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Indoor Plant Soil

Date: April 1989 (Revised April 1995)

Source: NDSU Extension Service Horticulturists

A soil or potting medium for indoor plants should be loose with good fertility. It should have many air spaces and crumble readily between your fingers when you handle it. It should not pack, even after extended use and watering.

An excellent soil medium for growing most indoor plants is:

2 to 3 parts good loam soil
1 part sand -- perlite can be substituted for sand
1 part peat moss

Add 2 ounces of 20 percent superphosphate and 4 ounces of a complete fertilizer, like 10-6-4 or 5-10-5, per bushel of soil.

Mix the soil medium and fertilizer well before using it.

This mixture should work well for growing most indoor plants, with the exception of perhaps cactus and African violets.

You can also buy prepared soil mixtures to pot indoor plants. Commercial soil mixtures have already been sterilized. If you mix your own soil, sterilize it before using it.

A simple way to sterilize a small amount of soil is to put it in the oven. Place the soil in a shallow pan or tray and put it in an oven at 250 degrees for about 1 hour. This same effect can be accomplished by using a microwave oven. Place dampened soil in an open quart-size Zip-lock bag and treat at full power for 2 to 2 1/2 minutes. Then seal the bag and allow to cool.

If you have further questions, please contact your county office of the NDSU Extension Service.


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