pointer80
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Starting Onions With Heat Mat

Ok all, This is going to be my second attempt at starting onion seeds indoors. The first ones came up but not very well. I put them on heat mats and don't know if they got too warm? They are still sprouting but very slow and sporadic. I am not going to use heat mats this time. I am also going to use jiffy seed starting mix instead of the custom mix I used the first time. Any advice would be appreciated. Thanks.

gumbo2176
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I prefer to use onion sets for harvesting green onion tops as they grow and for them to grow into nice full onions. I've found seeds tend to only make green onions tops with stalks more like a leek in my part of the world, which is the deep south. Your results may vary, especially if you consulted a local nursery in your area and got their advice on growing onions.

Right now I have about 200 of each, red and yellow onions growing in my garden and I'd venture to guess if I harvested only the green onion tops right now, I'd have 4-5 gallon bags of chopped green onions for later use. As of now, the bulbs are only starting to form, and hopefully by the time the tops die back, they will be fully formed bulbs that I can store for later use.

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digitS'
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My onions were started long ago in the greenhouse, unheated at that time.

Seed is sprinkled and covered lightly in trays. They are somewhat of a bother because I protect the soil from freezing by moving and covering them with a tarp.

I wish that they could go out into the garden now although they aren't much bigger than the size of the cartridge in your ball point pen. The garden soil is saturated with spring rain and there will be more freezing after the clouds move on. Right now, the flats have just been moved to my "sweet spot," outdoors. They will be moved back to shelter when frosts come.

There are both bulbing types and bunching onions. I may sow seed in the garden for additional onions but it's more likely that the seed will be for shallots.

Steve

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rainbowgardener
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When I plant onion sets, I do it in the spring. For onion seed, I plant it in the late fall to over-winter. That way it has a very long growing season to make onion bulbs.

Vanisle_BC
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rainbowgardener wrote:For onion seed, I plant it in the late fall to over-winter. That way it has a very long growing season to make onion bulbs.
Now why didn't I think of that? I do it with leeks; why not onions. Maybe they're not as hardy - do you protect them in any way? My leek-lings stay out all winter/all weather in shallow box "seed beds."

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jal_ut
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Can't keep onions in the ground here. The ground freezes and you have lost your onions. For large onions I get onion sets from the garden store and plant the sets in the spring. For loads of little green onions I plant a row of seeds in the spring.

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digitS'
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I've talked about this on the forum before. The companies that sell onion plants may include this in their instructions for planting out, as well. Subjecting the plants to too severe cold may encourage some of them to bolt to seed prematurely rather than forming bulbs.

That was my experience ~ sometimes ~ with sowing Walla Walla seed in late August. I tried this several times and the plants would survive the winters. Then, a variable number of them would bolt to seed. The final try. I figured that there was just too much sub-zero weather and bolting was nearly 100%.

With purchased Walla Walla plants, I wasn't setting them out in sub-zero conditions. Still, a few of those pampered Texan plants might bolt instead of forming bulbs.

Steve

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jal_ut
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Onions are day length sensitive and will bulb when the daylight hours are a certain length. Hence we have short day onions for the South and long day onions for the North. Here if I want large onions I must get some onion sets, which are little dry onions about marble sized, and plant them early in the spring. If I plant seed in the garden I will get loads of little green onions and if let go full season they will make walnut sized dry bulbs. Try some things and have fun.

imafan26
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You do have to choose varieties for your zone and plant them at the right time. Most seed onions are planted in the fall and sets are used for Spring onions. I only plant from seeds since the onion sets and some other plants like tulips, iris, dahlia, june bearing strawberries are not really suitable for Hawaii. Tulips and daffodils can be forced. Dahlias will grow from seed but unless the tubers are dug up and put in the refrigerator to winterize, they will never come up again. However, asparagus, amaryllis, gladiolas, daylilies, some other lilies, canna, and a few other things that don't need long days or cold weather can live quite well here as perennial garden plants without digging them up.

As a side note, local soil and microclimate matters. Vidalia onions only grow and taste sweet because of the local conditions of soil and climate in Vidalia, Georgia. Hawaiian sweet Maui onions are grown in Kula, Maui which is on the slopes of Haleakala and the soil and weather produce very sweet onions. The seeds are the same as Texas granax. Texas onions are sweet as well and usually bigger. The problem with sweet onions are their seasonality. The taste changes after a couple of weeks in storage unless you have a cool place to store the onions. The northern onions store better than the short day onions.

https://garden.org/learn/articles/view/282/

pointer80
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Thanks all



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