USING PLANTS TO PROTECT OTHER PLANTS
Reproduced with thanks to the CANADIAN ORGANIC GROWERS and to the CITY OF TORONTO website
Protecting plants from unwanted insects by using other plants is the natural, chemical-free way to remove harmful insects from your garden. And you won't be eliminating all the beneficial bugs.
Research indicates that plants produce excessive foliage and can afford some pruning. Natural pruning by insects can improve yields and increase the vitamin content of fruit in certain plants.
A certain relationship exists between plants, and between insects and plants. Companion planting is the usual name given to the practice of planting according to these relationships, but actually four different practices are involved.
- Mixed: Planting several different plants together, as in nature, so that insects are confused by the multitude of "smells" and have more difficulty finding the plant they prefer to eat and lay their eggs on.
- Repellent: Certain plants such as marigolds, mints and garlic are offensive to some insects, and will deter them when planted near other plants.
- Companion: Combinations of plantings produce crops that grow better and are healthier because of their proximity.
- Trap: Lure plants are located near a plant you want protected. Insects attack the lure plants and can then be hand-picked and destroyed.
Helpful Herbs and Flowers
- Learn to identify insects and diseases so you'll be able to detect problems early.
- Encourage natural enemies such as toads, birds, ladybugs and praying mantis, who will eat harmful bugs.
- Rotate crops to avoid a build-up of pests in any one area.
When planning your next garden, experiment with these forms of natural plant protection. No doubt you will also come up with your own safe and effective combinations.
|Plant|| Companion|| Advantages|
|Basil ||Tomato ||Improves growth and flavour; repels flies and mosquitoes.|
|Dill ||Tomato|| Traps the tomato hornworm.|
|Garlic ||Roses, Raspberries|| Improves growth and health; deters Japanese beetle.|
|Lamb's Quarter|| Throughout garden,near corn.|| Trap for aphids.|
|Marigolds(smelly types like Mexican, African and French)|| Throughout garden.|| Discourages Mexican beetles, nematodes and other insects.|
|Mint ||Cabbage, Tomato|| Improves health, flavour; deters white cabbage moth, ants, aphids and flea beetles.|
|Nasturtium ||Radish, Cabbage,Cucurbits and under fruit trees.|| Trap for aphids. Deters squash bugs, whitefly, striped pumpkin beetles and Colorado potato bug. |
|Wormwood|| In perennial border.|| Deters small animals and flea beetle and slugs.|
Plants that naturally repel insects
|Pest|| Plant repellent|
| Ant || mint, tansy, pennyroyal|
|Aphids|| mint, garlic, chives, coriander, anise|
|Bean leaf beetle|| potato, onion, turnip |
|Codling moth|| common oleander|
|Colorado potato bug|| green beans, coriander, nasturtium|
|Cucumber beetle|| radish, tansy|
|Flea beetle|| garlic, onion, mint|
|Japanese beetle|| garlic, larkspur, tansy, rue geranium |
|Leaf hopper|| geranium, petunia|
|Mexican bean beetle|| potato, onion, garlic, radish, petunia, marigolds |
|Slugs|| prostrate rosemary, wormwood|
|Spider mites || onion, garlic, cloves, chives|
|Squash bug|| radish, marigolds, tansy, nasturtium|
|Stink bug || radish|
|Tomato hornworm|| marigolds, sage, borage |
|Whitefly ||marigolds, nasturtium|