Soil Sterilization

What are the different ways to sterilize soil for seeds?

Steam, very hot water, and chemicals, such as tear gas (chloropicrin), methyl bromide and Vapam.

How does the gardener sterilize soil with steam?

Make a soil pile 12 ins. deep. Place 4 ins. agricultural tile 2 ft. apart in center of pile and running full length. Plug tile at one end. Insert steam pipe of hose in the other end. Cover entire pile with building paper or canvas. Inject steam for 2 hours; remove cloth; allow to cool. Remove tile, and continue the process. Steam sterilization makes structure better. Its effects are entirely beneficial. This is usually impractical for a gardener to do. Small quantities of soil for pot plants may be sterilized in a pressure cooker, without closing the steam valve.

What is an easy and efficient method of sterilizing soil for growing seedlings in small greenhouse where steam is not used?

Boiling hot water should be poured over the soil and, in addition, the seeds should be dusted with Captan, Thiram Terrachlor (PCNB) or similar compounds.

What is Larvacide?

It is a gas which is packaged in bottles or cylinders as a liquid (chloropicrin, or tear gas) and is applied to the soil with a special applicator. The soil should be 60 degrees F. or warmer, and medium moist. Three c.c of liquid (a small teaspoonful) is injected about 3 to 6 ins. deep, spaced 10 ins. each way. A heavy watering is applied immediately. Follow with two other applications on successive days. The treatment controls soil diseases, insects, and weeds.

What chemicals can be used to sterilize small amounts of soil?

The most practical is Vapam, which requires no special equipment. Follow the simple directions.

How do you sterilize soil with formaldehyde?

Where steam is not available, formaldehyde may be used. Use commercial formalin – 1 gal. to 50 gals. of water. One gal. of the solution is used to 1 sq. ft. of soil 6 ins. deep. Pour solution on, cover for 24 hours, then uncover and permit to dry for 2 weeks before using.

How do you sterilize soil for potted plants?

Use steam, hot water, or chemicals. A pressure cooker may be used satisfactorily.

How is sand, used as a rooting medium, best sterilized?

If small quantities are wanted, place sand in shallow flat or box, and pour boiling water through it.

How do you sterilize soil in a perennial bed?

This cannot be done satisfactorily unless chemicals are used – formaldehyde, chloropicrin, Vapam or mercuric compounds. Beds must be free of plants before chemicals are applied.