I guess as things turn Octoberish it is time to declare the indoor gardening season formally open. Sure, there is some overlap with the end of the outdoor season (at least for the zealous outdoor gardener) as you can plant all the way through the first few snows if the ground is still thawed. Still, for most of us, gardening is over outside. It is time to move totally inside.
Let's start with your existing plants. The beginning of the summer would have been the time to start getting them into shape for the winter, but no one ever bothers. So now, you need to inspect your plants with a critical eye and get rid of the ones that are not going to make it. These include those infested with mealy bugs, covered with spider mites, exhibiting less than one-third of its normal load of leaves and those that are already dead. Come on, you don't need my help here.
Next, trim, prune and clean those plants that will perform this winter. These would include any of the pelargoniums (aka geraniums), fuchsia, coleus, impatiens and fibrous begonias rescued from the frosts. They will all perform well in the winter. The pelargoniums, coleus and fuchsia will probably bloom on their own under natural light if kept cool. The fibrous begonias and impatiens will need a turn under lights to flower.
You may be able to root the trimmings from these plants. Remember, any annual with square stems will root easily and grow new plants from cuttings. Roots appear from the stem where leaves were, so pull off the bottom set of leaves, make sure there is at least one additional set still on the stem and put these cuttings into damp sand to root. Let the pelargoniums callous over a couple of days first.
The above plants were probably put into pots with new soil. What about your existing plants? Do any of them need to be repotted? Are their roots and shoots coming out of the pots? Are any of your plants in soil that has turned to "concrete"? Now is the time to get some great soil, full of compost and organics, and repot things. They will surely thank you during the winter months. Doing it now means you can still take advantage of above freezing days and repot outside where making a mess isn't a problem.
When you repot, not only do you want the very best compost-filled soil, you also want to use the right-size container, and it must have drainage. Containers should be at least 3 inches more in diameter than the previous container. It must contain at least one drainage hole. Do not put anything in the bottom to help with drainage. This area is for roots, not pebbles.
How about uninvited guests? Check yours. Did you bring in aphids when you moved plants indoors (or did they just sneak in without your help)? When the heat goes on in Alaska, spider mites appear at the axils of stem and leaves and branches and leaves turn yellow and drop off. White, cottony mealy bugs appear at these axils as well and suck the sap from plants. Neem oil or neem oil products are the defense of first choice. And while treating plants, isolate them from the rest of your collection.
You may already harbor fungus gnats that fly from the soil. This is a sign the soil is too damp on the surface. Let it dry out a bit more between watering and make newspaper coverings for the soil so the adults can't lay their eggs on the soil surface.
And, finally, just because it is my job, though annoying it is: lights. Get some. You need them and so do your plants. What are you waiting for? The indoor growing season has begun.
Jeffs Alaska Garden Calendar
Driveways: It is time to mark yours so the snowplow or shoveler knows where the pavement ends.
Outdoor containers: If yours are made of clay, they may freeze and crack this winter. Either move them inside or turn them upside down so they don't fill with water.
Potatoes and Brussels sprouts: Time to harvest if you have not already. They need a few frosts to increase sugars.
Alaska Botanical Garden Workshops: Two great workshops: garlic (Saturday, Sept. 26, if space is available) and potato harvesting (Wednesday, Sept. 30, repeats Saturday, Oct. 3). There is a charge and you need to reserve space. Visit alaskabg.org for times and more information.