Sunlight and temperatures in regard to your garden

All garden plants and even flowers and trees are dependent on several factors.

Three of the most important are the temperature, hours of direct sunlight and day length. (By day length I mean hours from sunup to sunset.) All three are important.

Most articles on gardening will focus on hours of direct sunlight, which the plant needs, or partial shade.

Most articles will tell you plants require at least 10 hours of daylight. Basically, this is true, but it's only part of the story. Plants need a basic amount of daylight, but some plants require substantially more.

When I first started to grow onions, I figured it was about the easiest crop as well as the most simple. You just plant the onion and then wait.

I knew we would have to keep them relatively weed free and water them as needed. I also figured we'd have to fertilize them now and then. So I'd give them a shot of Miracle Grow along with some water and then wait.

Then I started to read there were long-day onions, intermediate-day onions and short-day onions. I didn't know that. A great source for information on onions can be found at dixondalefarms.com/.

Short-day onions start bulbing when the daylight hours reach about 10 to 12 hours or so. These short-day onions are for the southern states. Long-day onions start the bulbing process when the daylight hours reach about 14 to 16 hours. These long-day onions are for the northern states.

Those states in the middle of the U.S., such as Nebraska and Missouri, do best if one uses intermediate-day onions. Intermediate-day onions start bulbing when sunlight hours reach 12 to 14 hours.

Onions should be planted early. I try to plant mine a month to six weeks before the last expected frost date, which is about mid-April here in Scott City. So I am planting my onions about March 1, which has about 11 1/2 hours of daylight.

The most important factors with onions seem to be the hours of daylight and getting them started early in the spring. By planting early, they can develop a root system before forming a bulb.

Most experts say tomatoes require six to eight hours of direct sunlight daily and this is true. But what they fail to say is tomatoes seem to require a minimum of 12 hours of daylight, even if this is not direct sunlight.

The six to eight hours are required hours of direct sunlight. So in other words, if your tomatoes have direct light for eight hours and shaded light for another four or five hours, they will be OK.

If you look up aa.usno.navy.mil/data/docs/Dur_OneYear.php, you will be able to get the hours of sunlight for your area. You will need to type in your state and town, but you will end up with a table of daylight hours.

It is interesting that in Minot, North Dakota, on Jan. 1 there are 10 hours and 15 minutes of daylight.

In New Orleans, however, there are 8 hours and 25 minutes of daylight. Anchorage, Alaska, has about six and a half months of days with more than 12 hours of daylight, with there being almost 20 hours of daylight in June.

Here in Scott City, we have about 12 hours of daylight on March 15 or so. In mid-April, this increases to about 13 hours. Mid-May is about 14 hours. Mid-June is about 14 3/4 hours. July goes down to about 14 1/2 hours. Then August goes down even more to 13 1/2 hours. This amount grows and then decreases until about the end of September, when the daylight hours end up being around 12 hours again.

I've grown tomatoes in the fall when the daylight hours got below 12 hours. They didn't taste as good and didn't ripen like they should.

It wasn't necessarily the temperature, which is a factor, but I believe it's directly related to the hours of daylight. Some articles I've read say it isn't, but I believe it is.

With our high tunnels, I could raise tomatoes clear up into December temperature-wise, but I don't believe they would taste good.

The cause, I believe, is day length. I would have to artificially lengthen the days so they got about 14 or 15 hours of daylight.

Turnips want to bolt or blossom when days are short or in the spring and the temperature gets up there. So growing turnips requires fall days. Spinach is the same. I read it is next to impossible to grow spinach in the southern states because of the length of daylight and the heat. Lettuce seems to grow best when days are longer and temps are cooler. We have grown potatoes early in the spring and they do very well. We have planted them later in the summer and they don't seem to grow as big. Beets do best if planted early in the spring. Information says they would do great in the fall, just like turnips. I may need to try fall-planted beets.

Just a side note, which I find interesting, is that chickens begin to lay more eggs in the summer. Come to find out, the reproductive cycle in chickens, or the avian reproductive cycle, begins to crank up as the day lengthens and approaches 14 to 16 hours.

You can hurry up this cycle in the spring by introducing artificial light and lengthening the day. When I worked with thoroughbred stallions in Kentucky, we would begin artificially lengthening the stallions' days in the spring.

We'd leave the lights on later at night and turn them on earlier in the morning. This would get their "juices" flowing, getting ready for breeding season.

Ever wonder why there are a ton of baby kitties in the spring? I bet it's the length of the days more than the temperatures.

Happy gardening.

Until next time.