As far as I am concerned, it is too hot to do anything outside right now. So, sit in the air conditioning with an icy soda and think forward to mid-February. Are you shivering yet?
Okay, imagine holding a bundle of those little onion starts you buy at the local nursery. My experience is they’re almost indestructible. But, the truth is, if the temperature goes below 20-degrees Fahrenheit and stays there too long, your onions will traipse into the Great Beyond.
While I like green onions, I use bulb onions all the time. The outside temps can’t be much below 50-degrees for bulb formation to take place. Ideally, bulbs form when the thermometer registers between 70- and 80-degrees. When the temperature tops 85, the onions give up getting nice and fat.
According to retired Agri-Life Extension Agent Kenny Rollins, “Onions are day-length sensitive.” Well, who knew?
Some varieties of onions bulb-out when the days are still short and others don’t get up a head-of-steam until we’re at least thinking about the summer solstice. Ask a nurseryman or call the Extension Office to get a list of what bulbs round-out when in your area.
It’s discouraging when lettuce bolts, which is a trick onions can do, too. Did you know bolting to make flowers is temperature dependent? Get this, prolonged exposure to 40-degree weather increases the chance of a bolting onion. Try to store an onion that bolted– yuck. The flower stem, which is right in the middle of the bulb, will rot almost before your very eyes.
For fat, sweet onions, research which variety to plant when, then mark your calendar.
Onions like low acid “sweet” soil (pH above 6). Put fertilizer in the soil about three-inches lower than the root-end of the onion start; then give them the equivalent of two-inches of water every week. It takes longer than you think to add two-inches of water to the soil, so be patient and give your babies a good soaking.
Onion roots are shallow and, left to their own devices, are not very good at seeking out and slurping in water. With any luck this year, Mother Nature will give you a hand. Brad Barton seems to think we might be getting an El Nino winter, which means plenty of drenching from the sky. We’ll see, but come Valentine’s Day it won’t hurt to keep a hose or sprinkler handy for the onions.
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