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Jeff Lowenfels: Prepping outdoor plants to come in for winter

  • Author: Jeff Lowenfels
  • Updated: September 28, 2016
  • Published August 21, 2014

There is little doubt we are heading down the path toward the indoor gardening season. Surely there will be several more weeks of outdoor growing, but the end always comes to outdoor gardening in Alaska and it pays to prepare for it early. That being the case, now is the time to consider growing some of your outdoor plants indoors this winter.

There are problems taking summer plants and trying to make them survive indoors in the winter. The first and foremost, even more important than if the plant will make it indoors after a summer free-ranging it in your yard, is the possibility of hitchhikers from the animal kingdom. All manner of things from slugs and snails to aphids and more can come indoors with your plants. This is the primary reason you should consider acting now, instead of when a frost is predicted. It takes time to prepare plants you wish to keep over the winter.

What plants might you consider? Almost any annual will survive for a while, if not all winter, if properly transitioned to your indoor environment. Coleus, impatiens, fibrous begonias are some of my favorite flower candidates, but you are not limited to these by any means. Among vegetables, tomatoes can do very well when moved from greenhouses to the home.

The process of moving plants indoors is sort of a reverse of the hardening off process. Start with plants in the ground that you want to keep. Pot these up this weekend to first, see if they will survive in pots and second, to give them some fresh, well-draining, full-of-compost soil. Let them sit on a deck or porch for a week, right next to those plants that are already in pots or containers that you also want to move indoors.

At the very least give the leaves a good hard spray of cold water every day. Best, spray all the plants and their soil with AzaMax or other neem-based product. During this week, look for and then clean off any slugs, insects, dead leaves and stems. You may even want to set a slug trap near your plants.

After you are as sure as you can be that you have taken care of all the visible critters, move your plants indoors where they will be totally isolated from your houseplants. A garage with a window or lights is a good stopover. Spray them again and continue to observe the plants for signs of insect life. I like to wait 10 days or so before deciding if the plants can come all the way indoors, but at least a week is needed to ensure (as well as one can) that the plants and soil are "clean."

On the other hand, you could take cuttings from many of the very same annuals, root them and avoid soil-born critters, at least, and probably any foliage based ones as well. Annuals with square stems and well those with leaves attached at points exactly opposite each other will root the easiest. Remove a bottom set of leaves and root in water or a damp sand-soil mix.

Of course, it simply goes without saying that you need a set of lights under which to grow your transported plants as well as existing indoor ones. It is a must for their health and optimal performance. The prospect of nine months of indoor gardening should be all the inducement you need to set something up to supplement the meager natural light we and your plants have to endure all winter. You can buy a fancy setup or use a simple shop fixture with a couple of fluorescent bulbs (one cool white and one warm white).

Next, Alaska perennials don't generally do well if you try to take them indoors. However, now is the time to start collecting and planting seeds. They are ripe when pods naturally open and usually when the seeds are black or dark brown. Try planting some in flats now and leaving them in the garden. This emulates their falling on the ground as they would normally. If you are lucky, seedlings will appear next spring.

Finally, the end really is near. So make sure you enjoy what growing season we have left. Harvest. Plant perennials, trees and shrubs and play on the lawn.

Jeff's Alaska Garden Calendar for the Week of August 22

Plastic pot recycling day: Saturday 11 a.m.-5 p.m.: Join Alaskans For Litter Prevention and Recycling and Alaska Botanical Garden to recycle types 2, 5, and 7 plastic pots. Please do not dump pots at the garden -- this event is one day only.

Harvest: Come on. Don't waste food. Drop off excess at a Food Bank, Beans Cafe, Alaska Mill and Feed or give it to someone who will use it. Alaska gardeners don't waste food.

Lawns: Fall is a great time to aerate. Do not fertilize with chemicals from here on in. Organics only.

This column just won the silver award for writing from the Garden Writers of America. Contact Jeff at

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