Once again it is March, and the onion sets have begun to come up out of “the valley”. It is the perfect time for Oklahoma Gardeners to purchase, if they have not already done so, and plant their onion sets.
If you have had some of the experiences I have had with onions, then you have had onions that are not always sweet and have varied in size. You may have also struggled with trying to determine when to harvest your onions? Below, this Red Dirt Gardener will share with you what I have learned about growing a sweet onion in my Oklahoma garden.
The Most Important Day Of Your Onions Life
O Please, an onion has a important day in it’s life? Yes, it really does and it is the day that you buy it. You buy the wrong type of onion and you could not only end up with hot onions but also an onion that does not grow or bolts. Bolting is when the onion puts up a seed head because it came from a warm climate and was planted in your garden while we had cold weather. It may also bolt if a short day onion has been planted in a long day area.
Buy your onions early not as individual plants but as a “set”. A set of onions will be tied together generally with a tag attached as to what type of onion it is. Note, the crates are generally labeled as well. It is a good idea to match the tag on the set to the label on the crate because not every shopper will put them back properly. Also, you will want to make sure the set(s) you selected look healthy and as hydrated as possible.
Where Do Garden Onions Come From
Generally, the growers down in the valley will plant their onions like the Texas 1015 the middle of October, thus the 1015 name. Other onions like the Vidalia are grown in Vidalia GA, the OSO sweet is grown in the mountains of Chili, and the Sweet Imperial comes from California.
How to Pick A Sweet Onion That Will Grow In A Oklahoma Garden
Let me give you a bit of a back ground in an onion’s life so when you go to buy your sets and you read the tag or the label on the crate you will understand what it says and come home with a sweet onion.
Onions are classified by the length of day they perform best in. There are long day, short day and intermediate day onions. For Oklahoma you will want a short day onion. So whether you mail order your onions or buy them in the store be sure they are short day onions. You will have a number onions to choose from. Among them are the Granex varieties, Maui, Vadalia, OSO Sweet, Maui, etc. No matter what you do and no matter how many times the onion’s name has “sweet” in it, if it is a Granex varsity the onion will never be sweet.
One onion that grows great in Oklahoma gardens 
and is always sweet is the Texas 1015. The 1015Y is a wonderful sweet yellow onion. 
If you like a red onion try the red Bermuda…not really a sweet onion but it is good. Do you need onions that have a long shelf life ……try the Spanish Onions.
One more tidbit, Texas 1015Y, denotes that the plant was planted in Texas on October 15th and its color is yellow.
Plant My Onions In 6 Easy Steps
Now thatyou understand why the day you bought your onions is the onion’s most important day, we will get on with planting.
1. Pull any existing weeds out of the bed where the onions are to be planted.
2. When selecting you site be sure the plants will get the proper amount of sun light and be well drained once in the ground.
3. Consider how convenient or inconvenient it is going to be to water your onions. If it is a hassle, you are more likely to not water. Notice that the onions have very shallow roots? They will need water.
4. For small onions, plant the new plants close together. For larger onions provide more space between the plants.
5. Add organic materials and mix well with the Oklahoma clay prior to planting. This will provide nutrients to the onions and the soil. Since clay soil is so compact, the organic materials will begin breaking down the clay so water, oxygen and minerals will be available to whatever is planted in the bed.
6. Finish up with a dressing to help slow evaporation during Oklahoma’s spring winds. I like using mulch I have made by chipper shredding the clippings from my yard.
Fertilizing
You want to use a urea or for those using chemical a 46-0-0. If you use a fertilizer other than this, it will contain sulfur (it will be listed on the back of the bag) and that is not a good thing for your onions. Note:34-0-0 is not the same thing as it has sulfur in it. The reason you want to apply urea/nitrogen to the onions is because you want to promote the growth of leaves. I am sure you are now thinking that is odd, since you are growing onions to have onions not leaves. Well, did you know that every leave has a corresponding ring forming the onion? More leaves = more onion.
Should You Step On Your Onions
This is like talking politics to some onion growers…Here is my take on it. You do not need to step on the tops to start the process of preparing the onions to be pulled. The tops will go over on their own, this is call “bulbing”. Bulbing is initiated by the length of the day and begins your 7 to 10 day count down to harvest. Do not wait till the tops begin deteriorating to harvest.
Once out of the ground store the onions in a shady area with the tops on. I usually gather them into bunches, tie a string around them and hang them in the garage.
Enjoy!
Don’t forget to feed and water the birds!
Oklahoma’s “Original” Red Dirt Gardener