Companion Planting for Vegetables, Herbs and other Garden Flowers and Plants
One only has to look at the old-age tradition of North American agriculture of planting corn, beans and squash together. Corn grows tall, trying to steal as much sun as possible and taking out a lot of nitrogen from the soil. Beans grow up the stalks of the corn looking for the sun too, but putting nitrogen back into the soil. Planting squash at the same time does well on the conditions and grows and spreads on the ground growing and harvested long after the harvest of the beans and the corn. Therefore, by intercropping, or companion planting, you have been able to grow 3 different vegetables in the same space as you would one.
Companion Planting for Deterring Insects
Although many will disregard companion planting and see it as old wives’ tales, many plants, flowers and herbs 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 practice 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 neighbors will be protected. It may be significant that most of these beneficent plants are strongly aromatic. Planting dill with your tomatoes will attract the tomato worm for you.
Planting nasturtiums will take care of cabbage white butterfly caterpillars and great for repelling white fly. They are also good for planting under apple trees to get rid of colding moth. Nasturtiums are planted among cucumbers for protection against the cucumber beetle and the Mexican bean beetle. Nasturtiums and tansy help get rid of the Colorado potato beetle, and catnip and nasturtiums for repelling the green peach aphids.
If you want to get rid of aphids then you will need to interplant with sow thistle, stinging nettles or broad beans. Sunflowers will help trap harlequin bugs, and potatoes, calendula daisies are good for earwigs.
Companion Planting for Benefiting other Plants
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.
Companion Planting for Attracting good Insects
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.
Daisies, dill, coriander and parsley are all good for attracting beneficial insects into the garden. The pollen they provide make them wonderful bee plants, but in addition they also attract parasitic wasps that prey on insect pests. These plants should be planted throughout the garden at regular intervals as many of these wasps are tiny and fly only over short distances.
Larger predatorial insects like lacewings and hoverflies also feed on the pollen. By allowing these plants to go to seed, not only are you keeping the insect population in check, but you can save seeds at the same time for next planting season.
Herbs too have been known to repel certain insects. Southernwood is good for repelling the cabbage butterfly and tobacco for flea beetles.