2008-11-13 / Editorial

The Island Garden

Did you know that the most common way to kill indoor plants is to overwater them? Or that indoor plants hate New England winters? Or that you need to repot your plants regularly or they become root bound, which slows their growth?

By Roger Marshall By Roger Marshall If you didn't, you probably buy a plant at the store, then take it home and kill it. Not that you beat it with a hammer, more that you kill it with kindness.

A few simple tricks can help your plants survive. First, use the one finger approach. Stick your finger into the dirt once a week during winter. If the dirt is moist do not water. If it is dry, and it most likely will be, water your plant. Do not add any fertilizer until the days start to lengthen next spring. Just use common old tap water that you let sit overnight. Letting it sit helps to get rid of some of the chlorine it the water that plants hate. If you really want to give your plant a treat, stick a rain barrel under your downspout and use ordinary rainwater, but make sure it is room temperature before you put it on your plants.

That is all you need do for the winter. Nothing else, no pruning, no repotting, no heating. Just let the plant sit in a moderately sunny window and water whenever your finger test says it's dry. When you set the plant in the window, make sure it is 10- to 15- inches back from the window during winter. That is because cold air from the window falls downwards and you don't want your plant to be in that torrent of cold air. After all you wouldn't sit there, so why put your plant there. Also, don't put your plant near the heating vent. Hot air from the vent will dry out your plant.

When humidity levels get really low, as they do in the middle of winter, or if you have a wood burning stove, group your plants together so that they can all benefit from the humidity given off by each other. Experts call this creating a micro-climate. Or you can collect a bunch of similarly sized small pebbles from the beach and put them in a tray. Put water into the tray until it is about half way up the pebbles and set your plant on the pebbles. Do not set the plant in the water. Most plants don't like "wet feet" - that is, wet roots, but they do like the additional humidity from sitting atop a tray of pebbles.

This time of year

If you are bringing the plant in from outdoors, spray it with insecticidal soap now and in 10 days time to kill off any insects. If you don't do this, any insects may hatch when your indoor heating comes on and may spread to other plants. Stop fertilizing your plants now and bring them in out of the cold. Wash your plants well with a garden hose before bringing them indoors and check under the rims of your plant pots for slugs, snails sowbugs and other non-desirables.

Leave your indoor plants for a week to 10 days and check carefully for insects. It is not unusual if you have not sprayed to find caterpillars munching on leaves, or other insects enjoying a world free of predators.


Around April next year, you can start to fertilize your plants. When beginning a fertilizer program, start by adding a teaspoon of fertilizer to the water, then increase it gradually to the desired strength. Unlike you, who may need your cup of coffee in the morning, plants can't immediately use the boost they get from a big dose of fertilizer. If you start small, you get the plant hooked, and then increase the dosage. But you only need fertilize with a recommended dose once a month. I prefer to fertilize using about half of the dose every week or two rather than hitting them with a big dose of fertilizer.

What type of fertilizer should you use? That will depend on the plant, but you can't go far wrong making your own compost or manure tea rather than using chemical fertilizers.


Spring is also the time to repot your plants. It's easy to do, and is best done outside on the lawn or in a growing bed because you will make a mess. Put your hand over the potting soil around the plant to help hold the dirt in place. Invert the plant (if it is small) and check to see what the roots are like. If they are growing around the bottom of the pot, you need to repot. You'll need a larger pot with an inch or two of potting soil in it. If the plant roots are wound around the bottom of the old pot, tease them out so that they are straight. Don't worry of you break a few. In fact, you might want to prune a few off anyway. This is called root pruning. When the roots are sorted out, put the plant into the new pot and pack potting soil around it. Water it well. The potting soil will probably sink down around the edges so ne prepared to top it up again. That's it, plant repotted.


To make manure or compost tea, simply buy or make a cotton or cheesecloth bag, half fill it with manure or well-rotted compost and put it in a bucket of water. Leave it for two or three days, then remove the bag and put its contents on your garden. Use the "tea" on your plants. They'll love you for it.

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