What is sterile soil? Why would a plant need sterile soil over a soil that had compost?

Question

I got directions on a new plant to plant it in sterile soil. Is soil really ever sterile? Wouldn't that mean there were no nutrients in the soil? How does one sterilize soil? Boil it? Please enlighten me, thanks!

Answer 1

Sterile soil is necessary for propagating cuttings and is good for germinating seeds. Cuttings are exceptionally vulnerable to infection where a healthy plant would have no problems.

To sterilize soil at home simply bake it at 300 for two hours. It must remain moist during the baking time so keep it in an enclosed container. Try a poultry roasting bag and wet the soil with distilled or bottled water.

Keep it moist for several reasons: control odors, and avoids breaking down the mineral content.

If germinating fern spores or rooting cutting pour well boiled water (at least 5 minutes) over pots and equipment.

http://books.google.com/books?id=4u3A3kr...

Chemical sterilization uses extremely hazardous materials so is for commercial settings only.

http://www.madsci.org/posts/archives/200...

If your plant is not native using your garden soil may expose it to microbes it has no defenses against. However all plants are adapted to their own habitat and a range of beneficial bacteria and mycorrhyzae so your plant will soon acquire them from air borne sources. Potting soil is often sold pre-inoculated with beneficial microbes to give your plant a head start.

Answer 2

sterile, here, refers to absence of disease germs/pests/weeds/spores, etc. the soil may have been chemically treated to prevent any unwanted growth or plant diseases. that does not mean that nutrients are absent - it may still be perfectly rich.

compost is made organically [from plant & animal refuse] & has a high chance of having disease germs, worms, spores, etc. So if your plant is prone to or highly susceptible to disease germs, then a sterile soil may be recommended.

you can even sterilize the soil yourself by adding/spraying pesticides & fungicides to the soil & sometimes exposing it to sunlight.

hope this helps