A reader with many years' experience of growing indoor citrus trees offers two more suggestions for keeping the trees happy, in addition to those I wrote about last month. His trees definitely are happy; they include a tangerine, grown from seed, which must be pruned regularly to keep it below the living room ceiling.
His citrus get a monthly bath, not a misting or a light shower, but a thorough wetting down, including the backs of the leaves. He considers the addition of horticultural soap to the water and a final spray with neem optional. The bath knocks back to zero the inevitable invasion of spider mites in dry indoor air. By the time that spider mite numbers have increased again, it is time for the next bath.
Second, his citrus trees all spend their summers outdoors, where no problems with pest insects appear. In other winters his trees have been attacked by various pests, but the bugs have been kept under control with horticultural soap or neem until the trees go back outdoors in summer. I am passing on his voice of experience to other readers with citrus trees.
Q: Do you stop fertilizing plants for the winter?
A: I do not. Some years back I experimented with less winter fertilizer vs. none at all. The verdict was in favor of giving plants some food even in the months when they are growing slowly. The plants looked better and stayed more healthy if not put on a diet of plain water.
Here is the system that I use, although other regimens may work just as well. For most of the year my indoor plants are watered all the time with a weak solution of water soluble fertilizer. Rather than try to calculate how often they should be fertilized and how often given plain water, I always mix a quarter teaspoon of fertilizer into a gallon of water.
During the winter months of short days and low sun — November, December, January — I give the plants plain water most of the time. I add fertilizer to the watering can just one day a week. That works out to something like a quarter as much fertilizer, depending on how thirsty a plant may be.
Q: Can I grow salad greens in the winter?
A: Absolutely. There are different ways, and the easiest is sprouting seeds. In a week or less the stem and seed leaves of salad greens can be ready to eat. Sprouting containers are available, but sprouts grow well in a quart jar with the lid replaced by plastic screen or mesh, which permits air circulation. The seeds should be rinsed with water every day as they grow.
Microgreens are my personal favorite. They grow in potting soil (ideally in seed starting soil) until the first true leaves form, or about two weeks. A little fertilizer will increase their size. Seeds can be planted in any container that is four inches deep and has drainage holes. The seeds should be scattered half an inch to an inch apart. Water them often enough to keep the soil damp, and give them lots of light. My seeds live under grow lights which are turned on 14 hours a day.
If you prefer high tech growing, you can invest in a hydroponic salad system, complete with LED grow lights, automatic water circulation, and notification of the correct time to fertilize. These systems take up about as much counter space as a salad bowl.
Master gardener Molly Hackett, whose motto is “Never trust a gardener with clean fingernails,” welcomes your questions. Send them to 1384 Meridian Road, Victor, MT 59875; call 961-4614; or email email@example.com. Please include a garden-related subject line in emails. Hackett writes a twice-monthly Dirty Fingernails opinion piece for the Missoulian.