fter the initial set up (and like any outdoor garden) there is the regular and on-going maintenance needed to ensure your garden's health. A careful eye must be kept on plants for any signs of irregularities or deficiencies. Poor leaf and bud formation or discolouration, stunted growth or blemishes could all be a signal of trouble. Any of these indicators could mean there are nutrient toxicities or there may be predators present. A careful inspection of plants will determine if you are dealing with a pest problem.

In hydroponic/organic gardens and all organically certified gardens, chemical pesticides are not permitted. Though deemed safe for human consumption by national agriculture standards, chemical pesticides remain on leaves, stems and fruit of plants after harvest. Thoroughly washing produce is believed to eliminate most of the contamination, however, a little residue may remain. Some chemical pesticides are systemic, remaining in the plant for the duration of its life and transferring to the fruit. No one is really sure what effect the long-term accumulation of these chemicals in the human body is causing. The bottom line is that pesticides are poisons designed to kill living organisms! They have been implicated in several types of cancer, birth defects, nerve damage and genetic mutations. Keeping these chemicals out of your gardens will help minimize the risks.

Fortunately hydroponically grown plants have a tendency to be strong and healthy, leaving them less susceptible to attacks by insects. Quick and aggressive, biologically safe intervention measures, used at the first sign of pest damage, usually eliminate further infestation.
In the past we have discussed biological control agents or beneficial insects and their advantages. They are an ideal preventative against infestations and can be brought in at the first sighting of a destructive invader. There are many insects that feed on plants, and for every crop-damaging trespasser, there is a natural predator that is commercially harvested. Often pest control is integrative, employing biological controls with natural insecticides.
Over the past decade extensive research has been conducted in the search for effective, non-harmful organic pesticides. Most of the new organic insecticides are sprays and powders that work as a preventative or repellent; a deterrent to would-be attackers. Pests find the smell or taste offensive and stay away. Kelp-based foliar sprays are a very popular choice as they discourage predators while providing

trace minerals through the leaf surface. Organic larvacides have been developed and are widely used to eliminate the larva of obnoxious plant eaters before they hatch. Organic larvacide programs have been implemented in areas where the West Nile virus is a threat. Mosquito larva is commonly found in ecologically fragile areas where invasive, chemical pesticides could potentially destroy the environment. Organic interventions are believed to be less destructive to the atmosphere, and less of a threat to the ecosystem's delicate balance.
Commercial pesticides deemed organic are usually plant-based (botanical pesticides). The active agent may be pyrethrum, derived from chrysanthemum flowers, or ryania, which comes from the stems and roots of the tropical shrub Ryania speciosa.
Even if a product is considered organic, it is still a pesticide. It is important to be careful when using any pesticide, even organic pesticides. Just because a product is thought to be organic, does not mean that it is not toxic. Some organic pesticides are as toxic, or even more toxic, than many synthetic chemical pesticides. Organic pesticides have specific modes of action, just as synthetic pesticides do.
While some organic pesticides may be nontoxic or are only slightly toxic to people, they may be very toxic to other animals. For instance, the organic pesticide ryania is very toxic to fish. Also, some organic pesticides may be toxic to beneficial insects, such as honeybees, if they are combined with other materials, such as combining pyrethrins with rotenone.
The Neem tree is considered the most effective and environmentally friendly source of pest inhibitors. The juice of the raw neem leaf is the most potent, wide-spectrum pesticide known to man. Neem juice and oil contains more than 50 different pest-killing compounds, so even insects with immunity to some substances cannot build up enough resistance to all the compounds. The major by-product from processing neem is called "cake." Fields top-dressed with cake were found to be less affected by nematodes, snails,

and certain fungi. Later tests showed neem oil to be very effective on plant diseases like rust and powdery mildew. Neem cake was also found to be excellent fertilizer, outperforming farm manure and sewage sludge. Neem oil is sold in hydroponic and indoor gardening shops throughout North America.
Nicotine from tobacco is deadly for insects. It attacks the nervous systems in bugs. Combined with other ingredients in a solution, the nicotine from tobacco is safe for humans and works to eliminate many of the pests that may inhabit your garden. Nicotine bombs are used in commercial greenhouses but are quite volatile and pose major risks if used improperly. Nicotine bombs are only available to individuals who possess a pesticide license.
In the early stages of a bug infestation, homemade insecticidal soaps are an excellent and safe alternative to some of the commercial products. Onions, garlic, cayenne pepper, horseradish and other pungent spices are some common ingredients included in homemade soaps. The recipes below combine variations of these ingredients in a vegetable oil and detergent-based solution.
While these natural mixtures are biodegradable, use them sparingly, since they will kill the good bugs, such as spiders and ladybugs, along with the bad ones.
Oil sprays are contact pesticides and work by suffocation. Oil sprays can be used to control aphids, mealybugs, scale insects, mites and thrips. Vegetable oils and light mineral oils such as paraffin are permitted for use in certified organic farming. Petroleum oil also known as ‘White oil', ‘All seasons oil', ‘Pestoil' and ‘Bug oil' is not permitted for use in certified organic farming.
For soaps to qualify for an organic designation the detergent or dish soap used must be pure or organic. The detergent works as a contact insecticide and breaks down the insect's exoskeleton, causing it to dehydrate and die.
An effective bug repellent spray can be made by boiling the juices of various herbs and spices in a pot of water. Heating will release their sharp odours, and once cooled the mixture can be
44 Maximum Yield Indoor Gardening Canada January / February 2006
sprayed directly on the leaves of plants. Diluted citrus juice also has bug repelling properties.

For a spray that is helpful in combating aphids and other surface-dwelling pest, mix 1 cup of tobacco with 1 gallon/4.5 litres of hot water. Allow to stand for 24 hours. The mixture should be the colour of weak tea. If it's too dark simply add more water. Warning: Tobacco should not be used on tomatoes, peppers, eggplant or other members of the solanaceous family.

This recipe combines several ingredients for maximum effect against aphids, root borers and more persistent problems:
- 2 parts Neem oil
- 2 parts Liquid Detergent
- 5 parts Tobacco
Mix first 2 components, whisk until dirty white, add the rest, whisk until light brown, add 20 parts water and steep for 6-12 hours. Do not strain but pour directly into pot.

For very serious infestations, remove root ball from the soilless mix or other growing medium and soak in a solution of:
- 5 parts Neem oil
- 5 parts Liquid Detergent
Mix and whisk until dirty white, add 10 parts water and whisk. Dip the root ball and let soak for 1 hour, then repot in clean medium.
Surface-dwellers like aphids, caterpillars, mildew and molds live above ground and destroy the aerial parts of the plant. These organisms have fairly strong but less adaptive immune systems, so are easier to conquer. This general recipe will kill all but the hardiest pest.
- 2 parts garlic
- 2 parts onion
- 3 parts Tobacco
- 1 parts Pine oil (quite effective for aphids and white fly)
- 2 parts Liquid Detergent
Mix the last two together and add the rest. Add 30 parts water and steep for 4-6 hours. Strain and spray on to the plants.

Whitefly began showing resistance to synthetic insecticides in the 1980s. Sprays containing pyrethrum or neem give the best control for organic growers. Both the surface and the underside of the leaf need to be completely covered.
This eucalyptus oil or mullein (herb) recipe is also quite effective though perseverance is required. Spray every 3 to 5 days until the whiteflies have been eliminated.
- 1/2 gallon of water
- 1/4 teaspoon eucalyptus oil or mullein (from a drug store or scent shop)
- 1/2 teaspoon mild dishwashing liquid
- 1/2 tablespoon vegetable oil
Shake well to blend and keep shaking as you spray, so the solution stays mixed. Carefully coat all afflicted areas.

- 28 grams table salt
- 4.5 liters of water
Shake well and spray liberally over plant surface and underside of leaves, or
- Steep 2 cloves of crushed garlic in 1 litre of water for 24 hours
Strain. Do not dilute. Spray on plants no more than twice a week (also works on aphids and scale mites.)
Experiment by crushing a variety of pungent household herbs or adding a few drops of your favourite hot sauce to a litre of water and let steep overnight. Spray liberally on plants and growing surfaces. Most of the heavily scented herbs or hot pepper sauces commonly used in your kitchen will discourage insects from venturing anywhere near your garden. Used weekly as a preventative, these solutions should provide adequate protection for your plants.