Planting Companion Guide: Best Plant Combinations

Companion planting or companion gardening is an age-old methodology that has been around for centuries. This technique involves growing a combination of plants together that have a positive effect on each other to gain mutual benefits. Planting the right combination of plants can improve each plant's health and growth and enhance the overall beauty of your garden. 

By encouraging plant communities in the same bed, container or pot, you use polyculture rather than monoculture, where you grow the same plant in one area. 

Benefits of companion planting:

• assisting plants in taking up nutrients
• encouraging natural predators of garden pests, such as predatory insects
• attracting pollinators to your garden, such as bees and butterflies
• creating the right conditions for plants, e.g. by creating natural shade for plants that don’t like full sunlight
• minimising the risk of diseases attacking your vegetable plants
• pest control, as some plants will discourage common pests
• improving the growth and health of your plants and maintaining a healthy soil
• saving space, as this method allows you to place your plants closer together
• reducing the proliferation of weeds
• improving the flavour of your crop

Best combinations of plants to plant together:

Tomatoes and Basil:

Tomatoes benefit from basil’s ability to repel pests, improve their flavour, and boost the health and vigour of the tomato plant. 

There are also several other plants which, when grown alongside tomatoes, will soon have your tomatoes tasting and looking terrific. Chives are known to deter pests and attract pollinators. Lettuce will fill the gaps to ensure good soil coverage to keep weeds at bay, reduce the risk of diseases and help with moisture retention in the soil. Borage is also reputed to improve the flavour of tomatoes. Planting lettuce around your tomato plant will reduce weeds and minimise the risk of diseases. 

Thyme is also said to improve tomatoes' flavour, and this Mediterranean herb also deters aphids, blackflies, and whiteflies. Similarly, mint has a pungent scent that repels aphids, one of the most common tomato pests, and other pest insects. 

Nasturtiums are often used as a trap or martyr crop when planted with tomatoes, as aphids and whiteflies love it and will leave your tomatoes in peace. Those nasturtiums the aphids don’t attack make gorgeous edible additions to salads. Asparagus repels nematodes, and in turn, the tomatoes deter the asparagus beetle. So, planting these two together will be a win-win! 

Carrots and Radishes:

Carrots can benefit from radishes' ability to loosen the soil and deter pests. Radishes provide good ground cover, preventing weeds from growing and reducing the risk of diseases. 

There is a range of additional plants that you can grow with carrots that will help keep them pest free by repelling them. Tomato plants release a chemical called solanine, which repels the carrot fly. But make sure you plant your carrots 40 cm (15 in) away from the tomatoes because if they are too close together the growth of the carrots could be inhibited. 

Members of the allium family, such as leeks, onions, and spring onions, repel carrot flies by confusing them with their strong scent. Attracting natural predators of various garden pests can help keep numbers in check and ensure a good carrot yield. Attracting pollinators is always beneficial for your vegetable garden, and companion planting for vegetables can help in this respect. Chives attract pollinators like bees and beneficial insects such as hoverflies and ladybirds. 

Peas are suitable companion plants for carrots to increase their condition and boost their yield. The taller plants will provide shade for your carrot crop and keep them cool and release nitrogen into the soil, giving your carrots the nutrients to flourish. Like peas, beans are nitrogenous plants that release nitrogen into the soil. Lettuce will also provide shade for carrots and will keep the soil cool.

Marigolds and Vegetables:

Gardener’s value these pretty and popular plants for more than their cheerful and attractive appearance. Marigolds produce a natural pesticide that can protect neighbouring vegetables from pesky pests and harmful bugs. Marigolds have a distinctive aroma that may discourage rabbits from feasting on your prize veggies or munching your favourite flowers.

Marigolds can also be used as a trap crop to lure snails and slugs away from your vegetables, such as young courgette plants. Several other vegetable plants can benefit from adding marigolds in the garden, such as aubergines, onions, cucumbers, squash, melons, potatoes, lettuce, tomatoes, asparagus, pumpkins and beans. When planting other plants as marigold plant companions, select those that share similar growing conditions. Marigolds are drought-tolerant plants that flourish in hot, sunny weather, and well-drained soil is an absolute must.

Beans and Corn: 

This is another companion-planting dynamic duo! Beans and corn are a great plant combination as they can help enhance each other’s yields. Beans can provide nitrogen to the corn's soil, while the corn provides shade and support for the beans. One of the most important benefits is that they complement each other nutritionally. Beans provide protein, while corn contributes carbohydrates. This makes them perfect for people who want a nourishing nutrient-packed boost from their veggie garden.

Another benefit of growing corn and beans together is that they can protect each other from diseases and pests. Beans produce a chemical that deters corn rootworm, a common pest that attacks both crops.

Lavender and Rosemary: 

Rosemary and lavender are another classic pair. These beautifully scented and versatile herbs can deter pests and improve each other's growth and flavour. Both hail from the rocky hillsides of the Mediterranean, and if you want to expand your herb garden that already has well-established lavender, rosemary is one of your best bets.

This herb requires just as much sun and water as lavender. They can be planted together as companion plants to benefit the rest of your garden. As an added benefit, lavender and rosemary attract various pollinators and deter deer and rabbits. Rosemary is not as tolerant of the cold as lavender, so if you live in a cooler climate, you may have to consider another companion plant.

Things to consider when planning your companion planting efforts: 

• When choosing plant combinations, consider factors such as soil, water and light requirements, as well as each plant's growth habit and size.
• Companion planting is at it’s best with variety - try planting different varieties of the same crop in various parts of the garden.
• Interplant crops with alternate timing. As cool-season crops taper off, add warm-season crops. Once the cool-season crops have been harvested, the warm-season crops will be ready to take up the extra room.
• Add perennial herbs to your garden beds.

Plant combinations for happy gardeners

You can create a thriving, healthy garden bursting with diverse and beautiful plant combinations using companion planting. As they say: variety truly is the spice of life!