During the cold months, gardening moves indoors. Plants may become a big part of your holiday decoration plans but be careful not to let them dry out in heated indoor air. You can harvest all winter if you have planned ahead and have grow-lights for your indoor herbs and even lettuce.
Look for drying and browning of edges of houseplant leaves that can indicate too little humidity. If plants are suffering in dry, heated indoor air, group pots together to increase humidity, set pots on a tray of pebbles filled to half their depth with water, or set up a humidifier nearby.
The leaves of indoor plants get dusty, which can interfere with photosynthesis and transpiration, and provide insects a place to hide. Give smaller plants a rinse with the sprayer at the kitchen sink. Larger plants can be set in the shower. The leaves of large-foliaged plants can be wiped off individually with a soft cloth dipped in a solution of a few drops of mild dish detergent in a quart of tepid water, then rinsed with clear water. Be sure to wash off both sides of the leaves.
Poinsettias do best in a sunny window with an indoor temperature of 60 to 70 degrees. Avoid temperature fluctuations and areas where there are warm or cold drafts. Don’t fertilize the poinsettia when the plant is in bloom. One of the biggest mistakes we can make with poinsettias is overwatering. They are prone to root rot if the pot sits in saucer-full of water or if water is caught by the colorful foil.
Inspect bulbs you have stored in the basement. Remove any that show signs of rotting and mold growth. If the storage medium is dry, lightly moisten it with a spray bottle filled with warm water. You can still plant bulbs for daffodils, crocus and other early spring blooming flowers anytime the soil can be worked this month.
If the short, dark days of winter cause your indoor herbs to suffer, set up fluorescent grow lights or garden by a south-facing window to keep herbs and lettuces as vigorous as possible for winter harvesting.
Check stored vegetables, tubers, and bulbs; remove any spoiled ones immediately.
Shrubs growing near a building can suffer broken branches when a load of snow slides off the roof onto plantings below. The best way to protect vulnerable plants from damage is to erect wooden teepees over them as shields. If you are handy, you can build your own out of plywood.
Plants that need some protection from the cold may benefit from being wrapped in burlap or a covering designed for plant protection. Be sure to remove the covering on warmer days so the plant can breathe and take advantage of the sun.
Sunscald and frost cracking can damage the bark of newly planted or thin barked trees, such as maples and fruit trees. The south or southwest sides of the trunk are most susceptible to the temperature fluctuations that cause the damage. To protect trees, cover trunks with light-colored tree wrap tape or white plastic spirals. Be sure to remove the coverings in the spring.
Try to keep roses and other half-hardy perennials covered with snow—it’s the perfect insulator against cold.
When you trim branches from holly, boxwood, false cypress, juniper, and balsam fir for holiday decorating, be sure to remove no more than about five percent of the branches from any one plant. Cut back to a lower branch union so you don’t leave a stub, and make cuts so that the natural form of the plant is retained.
Do not try to remove wet heavy snow from evergreens; you could do more harm than good. Evergreen limbs remain supple through winter and will bend under the weight, but hopefully will not crack.
Make sure the root ball of your living Christmas tree stays moist (some folks use ice cubes), but don’t leave it indoors for more than a week, then plant it in the hole you dug last month. Make sure while it is indoors to keep it away from heat vents or fireplaces. The hot dry air will dry it out faster and may keep it from thriving after it is planted outdoors. Do the same for a fresh cut tree to keep it fresh longer.
Before the ground freezes hard, set up markers along the edges of lawns and gardens to serve as guides and prevent damage when plowing and snowblowing. Erect screens of burlap if necessary to protect plants, especially evergreens, from forceful blasts of snow from the snowblower.
Avoid salt and de-icers for your steps, walks and driveway. Use sand or a balanced fertilizer instead when possible since salt is harmful to plants and turf.