tedln
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Onions!

I planted some Texas Super Sweet onion seedlings in late summer, early fall of this year to find out what they would do growing late in the year. They grew well and produced large green onions, but did not form large bulbs. I know if left in the ground through the winter. The plants would quickly bolt and flower in the spring without producing large bulbs.

I pulled the onions today and trimmed the green tops to about 3" long plus I trimmed the roots off each plant. I am thinking about letting them dry some into January and replant them. I may simply eat them. If I leave them out of the ground and allow them to dry a little, will they still only bolt and bloom in the spring or will they produce bulbs?

Ted
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TWC015
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This probably depends on the size of your bolts. If they are the size of sets you purchase, they may do fine; if they are much larger, then they will probably flower.

If you have room, I would plant at least some of these just to see how they do.

tedln
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TWC015,

Thanks for the information. Are you saying the size of the set or seedling when planted is what determines if an onion flowers or if it produces a larger bulb? I've noticed when I buy bundles of seedlings for planting in early spring, they usually tell the customer to pull and eat the larger plants first because the smaller plants will produce the larger bulbs.

I had assumed being exposed to freeze/thaw cycles in the garden is what determines if a seedling bolts early and blooms or produces a bulb before bolting.

Ted
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TWC015
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I researched this subject on the internet, and I have found that the larger the plant when they are exposed to the cold, the higher the amount of bolting.

Yes, the cycle of cold and warmth does cause bolting, but only in plants that are large enough. The plants that have a neck smaller than a pencil are supposed to be the best, probably because these are not mature enough to reproduce, therefore not affected by the cold as much as large plants. This is the same with sets because they are the second year and generally the smaller the set, the better the chance it wont bolt.

I found most of this information from the Texas A&M University. They have some great information on growing onions. Here are a couple of links:
[url]https://aggie-horticulture.tamu.edu/archives/parsons/publications/onions/oniongro.html[/url]

[url]https://aggie-horticulture.tamu.edu/archives/parsons/publications/onions/onions.html[/url]

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jal_ut
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I have no experience with the variety, nor with growing in Texas, but I will second what TWC015 said about the size of sets. I like sets to be about the size of a marble or smaller. If they are larger, they are much more likely to bolt. You could put some of the smaller ones in a bag and refrigerate them for 2 months then go plant them.
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jal_ut
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BTW, a few onions going to seed is OK. You can save the seed to plant next year. I usually plant a couple of large onions just to go for seed.
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tedln
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I allowed the onions I pulled to dry for a few days. Most of them were more than 1" in diameter. I planted them again today. I just want to see what they will do in the spring.

The Texas A&M web site is a great site for onion information. They developed many hybrid varieties from the Granix onion. My favorite is the 1015 variety which I plant every spring and get large, super sweet, onions from. The only problem with them is the fact that they are not a hard neck and early spring wind storms will break the tops over and the onion stops growing. Because they contain so much sugar, they also don't store well. I usually pull them as needed. They usually have enough with the tops broke over to keep my family and neighbors supplied until mid summer.

The Texas Super Sweet is also a granix hybrid, but it is a yellow onion. It is actually produced in Georgia for distribution in the southern states. I'm sure they would be great onions if planted in the spring because they have a hard neck which won't break over unless a tornado hits them. They also have a high sugar content and will not store well.

I've never tried to grow from sets. I always plant the tiny seedlings. When you plant the sets, do you only plant the root end about 1/4" deep as you do with the seedlings?

I may try sets next spring if I can find the varieties I like.

Onions can do some weird things. Out of curosity, I also planted some of the root caps I removed from the onions I planted to see if an onion will grow from the root cap alone. I've known of people cutting large onions in half from end to end. They then plant the onion halves about four inches deep with the cut side down. They harvest clumps of green onions a few months later. The clumps can be broken apart and the small onions can be replanted to produce large bulbs.

Ted
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garden5
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Well, I'm not too informed about growing in the south, particularly with day-length sensitive crops like onions, but I'll have a go at this.

Temperature does have to do with whether or not an onion bolts or not. However, to my understanding, it is the day/night lengths that cause bulb formation. Perhaps you planted them at the wrong time of year for your area? Is this the time you normally plant onions?
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tedln
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Garden5,

Thank You! You are right. I'm doing some things at exactly the wrong time of year. The best time to plant onions in my geographical area is early spring. I planted some onions this fall to find out what they will do. I am doing things wrong, but I enjoy finding out what will happen when I do things wrong and possibly how to change things done wrong to things done right but a different way. Most of my ideas don't work but it is fun finding out.

Ted
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Gary350
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I am trying to learn how to grow onions too. I just finished reading how to grow onions on about a 20 web sites. There are short day onions, long day onions and medium day onions. I probably should be taking notes on paper at my age my short term memory sucks. I notice a site that sells onions has them listed by geographical location you Latitude point on earth. Here is a link to find your Latitude.

https://itouchmap.com/latlong.html

The closer you are to the equator the shorter the days are in the summer. As you get closer to the poles the days get longer. If your far enough north the sun does not do down at all during the summer it just goes down to the horizon then comes back up again they have 24 hours of sun light for a month or so.

Short day onions have a long season 115-135 days but began bulbing with 10-12 hours of sun light. These are normally grown in the winter for spring harvest.

Some of the long day onions will mature in as few as 75 days. They are called long day, because they need 14 - 16 hours of daylight to bulb.

Hot weather causes them to bolt. One web site says cut about 2" of the onion tops off and they will not bolt. Another web site says to bend the top over they will not bolt.

All the web sites say onions need lots of nitrogen, about 1 cup ammonium nitrate per 20 sq ft every 3 weeks starting 3 weeks after the sets have been planted and stopping 4 weeks before harvest.

Several web sites say onions need sandy, fertile well drained soil. Hill up the soil a few inches before planting. Do not completely cover the onion set you want the top tip end sticking out of the soil. The larger the bulbs gets the more water the plants need. Be sure to give the plants plenty of water the last 4 weeks.

One web site says if you live in the south plant your short day onions in the fall. Put manure in your onion bed plant a row 3 onions wide 4" between each onion and harvest in the spring. Onions can take a certain amount of cold but if the temperature drops too low it can kill the onion.

One web site says plant your onion sets in potting soil inside the house 3 weeks before you plant them outside to get an early start. Once the set grows roots and a small top plant them outside. Put 1" of potting soil in a tray keep it wet. Set the onions on the surface of the soil 2" apart so only the bottom end touches. When it grows roots and a top shake off the soil transplant to the garden.

University of TN says if you put gympson in your soil it improves root crop growth about 3 times. They collect scrap sheet rock pieces.

Onions are not very good at supressing weed growth, and if regular weeding is neglected they will easily be out competed for nutrients. This will result in your crop becoming stunted.

Onions appear to be tricky to grow depending on your Latitude and weather conditions. Even after reading online for 2 days I am not 100% sure what to do. I am pretty sure I need to buy short day onions. April 20 is usually our last frost late March is ususally our last freeze. December days are about 10.5 hrs long. March 21 days are about 13.25 hrs long. June 21 days are about 16 hrs long. The way I have it figured I need to plant my onion sets about the end of February because days will be 10 to 12 hrs long in March and hot weather starts mid June and Desert Hot conditions start about July. I should probably root my onion sets inside in potting soil for quick start outside. I need a 4 month growing season if my onions sets are planted the 1st day of March I should be able to harvest onions about the 1st day of July.
Last edited by Gary350 on Sun Dec 12, 2010 5:51 pm, edited 1 time in total.

tedln
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In most areas, the garden centers sell onion sets and seedlings selected for the latitude they are sold in. I don't think a garden center in my area of North Texas would be selling long days onions. Since I know the varieties I want to plant, I always simply ask for those short day varieties.

I've used the sheet rock trick before, but not on my onions. It works well when pulverized into gypsum powder as a calcium supplement for my tomatoes. You need to always make sure the wall board is manufactured by an American company. A less expensive product has been sold in the United States manufactured in China. It has some really nasty products in it and has made some people really sick when the wallboard was installed in homes.

Ted
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jal_ut
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The nice thing about onions is that you can use them at any stage of their development. Both tops and bulb are edible. If they don't bulb, eat green onions. Plant plenty planning on using some as green onions and let some go for bulbs.

Short day onions for Texas for sure. I am not sure about Tennessee. See what the local garden stores suggest. Contact your extension.

In Tennessee you could probably plant about March 1 to 15 and do well. Maybe even in February?

Here is what I do: Plant April 1 or first opportunity after that date. I just plant on a flat field. No Hills. Make a furrow with a hoe and put the sets or plants in the furrow. Sets get covered up with an inch of soil. Plants get the roots planted about 1.5 inches below the surface. Place the sets or plants 4 to 6 inches apart. They respond well to good fertile soil. I water mine once a week, a good soaking. Keep the weeds out. If you notice flowers forming snip them off. Do not bend the tops. When they are done growing, they will fall down. After the tops fall over and start to shrivel up, you can pull them and dry them. I usually pull mine about Sept 1. So you see ...... about 150 days.

I am at 42 degrees North Latitude. Long day onions here for sure.

I usually plant some onion seed too. I direct seed where they will grow. Some like to start them in flats, for later transplanting, but that is just more work for me. Same goes for starting sets in pots, just plant them where they will grow.
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garden5
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DDF, I'll have to take issue with you on that one. Perhaps some of the dedicated nurseries sell the appropriate day length onion for your area, but around here, I can go into a lowes or a walmart and they will have 4 types of onions: 3 short-day and 1 long day :lol:. Something tells me the the buyers for the big-box stores live in the south :roll:.

Gary, here are some threads on growing onions from seed you may like to read:

[url=https://www.helpfulgardener.com/forum/viewtopic.php?t=25345&highlight=growing+onions]Zone-5 Onions[/url]

[url=https://www.helpfulgardener.com/forum/viewtopic.php?t=22213&highlight=growing+onions]Starting Onions From Seed, Any Experience Here?[/url]

I started my onion seeds indoors about 8-10 weeks before I planted them out. I grew them in front of window light with a aluminum shield behind them to help reflect some light. I gave them only water. I cut the tops back to 4 in. whenever they got long. I did loose about 1/4-1/3 of my crop, due to seedling dying. When I planted them out, they were extremely small; they had maybe about 3-4 leaves each. They looked like blades of grass :shock:.

However, about 3/4 of them formed medium sized bulbs, with a few of them good size (and that was in marginal soil). The store-bought starts (which were much larger) I planted did perform consistently better, though. I suspect that if I grow the seedling under lights and give them some weak fish emulsion to get them bigger when I plant them out, I will get much better results.

Good luck with yours.
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jal_ut
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[img]https://donce.lofthouse.com/jamaica/onion_4.jpg[/img]

Just to give you an idea what to expect:

On the right some Spanish Yellow onions that were grown from sets.
On the Left are two Big Daddy onions grown from transjplants.
Top center are some yellow onions grown from seed planted directly in the garden.
Bottom center are some bulbils from the Egyptian onions. You can plant these bulbils and grow loads of nice green onions.

[img]https://donce.lofthouse.com/jamaica/onion_fm_seed.jpg[/img]

These yellow onions were grown from seed planted directly in the garden. They were planted in April and harvested late August.
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digitS'
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I don't really get away with direct-seeding onions.

One place, I like to grow them gets a fair amount of afternoon shade. The chickweed loves it there! I can't hardly get the chickweed out of the onion seedlings without uprooting them.

Another location is far more open to the sun but there's a chance that bindweed will show up in any bed. I can't very well leave those plants to grow amongst the onions.

So, I seed in flats and wait until the last possible moment (or, what seems like it to me) to set the transplants out. That gives me a chance to do a couple of weedings before any onions are in their beds. The sweet onions don't do quite as well as the plants I buy out of Texas. Still, they certainly do okay.

Onion sets are a different story. I put those out as my earliest planting. They can compete with the weeds and I pull weeds around them since they get such a good start.

I grow Walla Walla onions every year in my 48°North latitude garden. I have been surprised to learn that a gardener in San Diego grows them also! I'm not sure if Walla Walla would be a good choice everywhere. A North Carolina gardener wasn't very happy with them.

I grew Granex onion from seed one year - just wanted to try . . . They bulbed up so early that I don't believe that any were larger than a 50¢ coin. It isn't that the short-day onions won't grow here -- they just won't grow for very many days.

Long-day onions in the south may be a completely different story. They might never form bulbs - I don't really know.

Steve ♪
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