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

by installing bat houses. Resident bats will eat moths and decrease the number of chewing caterpillars. Birds will eat caterpillars too, as well as aphids and other insects. Attract birds with suet, bird houses, baths, and feeders but cover tender seedlings and clones with wire or nylon mesh to protect from birds, too! Ladybugs and Praying Mantis are good options for insect control and can be purchased from nursery supply stores.
    Barns owls eat mice, gophers, and voles but are hard to come by in the city. If you are lucky enough to have them nearby, take advantage of their ability to eat plant pests. On the other hand, some rodents, like moles and shrews, help your garden by dining on slugs, insects, and larvae.
    Marigold cultivars of the Tagetes erecta and T. patula species, will repel nematodes, also known as eelworms, from the soil for two to three years if they are planted in an infested area and then tilled under. Just planting them in an area doesn’t accomplishanything. Numerous tests indicate that they do not have an effect on insects above the ground.
Frogs and Toads

    Frogs and toads eat insects and slugs. The frogs will need a water source, while toads are more terrestrial. Large snakes in the garden will eat gophers, squirrels, and mice as well as the moles and shrews. Snakes can give you a good scare if you come across one unexpectedly! The snake will also want to eat your frog. Plan carefully before committing to any mini-predator solution to pest infestation.
Birds

    Although most birds are welcome guests in most gardens, there are some that can make quick work of tender seedlings or new clones.
    The most effective way to keep birds from freshly planted seed and transplants is to cover plants with plastic wire or plastic netting. When installing the netting, make sure it is securely fastened around the perimeter of plants so hungry birds do not get underneath.
Deer and Elk

    Deer and elk love newly formed growth on cannabis plants. In addition, they may destroy crops by trampling them. Elk are somewhat of a problem, and deer are a problem!
    A cage around plants is the best deterrent. But remember, the wire may be easy to spot if it is not discreet in color. Deer are repelled by the smell of blood and human hair. Place handfuls of dried blood meal in cloth sacks and dip in water to activate the smell. Hang sacks from a tree to discourage dogs and other predators from eating them.
    Handfuls of human hair can be placed in small cloth sacks and hung from a fence or tree branch as a deterrent. Do not use your own hair; it could turn into evidence for police! Scented soaps have repelled deer from some gardens. But if deer are very hungry, the smell of blood meal, human hair, scented soap, or anything else will not deter them.
    Always urinate in several locations around the perimeter of the garden so animals take your presence seriously. Some growers save urine all week and disperse it at regular visits to their patch.
    Deer easily bound over eight-foot (2.4 m) fences. A good deer fence is eight feet (2.4 m) tall with the top foot (30 cm) sloping outward, away from the garden at a 45 degree angle. Electric fences and large dogs are also excellent deterrents.
Gophers

Gopher Trap
    Pocket gophers are small burrowing rodents that eat plant roots and foliage. These herbivores find fleshy roots a real treat and occasionally attack cannabis. Should a family of gophers move into your area, get rid of them as soon as possible! Females can bear up to five litters of four to eight offspring a year. A family of gophers can clean out a large garden in a matter of weeks.
    The only sure way to get rid of gophers is by trapping. There are several gopher traps available, including ones that capture them alive. It will take some skill before you are regularly able to catch gophers with traps. You must avoid getting human scent on any part of the traps. If gophers sense the human odor, they will simply push soil over the trap to spring it or render it otherwise ineffective. Traps are put in gopher runways and so don’t need to be baited.
    A fence of poultry wire or 0.5-inch (1.5 cm) hardware cloth buried one foot (30 cm) deep and standing 3 feet (90 cm) above the ground will exclude gophers. Line planting holes with chicken wire before filling with soil. Driving metal sheets around the perimeter of planting holes will also prevent gopher damage.
Mice and Voles

    Mice and voles can chew bark from around the base of cannabis