Tomatoes and basil; pumpkin and sage; cucumbers and chives. These are friendships born in heaven.

Some gardeners believe that the reason some foods are companions on the plate is because they are also companions in the soil. Basically, tomatoes and basil are inseparable.

It’s known as “companion planting”, or what we like to call “plant BFFs”.

Plants release a variety of nutrients into the soil, and different plants require different nutrients. Some, when grown together, can have mutually beneficial relationships.

The key to a brimming veggie patch is diversity, says Mat Pember of St Kilda’s Little Veggie Patch Co. “When planting different things next to each other, they can either help or hinder each other’s growth.”

“There are studies that suggest growing basil and tomatoes together can enhance their flavours, but for whatever reason, we’ve always found that both plants grow so much better together.”

Basil plants, which can be grown all year round, also ward off fruit flies, mosquitoes, spider mites, aphids and hornworms. In this way, they can help protect the vulnerable tomato fruit.

“Basil is a tough plant and quite tolerant of summer sun. But we’ve found that when we grow tomatoes and basil side by side, the basil plant will grow at least twice as large, compared to when it grows out in the open,” Pember explains.

For some plants, the reason can be as simple as different root lengths. Placing a plant with long roots next to a plant with shallow roots will mean they are not competing for each other’s nutrients or water.

Another interesting one is runner beans and corn. Corn requires high amounts of nitrogen in the soil and can grow quite tall. Beans, on the other hand, produce lots of nitrogen and need a structure like a tree trunk or trellis frame to hold onto as they grow.

But not all plants get along. Brassicas (broccoli, cauliflower and cabbage plants) are “hungry crops” that require lots of water and nutrients and can deplete the soil’s supply. Keep them away from tomatoes, chilli and strawberries.

Pember also says mint is not a team player. “It needs to be kept away from everything because the root growth is so vigorous. It tends to strangle out the other plants, so make sure it’s in a separate pot.”

Companionships are also season dependant. The means plants that grow well together naturally grow best at the same time of year.

“In summer, the best things to plant are chillis, capsicum and eggplant, which love the heat. Salads and leafy greens grow well with these and can be grown anytime,” says Pember.

These summer veggies grow best around herbs like parsley and basil, and require a soil pH level from 5.5 to 7.5.

Beetroot, radish and carrots also grow well in summer, according to Pember, and help break up the soil, promoting aeration and allowing more nutrients to be accessed by the roots of all plants in the garden bed.

If you’re short on space, herbs and chillis will grow well in pots over summer. Firstly, ensure you have rich, free-draining soil. Pember’s tip is to use the best quality potting mix you can find, as well as compost from a worm farm on your plants. But balance is paramount.

“Think of it like a lasagne”, he says. “You need to get even layers of green waste (food scraps) and brown waste (straw and paper waste). If there’s too much green waste, that’s when it starts to smell like a rubbish tip.”

Also – always upsize your pots and don’t plant seedlings too close together. Pember says the most common mistake is choosing a pot that’s too small, which hinders root growth and causes the plants to dry out.

Finally, only grow what’s in season and what’s best for the climate. In summer, put your seasonal veggies in full sun and make sure you give them a little extra water.