Companion Planting is the idea that some plants have a beneficial effect on others growing nearby and other plants have a detrimental influence. This is an ancient one that was seen during the times of the Romans, and perhaps even before then. Although many will disregard companion planting and see it as old wives' tales, many plants do defend themselves against insects by being poisonous to them or developing a strong scent that frightens them away, and it is possible that a plant growing close by might benefit from being in this bug-free zone. So, although companion planting is also mixed up in folklore, there is also an element of fact and this method can be happily adopted by those who practise organic gardening.
For example, French marigolds (Tagetes patula) secrete an enzyme or a hormone into the soil that deters nematodes from infesting their roots, and it does seem that tomatoes or other nematode susceptible plants growing as neighbours will be protected. It may be significant that most of these beneficent plants are strongly aromatic.
Many times, planting certain plants together is also for practical reasons. Planting lettuce next to corn means that the lettuces can be shaded during hot summers. When you plant cabbages in the late summer, at the same time, and in the same bed, you can also plant garlic. Where cabbages will use of a lot of nutrients, and where the cabbages will be harvested in the autumn, the garlic will continue growing until the following summer resulting in good crops for both. Chives and onions planted near carrots will help also deter the presence of carrot rust flies.
Radishes when planted next to Chervil benefit from the shade the herb casts, and the result is lovely juicy radishes that are not woody at all. Beans are heavy feeders and therefore it is advisable to companion plant it with something less greedy. Therefore mustard is a perfect companion.
The common dandelion that some see as a scourge in the garden should think again. It is now known that dandelions attract pollinating insects. Furthermore, they also release ethylene which is a gas that encourages fruit setting and fruit ripening.
Herbs too have been known to repel certain insects. Nasturtiums are great for repelling white fly, southernwood for repelling the cabbage butterfly, tobacco for flea beetles, catnip, coriander, nasturtiums and tansy for getting rid of the Colorado potato beetle, and catnip and nasturtiums for repelling the green peach aphids.
Good Companion Plants
Basil with tomatoes, asparagus, beans, grapes, apricots and fuchsias
Beans with potatoes and sweet corn
Borage with strawberries
Chives with carrots, cucumbers and tomatoes
Citrus with guavas
Cucumbers with potatoes
Garlic with roses, apples, apricots and peaches
Geraniums with grapes
Grapes with mulberries
Horseradish with almost any fruit tree
Hyssop with cabbages and grapes
Irises with roses
Leeks with celery
Lettuce with carrots, onions and strawberries
Marigolds (French) with tomatoes, roses, potatoes, daffodils and beans
Melons with sweetcorn
Mint with cabbages and other brassicas, and peas
Nasturtiums with cucumbers, zucchini, squash
Onions with carrots, kohlrabi and turnips
Parsley with roses, asparagus and tomatoes
Peas with carrots
Roses with grapevines
Sage with cabbages
Sunflowers with squash and sweetcorn
Thyme with any Brassica
Wallflowers with apples
Bad Companion Plants
Apples with potatoes
Beans with beets
Beans with garlic
Cabbages with strawberries
Gladioli with strawberries, beans and peas
Hyacinths with carnations
Mint with parsley
Sunflowers with any vegetable but squash
Wormwood with just about everything
So next time you are planting your vegetables and flowers choose their neighbours carefully. When looking at people some neighbours are helpful, beneficial and nice to have around. Others are spawned in Hell and do untold damage. Make sure that the next time you plant out, you choose good neighbours for your flowers and vegetables!
Companion Planting - Planting Tips For Organic Gardening