested all you will end up with are green tops and maybe a flower. The bulb part will not make an onion. Onions are daylight sensitive. They must have x amount of daylight hours per day to bulb and x number of days to mature. I don't know where you are located but being in zone 5 I would guess in the northern half of the US. In the winter it will be a waste of time. If I understand what you are saying this was a mature onion last spring that started sprouting leaves before you could eat it. If that be the case it will not become an onion, all you will get are maybe a few leaves you can use like chives. When you plant a viable (immature) set, it will make leaves. Each leaf will make one ring of the mature bulb. The more leaves the more onion rings and if grown properly the larger the onion bulb will be depending on the variety. When you plant sets the set itself will grow into the actual onion. If you plant seedlings the lower part that has the roots attached will grow into an onion. You can tell when they are ready to harvest when the green tops fold over or in gardening language, break. You then pull the whole thing out of the ground. I presume you got this onion at the grocery store last spring. More than likely that onion came from somewhere in the south.....Mexico, Georgia, Texas, Florida, Calif. etc. If so they wouldn't bulb anyway as they are all short day onions

 

[AppleDapples]

The small size of the bulb is not what matters. If it was a mature onion when it was harvested all you will end up with are green tops and maybe a flower. The bulb part will not make an onion. Onions are daylight sensitive. They must have x amount of daylight hours per day to bulb and x number of days to mature. I don't know where you are located but being in zone 5 I would guess in the northern half of the US. In the winter it will be a waste of time. If I understand what you are saying this was a mature onion last spring that started sprouting leaves before you could eat it. If that be the case it will not become an onion, all you will get are maybe a few leaves you can use like chives. When you plant a viable (immature) set, it will make leaves. Each leaf will make one ring of the mature bulb. The more leaves the more onion rings and if grown properly the larger the onion bulb will be depending on the variety. When you plant sets the set itself will grow into the actual onion. If you plant seedlings the lower part that has the roots attached will grow into an onion. You can tell when they are ready to harvest when the green tops fold over or in gardening language, break. You then pull the whole thing out of the ground. I presume you got this onion at the grocery store last spring. More than likely that onion came from somewhere in the south.....Mexico, Georgia, Texas, Florida, Calif. etc. If so they wouldn't bulb anyway as they are all short day onions

Thanks for all the great info! You are correct, this was a run of the mill red onion from the grocery store that began to sprout in my pantry. I figured I'd throw it in some dirt and see what happened. Now that I know I shouldn't hold my breath for a new onion, maybe I will at least get some chives from the leaves as you suggested. I never even used to like onions, now I can't get enough of them, so maybe this spring I'll see what the local nursery has in stock. Thanks again Chuck!