You don’t really have to know a lot to be successful with onions. I can state that with authority because I was successful growing anywhere from 1,000 to 3,000 onions each year for more than 3 decades and I didn’t know much. See my post Growing Onions – Top 3 Guidelines for Success.
A couple of things came about that made me want to know more.
- I wanted to break away from being dependent on purchased onion transplants.
- And I became interested in trying other varieties.
The more I read about hybrids (not only onions, but any vegetable) having less nutritional value, the more I wanted to find open pollinated varieties that would do well for me.
So I started buying onion seed and sorta went crazy. I’d get so excited when I was reading catalogs – on and offline – I’d forget to make sure that the variety met the criteria that I’d set.
- Old Seed vs. New Seed
More than once I purchased onions from a supplier that was running a year end sale. I was sent onions for that year rather than those specifically packaged for planting the following year. (Example: Without realizing it I’d be buying 2014 seeds in December of 2014 to plant in 2015 rather than seed for 2015.)
Some vegetable seeds, if stored in a cool dry place, can remain viable for 3 to 10 years. Onions are not one of those.
You can get sporadic germination from second year onion seeds, but there’s no guarantee. To get the best results you need fresh onion seed each year.
In all my experimenting with onions this year, I’ve tried to start a lot of last year’s seed since there’s no point holding it over. Germination was practically nil in some varieties and very sparse in others.
- Suitable Day Length
I’m fortunate that here in Virginia (latitude 37.95ºN) I’ve had success with all categories of onions: Long Day, Intermediate and Short Day.
I did however go a little crazy last year and order too many short day varieties when I needed more long day varieties. Many of the long day onions are good storage onions and few, if any, of the short day onions last very long.
That’s usually not a problem for me. For example, last year I ate all 400 of my short day onions before I had to worry about storage. They were sweet and delicious!
Number of Daylight Hours Trigger Bulbing
If a variety falls into the short day category, it’ll need from 10 to 12 hours to trigger bulbing. Last year I was late getting my short day onions in the ground and bulbing was triggered before the plant had time to grow as many leaves as usual. So overall, my short day onions were smaller last year because bulbing took place before they could grow more leaves.
Keep in mind that each variety, even within the same long/intermediate/short day category, has its own number of hours that will trigger bulbing. For example, some short day onions take 10 hours. Others might take 11 or 11 1/2 or 12 hours.
Information on exact number of hours is hard to find. I’ve seen some, but not much.
This might become very important if I unknowingly order a long day onion that takes 16 hours of daylight to trigger bulbing because we never get that many hours of daylight. Our max is 14 hours the first week in May. (I do well with the long-day onion Copra. Obviously it must only need 14 hours of daylight.)
You can get a chart telling you the daylight hours your area has on any given day by going to http://aa.usno.navy.mil/data/docs/Dur_OneYear.php and typing in your City and State. I saved the chart for my area to my desktop and that way I have it on hand.
This year, I’m taking my time and thinking it through so the seed I buy will meet the criteria I’ve set and give me the best chance for success.
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