Sterilization of Soil
All soil should be sterilized before use. In large greenhouses this is usually done by steam, which is too costly for the small grower. But there are good sterilizing chemicals available.I like Fumi-Soil capsules. Place soil in a metal-lined bin, such as a clean garbage can, and add one capsule to each square foot of soil. If this is dry, moisten it a little. When the last layer of soil is placed, cover the container for 10 to 14 days. Then dump the soil out to aerate it before use. Follow package directions faithfully.
For soil in a bench, formaldehyde is a good sterilizer. Use one quart of 40 per cent formaldehyde to 12 gallons of water to cover about 4 square yards. Do not plant in the soil for about a week.
A few growers sterilize by the slow and rather clumsy method of baking soil in the oven for about 1 hour at 180 degrees F. This is not entirely reliable.
Storing Soil
If you must store potting soil in an unheated building, let it stand in a warm room at least 24 hours before use. Avoid fresh manure, it will burn tender plant roots.
POTS—SIZES AND KINDS
Regular clay pots are as deep as they are wide at the top. There are also three-quarter pots, called azalea pots, and bulb "pans." These are not really pans but simply pots which are about half as deep as they are wide. Pans are just right for rooting cuttings and forcing bulbs. The orchid pot has holes spaced all around the sides for extra drainage.Some gardeners prefer plastic pots. They come in various shapes and sizes and can be time-savers for an experienced person who understands watering and the needs of plants. The plastic pots are lightweight, attractive, easier to clean than clay pots, and more retentive of moisture.
Most commercial growers, nevertheless, still use clay pots for growing, reserving the plastics for shipping. They maintain that a clay pot is ideal because it is porous. Roots need to grow out and around the inside of the pot, and require water, nutrients, and air, which they receive more effectively in clay. Feel a clay pot filled with moistened soil and you will note that it is 10 to 15 degrees cooler than a plastic pot of soil. And that's a healthy condition for roots.
If you have old pots, scrub them well before use. I add 6 table spoons ful of Carco-X to the boiler of water in which I wash pots. This antiseptic, which contains some tar, removes soluble salts and algae, and is not hard on hands. Never store plastic pots outdoors, as sudden temperature changes often cause them to crack.
If you live in Arizona, New Mexico, Texas, or other areas where summer heat produces excessive evaporation, you may save work by using plastic pots.
However, crusts or chemical concentrates (resulting from fertilizing) may form and necessitate frequent repotting or scraping away from top soil.
How to Pot your Plants
Correct potting and timely transplanting mean extra profits. You'll save time and effort if you first assemble pots, drainage material (pottery chips), soil, and plants on your potting bench. Use only clean pots. If you have new clay pots, soak them in water for several hours prior to potting so they will not draw moisture from the soil. New plastic pots need no washing.
Save broken pots and use the pieces ("crocks") for drainage material.
Repotting
When repotting plants that have outgrown containers, shift them to pots one or at most two sizes larger. Place an arched piece of crock over the drainage hole. For a 4-inch pot, add about a % inch layer of gravel or tiny crock chips. For smaller pots, decrease the amount of drainage material; increase it for larger pots.
To remove a plant from a pot, turn it upside down. Rest it on your left hand, with your finger tips straddling the plant's stem and supporting the soil.
Use your right hand to hold the inverted pot steady. Rap the pot edge against a table or bench and let the plant slip out of the pot. Before repotting, remove old drainage material which may cling to the bottom of the root ball. If this seems hard, with your hands or a stick remove some of the old soil before replanting.
Put a small amount of soil above the drainage material in the new pot, place the plant, and fill in the space around the root ball with fresh soil.
Leave at least ¼ inch of space between pot rim and soil level in small pots, up to 1 inch of space in larger pots, so plants can receive enough water at one time. Finish by rapping the bottom of the pot on the bench to firm the soil. If you are transplanting large plants, mature amaryllis or philodendron, center the plant above the drainage material, fill in the sides with soil, and tamp it as you fill. Do this with your fingers or a rounded stick.
