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Snow or not, it’s time to turn on grow lights for your indoor plants

  • Author: Jeff Lowenfels
    | Alaska gardening
  • Updated: October 25, 2018
  • Published October 25, 2018

The experienced reader might have noticed that so far this season, I haven't said a word about setting up supplemental lights for your plants. It is true: I have been holding off due to the weather.

But it is time for readers to fire up their grow light systems and start using them on indoor plants.

Here is the point: We may end up with a permanently warmer climate in the 49th state (and I believe we will, unfortunately), but we will still experience the annual loss of daylight that announces the approach of every winter. Unless I am mistaken, our location with respect to the sun is not changing. So if you are not already, get used to it!

I realize that many are new to Alaska, and to these readers I simply state: You really must have some sort of light system so your plants will not have to struggle through the next eight months. You need to protect your investment in your plants. And as a bonus, you will use these same lights to start your seeds for next summer's garden. This is how things are done here.

To those who, however, have been lining their birdcages with this column for more than a year, don't even try to tell me why you still don't have winter lights under which to grow or maintain your houseplants. What? Really? And for those who have been loyal readers for years and years of my insisting that you must set up some sort of lighting, what gives?

In truth, I have been pleading, berating and cheering on readers for more than 40 years, sort of a horticultural "Lights! Plants! Action!" call. When I first wrote about lights, I had no idea it would be so difficult for any Alaskan to admit that when it comes to winter, we live in the land of the Noon Moon. (Alert: T-shirt rights belong to my friend Wayne Lewis.)

Unlike some of the other advice I have given over the decades, not one person has ever, ever said adding lights in the winter was a mistake or that they wished they had not listened to me, yet I even failed to convince when the news came out that these lights help our mood too. There is simply no downside. If there is, I want to hear about it!

So get out your lights and fire them up. Those who don't have any, get going. Whatever suits you, from the two-bulb fluorescent fixture to newfangled T-5 lights or some that are even more complex. You can find what you need in specialty lighting stores, hardware stores, grow shops, some nurseries and all chain box stores' lighting departments. No excuse.

You have to have a timer to turn these lights off as well. In the past I have emphasized a timer's utility so that you don't have to be home to do it. However, there is another reason. Plants that love short days include popular ones grown here (chrysanthemums, kalanchoe, Thanksgiving and Christmas cacti and begonias). They do best with less than 12 hours of light per day. It is necessary, in fact, for them to set buds.

Vegetable plants, on the other hand, especially seedlings, are long-day plants. They do best with 14 to 18 hours of light. If your plans are to grow vegetables indoors (and that includes cannabis), be aware and set the light timer accordingly.

Fortunately, "house" plants, as with all our leafy friends, do well in most any light from eight to 12 hours of light winter or summer. Set your timer so you are not woken up by the lights going on, unless you want to be!

Regardless, I am pleading on behalf of all of your indoor plants: Set up the supplemental lights for the winter. It may not seem like winter temperature-wise outside, but the diminution of light is telling them it is time for you to act.

Alaska Garden Calendar

Wreath-making: Alaska Botanical Garden. It is fun to visit in all seasons.

Houseplants: Start checking for spider mites at the base of branches. You will see their fine webbing.

Watering: As the heat comes on, the water needs of plants change. Don't let yours dry out.

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