First, I just wanted to let you know there are still some seats available for our “Spring Into Gardening Event”. It is on Saturday, Feb. 17, from 8:30 a.m. to noon. You can register on-line at www.web.extension.illinois.edu/ccdms, or you can call the University of Illinois Extension office at 217-345-7034 for assistance. Looking forward to seeing all of you again this year! Well, we are into the first part of February already, and winter seems to be going by quickly. I wrote this article before the Groundhog’s prediction, but most likely we are in for six more weeks of winter.
Q: Can you address the question of fertilizing houseplants? Should I fertilize year-round? If so, how often?
A: This question could have many answers, to say the least. Fertilizing houseplants is like watering houseplants. There is no general rule, except that the average houseplant is more on danger of getting too much, than getting too little. One course of action is to watch each plant for changes that signal its needs. Is it trying to put out new leaves? Do you see a suggestion of flower buds? Alternatively, is it just sitting there looking green? Plants are hungrier when they are in active growth or preparing to bloom than they are when they are resting during the winter months. Most houseplants do not need to be fertilized more than once every 1 – 3 months, between March and September. During the short days of winter, plants experience a rest period and usually need very little or no additional fertilizer. Most foliage houseplants do keep slowly making leaves and getting larger, but very little fertilizer is required to maintain this status quo.
Q: The tops of my houseplants pots are coated with a white crust, “Is this harmful”?
A: What you are seeing is a buildup of salts from chemical fertilizers, and often indicates over fertilization. The easiest way to dissolve salts from containers is to remove the residue and soil from the top of the pot, followed by a flush of distilled water or rainwater equal to twice the volume of the pot or container.
Q: Can I use soil from my garden in the pots of my houseplants?
A: As a rule, garden soil is not practical for houseplants or seedlings because it contains insects and the pathogens that afflict plants. If you do not want to buy a commercial potting mix, which is already free of these problems, you can try pasteurizing your garden soil. To do this, sift the garden soil through your fingers to remove pebbles and twigs. Then pour it into a deep baking pan and add enough water to wet it completely. Stir thoroughly so the water is uniformly distributed. Pre-heat an oven to 180 degrees and heat the soil mixture for about 45 minutes. The procedure will kill soil-borne insects and diseases. After the soil cools, it can be prepared for houseplants: combine equal parts of soil, sand, or perlite, and composted leaf mold or peat moss.
If you have other questions about your garden or landscape, feel free to contact a Master Gardener volunteer at the University of Illinois Extension office in Charleston at 217-345-7034. You can also check out the many horticulture webpages at the U of I Extension’s website by visiting http://web.extension.illinois.edu/ccdms/ . And be sure to like the Master Gardeners’ Facebook page, at www.facebook.com/ColesCountyMasterGardeners.