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Gardening in Eagle County

Tom Glass
Vail CO, Colorado
Tom Glass
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Three hundred days of sunshine and it seems we’re sitting in the middle of the 65 days that are cloudy. It’s beginning to get on the nerves of even the natives ” particularly the pasty colored ones no longer interested in the depth of the powder or the base. All this became evident to me in the first half of the Super Bowl while I was barbecuing a massive stack of pork ribs and other assorted meats.

When you’re the plant guy at a party, in addition to being the grill guy posted outside, at some point you’re going to talk about the weather, and most likely about what it’s doing to the house plants of the sometime, and then only socially, supporters of specialized agriculture in Kentucky and the Carolinas.

It seems there’s more than a few people concerned about the effects the lack of sunlight is having on their indoor foliage, not to mention their seasonally affected moods. What to do? By nature being better with plants than people, I’ve got nothing for the chronically bummed by the weather. However, I’ve got one of the coolest cures for plants that are getting stringy, stretched out, structurally unsound due to excessive elongation, ever researched.



I’ve been saving the topic of this column for a time closer to a spring planting date, but cocktail conversations indicate the time is ripe for the printing. I didn’t share this tidbit on Super Bowl Sunday because it sounds like smoke and mirrors. But, this principle was heavily researched at Michigan State University, and is employed by growers all over the world. It is so simple that it seems obvious.

Altering the difference between the day temperature and the night temperature plants are grown in can easily control the height of most plants. Big deal. Right? Well, yeah, it is.



Allow me to elaborate ” and we know plant guy loves to elaborate. The principle is known as DIF, and, quite frankly, I have never received nor read an accurate description of why this works. I have had PhDs and professors speculate as to why, but no research has adequately nailed the why of it all. Nonetheless, it does work, particularly when plants are actively growing.

Simply put, to keep plants short, place them in an environment that is cooler during the day than at night. This is known as a negative DIF. A positive DIF is achieved by keeping a plant warmer during the day than at night, and will cause them to elongate. Six degrees difference is optimum. For those of you that favor equations displaying numbers, consider this: 65 degree days + 71 degree nights = dwarfed plants. It’s that simple; save some energy during the day and you’ll keep your plants in shape.

You’ll know if its working if the plants become a little off color, yellowing a bit, and the leaves cup downward. This discoloration and cupping can be reversed by simply keeping the days the same temperature or warmer than the nights. Wow. In my world, this is big.



Particularly when you encounter the customer that comes in early spring with that look in their eye that says I want to germinate things and buys a fistful of seed packets. The heck of it is, most of them are going to succeed at germinating the seed only to fail at growing a useable plant. I hope upon this reading that no longer occurs.

By employing a negative DIF, impatiens can be grown from seed to a height of an inch tall that possess a bloom and three buds. Seems like a worthless thing to do.

But, if you’ve ever started seedlings indoors, you know that they often stretch toward the light and then promptly fall over only to corkscrew around uselessly on the top of the soil and then most likely die. You can prevent that from occurring using a negative DIF. Some of you more experienced seed starters may know that simply removing a just cracked seedling to a cooler area will prevent some of this stretching, which it does. But you gain a further measure of control using a negative DIF.

Well, you can stick this column in drawer. Using DIF is really as simple as I have described here, but if you plan to grow some of your plants from seed, or want to stop the stretch that occurs during serial days of cloudiness, you can use this as a reference point for digging up more information.

Tom Glass writes a weekly garden column for the Vail Daily. E-mail comments or questions about this column to cschnell@vaildaily.com.


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