1. Companion PlantingThis is a cultural system where two or more plants are grown in close proximity in order that they mayprovide some form of benefit to one or all of them. This could be to deter or act as a decoy for pests anddiseases, or improve growth and flavour. Usually it is the aromatic foliage or flowers of the companionplant which deters the pest or draws it away. The improvement in growth or flavour is probably due to the companion plant adding some of the micronutrients or the roots may support microorganisms which improve their uptake. In the case of legumes they fix nitrogen, and White Clover is included in some grass seed mixes, for this reason - it is also drought resistant so greens up quicker than grass when used in lawns. Some plants exude protective chemicals (allelochemicals) from their roots or foliage which can deter pests, eg. African Marigolds produce thiopene which repels nematodes so it makes a good companion plant for root crops which are attacked by nematodes. This is given the title Allelopathy. Tall plants can provide shelter for lower-growing ones and create a microclimate allowing them to thrive where they may not normally grow. This may also protect them from pests Beneficial insects can be attracted to a cropping area by planting something which they use as a food nearby, eg. adult Hover Flies feed on nectar,but their larvae feed on aphids so planting nectar-rich flowering plants will attract them.Marigolds and Garlic have a reputation for repelling a number of insect pests such as Aphids and CarrotRoot Flies. The Mexican Marigold, Tagetes minuta or Muster-John-Henry, is an annual which grows toabout 1.2 m (the species name refers to the flowers not the height of the plant) The roots have aninsecticidal effect on nematodes and some effect on keeled slugs. The secretions responsible begin about3 months after sowing and also affect the growth of Ground-elder (Aegopodium podagraria), Bindweed(Convolvulus arvensis), Couch grass (Agropyron repens), Lesser Celandine (Ranunculus ficaria )andGround Ivy (Glechoma hederacea). It is grown as a half-hardy annual which can be planted out after therisk of frost has passed, but this does not usually give them a long enough growth period to flower andset seed in Britain. Deadheading prolongs the growth for protection purposes. CROP COMPANION PLANTS INCOMPATIBLE WITH Asparagus Tomato, Parsley, Basil Beans Most Vegetables & Herbs Potato, Cucumber, Maize, Strawberry, Celery, Beans, Broad Onion Summer Savory Onion, Beets, Kohlrabi, Beans, Runner Maize, Summer Savory, Radish Sunflower Aromatic Herbs, Celery, Beetroot, Onion Family, Dill, Strawberries, Runner Cabbage Family Chamomile, Spinach, Chard Beans, Tomato Pea, Lettuce, Rosemary, Onion Family, Sage, Carrots Tomato Onion & Cabbage Families, Tomato, Broad Beans, Celery Dill Nasturtium Cucumber Beans, Maize, Pea, Sunflowers, Radish Potato, Aromatic Herbs Aubergine Broad Beans, Marigold (Eggplant) Lettuce Carrot, Radish, Strawberry, Cucumber Maize (Corn) Potato, Broad Beans, Pea, Pumpkin, Cucumber, Tomato
2. Squash Melon Maize, Nasturtium, Radish, Onion Family Beetroot, Carrot, Lettuce, Cabbage Family Beans, Peas Parsley Tomato, Asparagus Peas Carrots, Radish, Turnip, Cucumber, Maize, Beans Onion Family, Gladiolus, Potato Beans, Maize, Cabbage Family, Marigolds, Pumpkin, Squash, Tomato, Potato Horseradish Cucumber, Sunflower Pumpkins Maize, Marigold Potato Radish Pea, Nasturtium, Lettuce, Cucumber Hyssop Spinach Strawberry, Cauliflower, Celery Squash Nasturtium, Maize, Marigold Potato Strawberry Broad Beans, Lettuce, Onion, Spinach Cabbage Basil, Onion Family, Nasturtium, Marigold, Tomato Potato, Fennel, Cabbage Family Asparagus, Carrot, Parsley, Cucumber, Mint Turnip Pea PotatoThis is a table of herbs which can be used to repel insects and the plants they can be used to protect. Thefinal column gives the plants for which they are bad companions and some other points of note. HERB COMPANION FOR PESTS REPELLED INCOMPATIBILITIES aphids, carrot flies, vegetables, fruit Allium (Onion Family) moles, tree borers, peas and beans trees and weevils Angelica (Angelica Dill archangelica) Basil (Ocimum Tomatoes Flies, Mosquitoes Rue basilicum) Bay leaves beans or grains weevils and moths Borage (Borago Tomatoes, Squash, Tomato Worm officinalis) Strawberries Caper Spurge or Mole poisonous, irritant milky Moles and Mice Plant (Euphorbia lathyris sap Good for loosening Caraway (Carum carvi) Avoid Dill the soil. Castor Oil Plant (Ricinus Moles seeds extremely poisonous communis). Catnip (Nepeta cataria) Aubergine Flea Beetle, Ants Chamomile Cabbage, Onion (Chamaemilum nobile) Coriander (Coriandrum all vegetables Aphids attracts Bees sativum) Chervil (Anthriscus Radish cerefolium )
3. Chives (Allium Carrots Root Fliesschoenoprasum)Dill (Anethum Cabbage Carrots and Carawaygraveolens)Fennel (Foeniculum Most plantsvulgare)Feverfew(Chrysanthemum Roses attracts Aphids away seeds freelyparthenium syn.Tanacetum parthenium)Garlic Roses, Raspberries AphidsHenbit (Lamium General Insectamplexicaule) RepellentHyssop (Hyssopus Cabbage White Cabbage, Grapes Dislikes Radishesofficinalis ) Butterflies Moths - make sachetLavender (Lavandula with southernwood,angustifolia) wormwood and rosemary, use in doorsMarigolds (Tagetes sp.) Good companion to Nematodes, Aphidsmost have aromatic most plants and othersfoliageMexican marigold Good insect repellant,(Tagetes minuta), inhibits ground-elderMuster-John-Henry and some other weeds Cabbage WhiteMint (Mentha sp. ) Cabbage, Tomatoes Butterflies, Aphids, invasive roots Flea Beetles cabbage, cauliflower, radish,Mustard (Brassica a trap crop to attract brussel sprouts,juncea) many insect pests turnips, and kohlrabi Radishes, Cabbage, Aphids, Squash Bugs,Nasturtium (Tropaeolum Squashes and Striped Pumpkinmajus) Pumpkims, fruit Beetle treesOregano(Origanum Brassicas Cabbage Butterfliesvulgare)Pennyroyal (Mentha Flies, Mosquitoes, Roses invasive rootspulegium ) Fleas, othersPetunia (Petunia Beanshybrida) Tomato Worm,Pot Marigold (Calendula Tomatoes Asparagus Beetles,officinalis) WhiteflyPyrethrums Dried flower heads(Chrysanthemum make an insecticide.cinaeriofolium)
4. Rosemary (Rosmarinus Cabbage, Beans, Cabbage Butterflies,officinalis Carrots, Sage Bean Beetle, Carrot Fly Roses andRue (Ruta gaveolens) Japanese Beetles Dislikes Sweet Basil Raspberries Rosemary, Cabbage Moth, CarrotSage (Salvia officinalis) Dislikes Cucumbers Cabbage, Carrots Fly, Flea Beetle, SlugsSouthernwood Cabbages Cabbage Butterflies(Artemesia abrotanum)Summer Savory Beans Bean Beetles(Satureia hortensis ) Flying Insects, Japanese Beetles,Tansy (Tanacetum Fruit Trees, Roses, Striped Cucumbervulgare) Raspberries Beetles, Squash Bugs, Ants, FliesThyme (Thymus Cabbage Cabbage Wormvulgaris) Moths, Slugs, Carrot Fly. Plant at Fresh material will stuntWormwood (Artemisia boundaries to keep growth of young plants, useabsinthium) animals out of the dried sprigs garden. Plant near aromatic Attracts Hover FliesYarrow (Achillea herbs to enhance and their larvae preymillefolium ) production of on Aphids essential oils.