Your prime concern, after choosing high quality seeds, is the soil. Use the best soil you can get. Scrimping on the soil doesn’t pay off in the long run. If you use non-sterilized soil you will almost certainly find parasites in it, probably after it is too late to transplant your marijuana. You can find excellent soil for sale at your local plant shop or nursery, K-Mart, Wal-Mart, and even some grocery stores. The soil you use should have these properties for the best possible results:
1. It should drain well. That is, it should have some sand in it and also some sponge rock or pearlite.
2. The pH should be between 6.5 and 7.5 since marijuana does not do well in acidic soil. High acidity in soil encourages the plant to be predominantly male, an undesirable trait.
3. The soil should also contain humus for retaining moisture and nutrients.
If you want to make your own soil mixture, you can use this recipe: Mix two parts moss with one part sand and one part pearlite or sponge rock to each four gallons of soil. Test your soil for pH with litmus paper or with a soil testing kit available at most plant stores. To raise the pH of the soil, add ½ lb. lime to 1 cubic foot of soil to raise the pH one point. If you absolutely insist on using dirt you dug up from your driveway, you must sterilize it by baking it in your oven for about an hour at 250 degrees. Be sure to moisten it thoroughly first and also prepare yourself for a rapid evacuation of your kitchen because that hot soil is going to stink. Now add to the mixture about one tablespoon of fertilizer (like Rapid-Gro) per gallon of soil and blend it in thoroughly. Better yet, just skip the whole process and spend a couple bucks on some soil.