Overwintering Annuals

I trust everyone had a wonderful holiday and is looking forward to a stellar 2013 gardening season. I know I am.

by Jessica Walliser
It's possible to overwinter annual plants, such as geraniums or impatiens, indoors. Photo by Jessica Walliser (HobbyFarms.com)
Photo by Jessica Walliser
I like the challenge of overwintering annual plants, such as geraniums.

I trust everyone had a wonderful holiday and is looking forward to a stellar 2013 gardening season. I know I am. As the seed catalogs begin rolling in, I’ll be on the prowl for the newest flower and veggie introductions so I can give them a go in my own garden before reporting back to you on my successes and failures. In the meantime, I’ll focus on seeing my temporary “houseplants” through the winter.

To save money (and test my green thumb), I enjoy trying to overwinter some annuals each season. I often overwinter geraniums, impatiens, begonias and a few others. Here’s how to do it:

It’s quite easy to overwinter geraniums and impatiens indoors as long as you provide them with some basic needs. They should receive ample light; otherwise they will get very leggy and pale. A bright, sunny windowsill will suffice, but if you don’t have one of those, I suggest hanging a fluorescent shop light from hooks in the ceiling above them. The primary goal is not to produce blooms, so you don’t need to purchase any special grow-light bulbs. Just use fluorescent tubes. Keep the bulbs about 5 inches above the plant tops, and move them up if the plant grows. You’ll want to have them on for 12 to 15 hours per day.

Another good tip is to be careful to avoid overwatering. Geraniums and impatiens are very prone to fungal diseases, such as botrytis, if they are watered too often or if the foliage is frequently wet. Be sure the container has good drainage, and do not allow water to sit in the saucer beneath.

There is no need to fertilize through the winter because you don’t want to encourage too much active growth, but do begin to use a diluted kelp emulsion fertilizer when April arrives. You can do this every two to three weeks until the plants can be moved outdoors.

Pinching back the plants back might also be another necessity once or twice during the next few months. In order to keep the plants compact and bushy, use a pair of sharp, clean scissors to remove the terminal 2 inches from each stem. This will encourage a well branched plant that is less likely to become leggy and top heavy.

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As for my begonias, how I overwinter them depends on the type. I don’t bother overwintering wax begonias, as it isn’t really worth the effort, but if I grow Dragon Wing or Angel Wing begonias I follow the directions above. If they are tuberous begonias, I dig up the fleshy tuber, cut off all the foliage, brush off the soil, let them sit for a week in a cool, dry place and then store the tubers in a cardboard box filled with peat moss in the garage. Then I replant the tubers come May. 

For more information on overwintering garden plants, check out my post “Overwintering Container Plants.”

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