The underlying philosophy of healthy gardening is to learn how to work with nature, not against it. The same applies to pest and disease control. It is better to prevent pest problems than to fight them, and if one must eradicate pests, it is better to use relatively benign inputs than to use a host of toxic chemicals.
Pesticides should be a last resort, not the first line of defense. If a certain chemical pesticide is routinely applied, subsequent generations of insects gradually build up a resistance to that chemical, so new and often more toxic chemicals need to be applied, creating a vicious cycle of chemical warfare with many potential negative side effects for consumers and the environment.
In my gardening classes, I recommend the following progression of steps for integrated pest management. The more thoroughly the first steps are implemented, the more unlikely the need for the more drastic steps:
- Follow cleanliness protocols.
- Strengthen plants’ natural resistance to pests and diseases.
- Use organic insecticidal sprays.
- Introduce beneficial insects and micro-organisms.
- Use registered chemical insecticides.
The more thoroughly the first steps are implemented, the more unlikely the need for the more drastic steps. The first and foremost mantra of integrated pest management is, “Start clean and keep it clean!” Once a set of cleanliness protocols are established, they soon become good habits that require little additional effort or forethought.
The minor inconvenience of following cleanliness protocols is nothing compared with the time, hassle and expense of continually battling pest problems. Here are some rules that should be followed religiously until they become good habits.
Never Bring in Outdoor Plants
However tempting, if you try to save a favorite plant by bringing it indoors, you will bring in every type of outdoor insect with it. Once the insects get established in your indoor garden or greenhouse, they will have the perfect environment to thrive, breed and overwinter, feeding on not only your favorite plant, but also all of the plants around it.
Change Your Clothes
Putting on comfortable, freshly laundered “gardening clothes” before entering the growroom is a good habit to get into. Street clothes are a potential vector for contamination, especially if you have been working outdoors or around other plants. After working in the indoor garden, it is fine to wear the same clothing in your outdoor garden, but never the other way around.
Wear Clean Shoes
If possible, have a designated pair of clean slippers or shoes waiting at the door of your growing area. Outdoor shoes can track in dirt and carry a plethora of potential pests and pathogens, so leave your street shoes at the door. If you must wear street shoes into the growroom, try putting a shallow pan of 10% bleach water at the entrance, and step in it every time you enter the room. Make sure your guests do the same.
Wash Your Hands
If you smoke cigarettes, it is possible to transmit tobacco mosaic virus and other diseases to your plants when you handle them, so get into the habit of washing up before entering the room. Pets are also a vector of contamination, especially for transmitting mites. Always try to keep animals out of your growing area, and if you pet one, make sure you wash your hands before working in the garden. Better yet, wash your hands every time you enter the garden so you don’t have to think twice, and keep a bottle of hand sanitizer at the door.
Sanitize Tools in Rubbing Alcohol
Contaminated scissors and garden tools can also spread viruses and diseases from plant to plant. If you have an outdoor garden and an indoor garden, keep two separate sets of tools. It is also a good idea to keep a bottle of rubbing alcohol in your growing area so you can dip and clean your tools after every use.
Use Bug Barriers
Sticky traps are a good first line of defense for monitoring and controlling common insect pests. Yellow sticky traps attract flying insects such as aphids, whiteflies and fungus gnats. Blue sticky traps are best for monitoring thrips. If an insect problem arises, early detection is the key, so hang sticky traps in an easy-to-see location near the plant canopy.
A good bug barrier for crawling insects is Tanglefoot, the sticky stuff on sticky traps. Tanglefoot can be spread around the lips of pots, on colored paper strips or across any path a crawling insect might traverse. If you use pots with soilless mix, a top layer of diatomaceous earth can also discourage crawling insects. Its microscopic, sharp edges cut insects as they crawl across it or try to burrow through it.
Use Insect Screens on Vents
Any windows, vents or other openings to outside air should be covered with insect screens. Although any type of screen is helpful, the best insect screens are those rated for thrips. Thrips are extremely small, so if you can block them, you can block any insect. Just remember, the finer the screen mesh, the more resistant it is to airflow. If you are planning to use thrip screens, make sure you install large-enough exhaust fans to handle the restricted airflow.
Include Positive-pressure Entryways
Although it’s a bit extreme, a positive-pressure entryway to the greenhouse or growroom adds an additional layer of protection from the outside air. Enough filtered air is forced into the entry room so that when the door to the outside is opened, air is pushed out, not sucked in. This extra level of protection is only required if you want to produce “certified” disease-free plants for export, or if you are constructing a clean room for tissue culture micro-propagation.
Clean Up Regularly
When you leave the growing area, always take the trash out with you. Dead or diseased leaves, used paper towels and other trash can form breeding grounds for pests and diseases. Use small litter bags that can be removed immediately, not larger bags that accumulate trash. Also, clean up spills right away, and set up a regular mopping and cleaning schedule that you follow like clockwork.
Once you establish a maintenance schedule for your plants and your growroom, always follow it, whether it needs it or not. A sparkling-clean growroom is a pleasure to work in, and in the long run, your plants will thank you for it!