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Insects are coming to kill your houseplants. Here’s how to stop them.

  • Author: Jeff Lowenfels
    | Alaska gardening
  • Updated: October 20, 2017
  • Published October 19, 2017

In Alaska, it’s time for houseplants. It’s time to take care of them. (Getty Images)

Even the diehard gardener will admit it is time to switch gears and start paying more than lip service to houseplants. Settle in with them. They will need to sustain us for the next nine months.

Lights. The one thing you will always remember about plants from science class is that they need light to sustain themselves. How much is enough in the winter? The saying goes: enough so you can read a newspaper, and I don't mean the digital variety. In my opinion, it needs to be at least a six-hour read, too. Right now, you should be set, but in two months, you will need to add supplemental lighting. Why wait?

Plants. Obviously, you need houseplants. The rule around these parts is that if it is not doing well now, it definitely won't do any better this winter. Toss those dead and dying plants. Sure, take cuttings if you can, but replace them now, not in the middle of the winter.

It isn't hard to find great and unusual houseplants around Alaska these days. From the national chain stores, to supermarkets and, of course, the noble nurseries that stay open during the winter months, there is an ample supply from which to choose. As a general rule, plants with flowers need more light than those that are just sporting leaves.

Shop around. There are all manner of new plants coming on the market all the time. And a lot of the old, standard varieties of houseplants have been greatly improved.

Don't be afraid of orchids: They are cheap enough even if you fail. Their blooms usually last for four to six weeks and they are much easier to care for than those of years past.

Read the plant labels before you buy so you can get an idea of conditions required for good growth. Take your phone and use the internet too. Or ask for help. And, obviously, make sure anything you buy is appropriately protected for the trip home. It is cold out there.

Pests.  As noted last week, when the heat comes on in Alaskan homes, the spider mite populations explode. Be on the lookout for these and for "woolly aphids," which look like little cotton dots. Look for "scale," too, little waxy plates that hide a sucking animal. The later two may take some searching. Do inspect all your houseplants.

NEEM products work on the mites and may get the woollies and scale, but I would seriously consider tossing woolly aphid and scale infested plants. They are hard to clean. Again, if possible, take cuttings which should be easier to clear of these nasty pests. Make sure you isolate any plants which are sick or infested with bugs should you decide to try and eradicate a plague. Duh!

You may also experience the annual appearance of little "fruit" flies coming out of the soil and congregating around sinks (they are looking for water) and flying into your mouth or eyes. Thrips. You can blame these on too much water in the top inch or so off the soil. You can grind up and sprinkle on the soil one of those mosquito dunks or cut a sheet of newspaper to cover the soil so they can't get in or out.

A bit of compost placed over the existing soil of all houseplants will help replenish the microbial life and add nourishment. If you don't have any on hand, buy a small bag. All you need to add is about 1/4 of an inch. After that, your plants won't need food unless they are starting new growth, and, if they are under lights, they very well may do so. Keep an eye out.

Water is best at room temperature or a bit warmer. There isn't enough chlorine in tap water to harm plants, but it can kill microbes, so I would let it sit an hour or more before using it. The best way to water is to take pots to a sink and let them soak for five minutes or so. With this method, once a week should do the trick. Overwatering is the number one cause of houseplant death.

Finally, now is the time to start treating Thanksgiving and Christmas cacti as well as poinsettias in order to get them into bloom. The Thanksgiving and Christmas cactus need to be placed where temperatures are 55 degrees or lower at night and where there is dark for more than 12 hours.

The poinsettias need total darkness for 13 or more hours every day for the next 40 days or so. This should cause them to develop their colorful bracts and then flower. It is always a gamble with plants kept over from previous years because the plants may not have been treated properly since last holiday season. Still, if you want to, try. This is what indoor gardening is all about. Right?

Jeff's Alaska garden calendar for this week

Composting with worms: 12-1:30 p.m. Tuesday, Oct. 24, at Alaska Botanical Garden, 4601 Campbell Airstrip Road. $70 for members, $75 for non-members.

Fall kids camp: 9 a.m.-3 p.m. Friday, Oct. 27, at Alaska Botanical Garden. $85.

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