compost is not very practical to use in containers. It could also have unwanted pests. If using compost indoors, make sure it is wellrotted and screened.

A good compost pile includes manure-the older the better. Manure from horse stalls or cattle feedlots is mixed with straw or sawdust bedding. Sawdust uses available nitrogen and is also acidic and not recommended. Look for the oldest, and most-rotted manure. Well-rotted manure is less prone to have viable weed seeds and pests. Fresh nitrogen-packed grass clippings are one of my favorites to use in a compost pile. Put your hand down deep into a pile of grass clippings. The temperature one or two feet down in such a pile ranges from 120° to 180°F (49° to 82°C). Heat generated by chemical activity kills pests, breaks down the foliage, and liberates the nutrients.

Build compost piles high, and keep turning them. Good compost pile recipes include the addition of organic trace elements, enzymes, and the primary nutrients. The organic matter used should be ground up and in the form of shredded leaves and grass. Do not use large woody branches that could take years to decompose.

Before using compost indoors, pour it through 0.25-inch mesh hardware cloth (screen) to break up the humus before mixing with soil. Place a heavy-duty framed screen over a large garbage can or a wheelbarrow to catch the sifted compost. Return earthworms found on the screen to the medium and kill cutworms, Make sure all composts are well rotted and have cooled before mixing with indoor soil. For more information about com-

Used Soil

Let soil dry.

Screen to separate roots, stems, and foliage from the soil. Pack in plastic bags. Remove soil from properly. Dispose of discreetly.

posting, see Let It Rot!, Third Edition, by Stu Campbell, Storey Press, Prowal, VT.

Some growers mix up to 30 percent perlite into organic potting soil that contains lots of worm castings, Heavy worm castings compact soil and leave little space for air to surround roots. Adding perlite or similar amendments aerates the soil and improves drainage,

Growing Medium Disposal

Disposing of used growing medium can be as big a problem as finding the proper soil. Most soilless mixes and soils contain perlite, which leaves white telltale traces when dumped anywhere. Crow soil is also packed with incriminating cannabis roots. The plug was pulled on more than one grow-show because soil residuals were found in the back yard.

Diy soil is easier to work and transport. Press and rub dry soil through a 0.25 to 0.5-inch screen to remove roots, stems, and foliage. Screening also transforms the cast-container shape of the soil to an innocuous form. Once the roots are removed, dry, used soil can be bagged up or compacted. Place the dry soil in a trash compactor to make it smaller and more manageable. Do not throw the spent growing medium into your trash can. Remember, it is not a crime for law enforcement in America to dig through your garbage. In fact, picking through a suspected grower's garbage is a tactic often used by American authorities to secure a search warrant. Remove the depleted soil from the property. Take it to the dump or dispose of it in a very discreet locale. Never throw away the transporting bags with the used soil. Reuse the bags.

Used indoor growing mediums make excellent outdoor amendments when mixed with compost and garden soil. Do not reuse the depleted soil in outdoor pots. Many of the same problems that occur indoors will happen in outdoor pots.

Grow Medium Problems

These maladies are caused by growing medium problems but manifest as nutrient problems. The solution is found within the growing medium.

When water is abundant in the growing medium, roots easily absorb it. Roots use more energy to absorb more water as it becomes scarce.

CEC of popular growing mediums measured in Milli-Eq/100 grams

Compost 90

Sunshine Mix 90

Peat moss 80

Garden soil 70

Expanded clay 20

Vermiculite 20

Perlite 0

Rockwool 0

This chart shows different growing mediums' ability to hold positive charges that are ready for root uptake. Note the zero CEC of perlite and rockwool. Roots must be constantly bathed in nutrients. Other mediums do not provide a constant flow of nutrients and the CEC regulates the ability to hold a positive charge to make nutrients available for root uptake.

Finally, the point comes when the substrate retains more moisture than it surrenders, and the roots receive no water. A good growing medium readily yields its bank of stored water and nutrients. A poor medium does not pass enough nutrients to a plant's roots. The more easily cannabis absorbs nutrients, the higher the yield.

The cation-exchange-capacity (CEC) of a growing medium is its capacity to hold cations that are available for uptake by the roots. The CEC is the number of cation charges held in 3.5 ounces (100 gm) or 100 cc of soil and is measured in milli-Equivalents (mEq) or Centi-Moles/kg on a scale from 0-100. CEC of 0 means the substrate holds no available cations for roots. CEC of 100 means the medium always holds cations available for root uptake. Growing mediums that carry a negative electrical charge are the best.


Container preference is often a matter of convenience, cost, and availability. But the size, shape, and color of a container can affect the size and the health of a plant as well as the versatility of the garden. Containers come in all

Ceramic containers are durable but heavy.

Visible Signs of Grow Medium Stress

Dry, crispy, brittle leaves Patchy or inconsistent leaf color Yellow leaf edges that worsen Crispy, burnt leaf edges Chlorosis-yellowing between veins while veins remain green Irregular blotches on leaves Purple stems and leaf stems Leaf edges curl up or down Leaf tip curls down Super-soft pliable leaves Branch tips stop growing Leggy growth

Continue reading here: Soil Containers

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