Marijuana Horticulture: The Indoor/Outdoor Medical Grower's Bible

bacteria and other soil organisms.
    For best results keep sandy soil cool, retain moisture with mulch, and cultivate often, adding additional compost. Winter season cover crops will hold moisture and prevent runoff while retaining life in the soil.
    Loam soil has all the advantages of clay and sand; it holds moisture and water like clay but is quick to warm and has good drainage and a work-friendly structure like sand. It is the perfect growing medium.
    Most soils are a combination of sand and clay. Silty loam falls in between and feels almost greasy when rubbed in your hand, though it is less slippery than clay. The ultimate soil for growing plants is loam found in ancient river bottoms and lake beds where sedimentary soil builds up. It is dark, fertile, and crumbly in the hand.
    Forest soils vary greatly in pH and fertility. The needles and deadfall from the trees usually make the soil acidic.
    Most of the forests remaining in North America and Europe are on hillsides. Flat land is used for farming, recreation, and urban sprawl.
    Long-needle pines grow in poor soils such as those found in mountainous and tropical regions. They have deep roots to look for all the elements in the soil. When a layer of humus evolves, short-needle conifers dominate. The roots on these trees spread out on the surface to search for nourishment and bury roots to anchor it in place.

Once you have amended soil so it holds plenty of water and nutrients but still drains well, you can take it easy.
    Jungles are usually low-growing, hot, moist, and dense. The soil is shallow and alive. The hot weather makes all foliage that falls to the ground decompose quickly. Often nutrients are available to plants, but the soil does not have a chance to build density. Layers of tropical soils can be very thin. However, through much of Mexico and Central America volcanic eruptions brought much rock and minerals to the surface. Mountain valleys and lowlands are full of alluvial plains that are packed with nutrient-rich soil.
    Grasslands often have wonderful soil that recycles nutrients. Sunshine is likely to be good, but detection could be a problem in wide-open spaces. Plant in areas that are protected from wind and curious eyes.
    Mountain soils are often very rich in minerals but lack humus. Alpine valleys hold the best alluvial-plain soil that is the product of volcanic rock erosion. Hillsides are generally less fertile, and soil must be amended to grow a good crop.
    Bog soils are moist and spongy. Bogs are filled with vegetation and often have very rich soil. They present a perfect place to grow individual plants. Cut a square yard (90 cm 2 ) of moist sod from the ground, turn it over, and plant. Marsh ground supplies sufficient water on its own. Add a bit of time-release fertilizer during transplanting and another handful of “flowering” formula during a check-up in early August.

Turn over the top layer of grass to prepare moist soils for planting.
    Most often, it is easiest to change or amend native soil that will produce scrawny plants. You can grow in containers so you can control all factors, but just remember, containers require more maintenance. See “Terrace Growing” for more information.
    Amendments improve soil, root penetration, soil water retention, etc. See Chapter Ten, “Soil,” for a complete discussion of amendments.
    Maintain a compost pile. See “Compost” in Chapter Ten for more information.
    Worms work wonders with soil. Grow your own crop of worms in a worm bin. Worms grow and reproduce in layers of food scraps, soil, and manure. They produce worm castings, an excellent fertilizer/amendment or compost tea ingredient. For more information about worms, check out the classic book, Worms Eat My Garbage: How to Set Up & Maintain a Worm Composting System, by Mary Appelhof, Flower Press.
    Soil and water pH levels are exceptionally important. Cannabis does best with a soil pH of about 6.5. Soil pH is easy to change. See Chapter Ten for a complete discussion of pH.
    Lime amendments will raise pH and lower acidity, but too much lime can burn roots and make nutrients unavailable. If you need more than one full point of pH adjustment, check with local farmers, nurseries, or agricultural agencies for recommendations on lime application.
    Lime application differs based on soil type. Some guidelines are:
    35 pounds/300 square yards (16 kg/251 m 2 ) very sandy soil
    50 pounds/300 square yards (23 kg/251 m 2 ) sandy soil
    70 pounds 300