Sunday, October 17, 2010
Wintering Herbs Indoors (part 2 of 2)
Yesterday I began a presentation on what to do when winter arrives and you want your plants inside with you. Previously I discussed what to bring in, what not to bring in and how it is done. Today I am continuing with making the plants comfortable and how to treat them while indoors.
At this time of year there is still summery weather and frost is mild if at all, so rather than bring the plants in too soon, I leave them outside. If a cold night is forecast, I bring them in over night, and then take them back out in the morning, much like I would to get greenhouse plants ready to be out in the spring. This reverse hardening off, keeps the plants growing, but helps them realize there is change ahead.
As I said I move them closer and closer to the house as the weeks progress, sheltering them under trees or up against the siding so they can absorb the heat from the day into the night. I also place them in shady areas away from direct sun so they becomes used to the lower light levels. Once the days stay almost as cold as the nights, then they will stay in permanently.
Cut Them Back
Once your plants are ready to move indoors, it helps to cut them back slightly (by as much as a quarter depending on the plant.) Cutting them back stimulates new growth that will adjust to indoor conditions. In many cases the older foliage will drop off when the plant comes inside.
Watch for insects
Whiteflies, spider mites and aphids are three main pests you can bring in with the plants. You might want to go as far as examining your plants with a magnifying glass, checking for insects and eggs. One of the last steps I take before moving a plant inside permanently is to give it a wash. Using room temperature water, give them and overall gentle washing that includes tops and bottoms of leaves. Mild dish soap can be used, but is not needed, the washing itself dislodges the little creatures rather well.
Caring for the Plants Indoors
I arranged the pots in the sunniest windows of my home. In this case the picture window in the living room and the bedroom. I like the scented geraniums in the bedroom. There is nothing more intoxicating than being able to reach up a stroke the leaf of a scented geranium in the morning (relaxing too!) They get leggy in winter so the ability to spread along my headboard seems to appeal to them. Try to find a place with daytime temps near 70 degrees and evenings 55 to 60 degrees.
Humidity is required for indoor plants. If you begin to see brown leaf tips or edges, this is usually a sign of low humidity levels. To encourage enough humidity for your plants, sit them close together (they give off moisture) or set them on oversized trays of sand or pebbles. Fill the tray with water so the bottom of the pot sits above the water line. As the moisture evaporates it will fill the air around the plant with humidity. Misting has been used to assist with this issue, but for perfect protection you would need to mist almost constantly.
As light levels diminish with the approach of winter, the herbs seem to enter a holding pattern. They generally don’t appear to be growing. Water only when the soil becomes dry or nearly so. Sometimes I am lax with this, but the scented geraniums don’t mind. Rosemary will, however require constant humidity, so if you bring one indoors, place it on a tray of pebbles and keep a level of water in the tray at all times. This will protect it from the lack of humidity you have in a heated home in January and February.
Although the days begin to lengthen in late December, the herbs don’t seem to begin to grow until March. When I notice the new growth, I started fertilizing the plants occasionally with a dilute solution of soluble fertilizer. Don’t fertilize them until then.
Keep a close eye out for pests. They can lay dormant on the leaves of plants until reawakened by the heat and stress of the plant. Dish soap diluted in water and sprayed on plants can cut down the numbers, as well was washing off the plants leaves, but depending on infestation you may need to segregate an infected plant.
Another issue that can affect indoor plants is mildew. I have heard, but have not tried a mixture of baking soda and water used as a dip for stems can retard this once it starts. However, good air circulation should keep it from happening at all.
Providing adequate light in winter is always a problem. Grow lights are a good idea, but even with them plants can become leggy, so do not expect too much. I have used flood lights, fluorescent lights and even the new LED lights, but nothing can be a true substitute for sunlight. I have stopped using them because I just trim the branches back in the spring and let them do what they want in the winter if it keeps them growing.
Putting Them Outside Again
At the end of April, I began hardening off the herbs I have wintered over indoors. I place the pots close to the east side of the house where they get morning sun but are out of the wind. Once the nights are mild you can leave them out all night. This hardening off period can last a couple of weeks depending on the season. But once the fear of frost is past you can then plant them outside again to enjoy another season.
Once the herbs are outside you can relax, -- or maybe not!
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