|Companion Planting for Vegetable Patches|
What if everyone around you was exactly like you? That sounds to me like some kind of perfect hell. Well the first and foremost rule of companion planting is diversity. There are a lot of books written on this subject, filled with long lists, many of which contradict the other. We say don't get too carried away by matching each plant according to someone's list. There are however a some simple rules to grow by. We'll expand on each below:
Competition for Nutrients
If all the plants are the same, they are competing for exactly the same nutrients at exactly the same root depths. Planting plants that have different root-depths next to each other ensures that the plants are not searching for nutrients in the same areas.
Therefore, if we plant a row of lettuce, then a row of carrots, then a row or tomatoes we are reducing the competition between these plants because their roots are accessing nutrients from different areas. These will be healthier plants. If you don't know how deep the plant roots are (Robert Kourik's Roots Demystified has many diagrams) don't worry! Just get a diversity of plants together and it's better than a monoculture.
Natural Growth Stimulants
Plants that are considered to have a positive effect on a wide range of nearby plants include chamomile, yarrow, parsley and lemon balm. These small plants are great to plug and bare gaps in your garden with. They’re also great to plant around the borders of your garden, and have uses of their own.
Natural Growth Suppressants
Some plants that often have a negative effect on each other, and should not be planted next to each other include:
SOLUTION: Beans and onions both grow well next to broccoli/cauliflower, so plant your row/s of beans, then broccoli, then onions. In this case the broccoli is called a “barrier plant”, as it is keeping apart the plants that don’t work well together
Strawberries are perennial plants (they live for more than one year) whereas the other vegetables mentioned are all annuals (they live for less than a year). In general you should keep your perennials and annuals separate because you don't want to disturb the soil around your perennials, and each group prefers and establishes different soil biology.
Eucalypts and some other plants are allelopathic, meaning that they produce toxins suppressing nearby plant growth, so you need to keep your vegies protected from their root systems.
A single monoculture of one type of plant is like a giant landing strip for pest insects. Non-flying pests can walk from one plant to the next. Pest insects find your plants by both sight and smell. Creating a diversity of plants confuses them. Mix your plantings up so plants of the same or similar type aren't next to each other, and plant strong smelling plants like nasturtiums, wormwood, rosemary and lavender nearby.
Certain plants attract predator insects. These include plants from the daisy family, the Umbelliferae family (think parsley, carrots, fennel, celery etc) when flowering, yarrow and alyssum. Dense prickly habitat shrubs for small birds nearby helps too, as does a pond which brings in beneficial insects, frogs, lizards and more birds.
We can use our plants to create shade for each other. For example, lettuce and celery do not last for as long if they receive too much summer afternoon sun. In contrast, eggplant and capsicum love full sun light. Therefore, if we plant the lettuce among or to the south east of the eggplant and capsicum, both will be receiving their preferred amount of sun, and will grow better.
Now think of all your little plants out there growing harmoniously in companionship! If only we could learn from them the world would be alright.