Home & Garden: Garden indoors as you wait for spring to arrive
March in North Dakota is still winter and so it is not time yet for outdoor gardening. However, the longer days and brighter light that is beginning inspires our indoor plants to put on growth. This is an opportune time to give extra care to these house-plants.
Take a good look at each plant. Is it dusty and in need of a little cleaning to allow more light to reach the foliage? Is there any sign of insect pests like mealybugs, spider mites, aphids or scale? Or is there indication of disease caused by overwatering? Do smaller leaves hint that the plant is not getting enough light or whitening of the leaves mean that it is in too much sunlight? Are there signs that the plant needs to be repotted?
Houseplants could have a good shower about once a month. Put them in a laundry tub or a shower and spray or sponge on a mixture of ½ teaspoon liquid dish soap per quart of lukewarm water. Rinse with tepid water. Trim off brown edges and remove dead leaves.
Signs of insect infection include fine webbing from spider mites, sticky residue from aphids or the appearance of white, gray or brown mealybugs or scale on the stems or leaves. The first step in control is to wash with the dishwashing solution.
Next spray with insecticidal soap such as Safers or Schultz for indoor plants. These are made of potassium salts of fatty acids and are effective against a broad spectrum of plant pests. An insecticide with pyrethrum like Schultz or Spectracide can control most pests except fungus gnats and springtails. If the infection is too bad it is best to discard the plant.
Next to light, water is the most important factor in houseplant success. More houseplants are killed from overwatering than from anything else. Pick a day a week to check your pots. Feel the top of the soil and if it is dry then water. Large pots may still be moist lower, so poke your finger in up to the first knuckle to assess the dryness. Water all the way around and in the middle until water puddles in the tray below. One of the worst things is to let plants sit in the water in the tray, so be sure to dump it out after letting the pot drain for a while.
It is best to use room temperature water for tropical plants, which most houseplants are. Chlorine in the water is not a problem, although fluoride may be. Avoid softened water, but if that is not possible water heavily and allow the excess to flow through to the sink. Melted snow, rainwater and water from the dehumidifier are all fine. With our alkaline water, lime build up happens, but it is harmless to most plants except azaleas.
Natural sunlight goes from more than 14 hours in spring and summer to a low of nine hours in winter. This may mean you will have to move plants to different locations during the year. In winter you might have to move plants away from cold windows and in summer you may need to protect them from too much sun. At about 8 feet from a window 75 percent of the light intensity is lost.
It is unnecessary to fertilize houseplants in winter as most plants except African violets are resting. Once they become active in late spring, it is time to start fertilizing.
To avoid burning, use half the recommended amount and apply it only when the soil is moist.
Eventually, plants become root-bound and spring is the best time to remedy this. Water the plant well the day before repotting to avoid breaking dry roots. Use a pot that is the next size up, not one that is much larger. Be sure the pot is sterile and has a drainage hole. Do not put rocks in the bottom. Use a clay pot shard or a piece of screen to keep the soil in. Select a commercial soil-less media appropriate for the type of plant you are repotting and make sure it is moistened. Fill and poke in around the sides to get rid of air pockets and leave enough room at the top (about ½ inch) for a water reservoir. Water thoroughly and keep the plant in a warm room out of direct sunlight for a few days.