There’s a classic book called Carrots love Tomatoes that was written by a North American woman, Louise Riotte, nearly four decades ago.

Considered by many to be the “bible” of companion planting, it was first published in 1975, and is still on the bookstore bookshelves years after her death in 1998. But in those days the idea of growing particular plants together for mutual benefit was something most backyard gardeners either rejected or failed to consider.

Today, with the ever- growing trend of things organic, and an increasing awareness of the need for sustainability, home gardeners – and many commercial gardeners for that matter – are practicing companion planting, along with crop rotation, green manuring and other natural pursuits.

Why Tomatoes Need Companions

While the companions favoured by different plants vary, the reasons for companion planting are essentially (within broad parameters) the same for all of them. While not all companions fulfil the same function, broadly speaking certain companion plants will:

• attract bad bugs
• attract good, beneficial bugs
• assist pollination
• feed and nourish the soil
• provide shade
• provide support

The end result is that by planting good, suitable companions for the vegetables and other plants you are growing, you will find that you are able to minimise the pests in your veggie garden and produce beautifully healthy, organic crops for the table.

The Tomato’s Favourite Companions

Plants that are acknowledged to be the tomato’s best friend are asparagus, basil, cucumber, gooseberries, marigolds, nasturtiums, onions and other members of the onion family, including chives, parsley, stinging nettles and yarrow. They are also compatible with garlic.

Of course carrots are also reputedly an excellent companion for tomatoes, although oddly enough Louise Riotte doesn’t explain why in her book about companion planting. She had an article published on the Internet in 1992, titled Carrots love Tomatoes: Companion Planting for a Healthy Garden, and she doesn’t elaborate there either! Carrots have antiviral properties which might be why tomatoes like them; although the Riotte book’s title seems to state that carrots benefit from tomatoes, not necessarily the other way around. Tomatoes certainly protect roses against black spot, although roses don’t necessarily benefit from tomatoes. And it is the active solanine (a powerful natural insecticide) in tomato leaves that is so special … so maybe this is what the carrots like too.

It is this way with all companion plants, and in this instance, some like tomatoes, while tomatoes benefit from others. Marigolds probably come out tops, since they have a powerful active ingredient that gets rid of the nematodes (or eelworms) that so often attack tomatoes.

Plants that Tomatoes Don’t Like

Tomatoes belong to the nightshade family (solanaceae), as do peppers, eggplants (aubergines), and Irish potatoes, and it is a golden rule in gardening not to grow plants from the same family together. They simply don’t like one another, and therefore won’t thrive.

The other family of plants that tomatoes despise are the brassicaceae – members of the cabbage and mustard family. These plants include broccoli, Brussels sprouts, cabbage and Chinese cabbage, cauliflower, collards, kale, kohlrabi, mustard greens, radishes, rutabaga, and turnips.

They also hate fennel … but then so do most other vegetables.