Companion planting is not a new thing. It has long been known that certain plant species have mutually beneficial effects when they are planted together. Each plays a part in the system. In many places in the world, people apply the agricultural knowledge to improve the yield of food crops. Definitely, the planting method can also be applied on a smaller scale. If you are into home food production, interplanting compatible crops will allow you to use garden space efficiently. There are some considerations, however, before adding new plants to your garden.
Before anything else, think about what you want to achieve. Think in terms of which plants can help the existing ones grow. If you are growing fruit trees, you can try to plant beans beneath them. Beans will interact positively with fruit trees by adding nitrogen to the soil. In North America, corn, beans and squash are planted together for better yields. Taller corn support beans, and in return, beans provide atmospheric nitrogen to the corn and squash. The broad leaves of squash create healthy ground cover, preventing the loss of moisture in the soil. Lupin, wildflower which is actually a legume, can also be used to fix nitrogen for your trees’ high needs.
If you are into veggies, intercropping radishes with lettuce is something worth trying. Lettuce, as you know, is one of the easiest plants to grow from seed. Not only it is an easy plant to grow and maintain, the leafy green can yield more than one crop per season. More than that, the leaves of the plant will serve as a living mulch to prevent moisture evaporation, helping the other plants get established.
Some people employ mixed plantings in order to minimize pest problems. The use of living plants to discourage harmful insects is definitely a great way to reduce the need for chemical treatments. Garlic, for example, is a good companion for tomatoes, as it can act as a natural repellent for red spider mites. Garlic, as well as onions, also makes a good team with fruit trees. They repel fruit tree borers that attack the woody parts of apple and pear trees. Onions and garlic are also beneficial as a pest repellent for insect pests that favor celery and carrots.
Another purpose of companion planting is to attract pollinators. Flowers like Spring bulbs, for example, can help with pollination by attracting bees. Talking about pollination, it is worth noting that fruit trees are either self-pollinating or require a pollinating partner to successfully bear fruit. If you are growing apples or pears, the technique of multiple planting may be needed for fertilization to occur. When choosing a good companion for them, you can simply opt to plant another cultivar of the same species to meet their pollination requirements.
While it is true that mixed planting offers various advantages, it is important to know what not to grow. To minimize nutrient competition, it is best to select species with different structures of roots. Cabbage, for example, goes well with carrot as they have different rooting patterns. Also do not forget that some plants can be somewhat invasive. Pairing cabbage family plants with strawberries is not a good idea. The rapid growth of strawberry may offend your older plants. Chemical or flavor interactions is another thing to consider. Growning onions and beans in the same spot is something to avoid.
When it comes to companion planting, many relationships have not been scientifically verified. Furthermore, there is no one magic solution. Like borage, marigold seems to benefit a wide variety of plants. It discourages various harmful insects. Even so, not all plants will tolerate its presence. With all that being said, growing a diverse mix of plants is usually beneficial. Your own experiments with different combinations and arrangements will in the end help you create a harmonious garden. Many resources are available which can be a good starting point.