Summer squash, courgettes, winter squash and pumpkins are all within the Cucurbita plant family.These plants can all be excellent choices for a polytunnel garden. But to reduce the incidence of pest problems, and boost yield, it is best to plant them alongside companion plants for squash and pumpkins.
Companion planting can improve environmental conditions, attract pollinators and other beneficial insects and help gather the nutrients that these hungry plants need. For centuries, growers have been improving their yields and maintaining healthy gardens by creating polycultures that take advantage of the beneficial interactions between plants.
All cucurbita like summer warmth, so can benefit from the extra protection a polytunnel can provide here in the UK. But which plants are the best companions for these plants? If you are trying to work out what to plant alongside them, this list of excellent companion plants for squash and pumpkins will give you a good place to start:
Other Fruits and Vegetables That Are Good Companion Plants For Squash
To begin with, let’s take a look and which other fruits and vegetables you should consider growing alongside your squash and pumpkins.
One of the best and most popular companion planting combinations is the ‘three sisters’ polyculture. This plan, used by Native Americans and often now included in permaculture garden designs, involves planting squash or pumpkins around sweetcorn and summer beans.
Sweetcorn – Sweetcorn (or other corn in warmer climes) is the ‘supporting sister’ in the three sisters planting scheme. The sweetcorn grows tall and provides a little shade for the surrounding squash, and also provides support for vining beans to climb.
Beans – Beans, another ‘sister’ to squash, is the ‘giving sister’. As a nitrogen fixer, beans co-operate with bacteria in their root nodules to fix nitrogen from the air and make it available in the soil. As ‘hungry’ plants, squash and pumpkins may benefit from the nutrition this ‘sister’ can help to provide. In return, the squash or pumpkins shade the soil, and their spiky stems and foliage can also sometimes help to discourage pests. By shading the soil, the plants reduce moisture loss and protect the fragile soil ecosystem to help their sisters grow strong.
Peas – But when creating a polyculture, you could also consider branching out from the traditional three sisters scheme. Peas are another nitrogen fixing plant that could be planted close to squash or pumpkins as an alternative companion plant. They too can help to provide the nutrients needed by your plants as dynamic accumulators, acquiring nitrogen from the air and making it available in the soil.
Tomatoes – Tomatoes require similar growing conditions to squash through the summer and so can also be considered as companion plants. Your tomatoes and squash may thrive when planted alongside borage (more on which a little later in this article).
Radishes – Radishes are a great companion plant for cucurbita because they can be effective as a trap crop for flea beetles that might otherwise harm your squash or pumpkin plants. They can also be used to make the most of the space in your polytunnel. They’ll fill in gaps and be harvested before the squash or pumpkins need the space and nutrients. Or they can be left to flower and go to seed, for pest repelling properties and to draw in pollinators and other helpful insects.
Herbs That Are Good Companion Plants For Squash and Pumpkins
In addition to planting other fruits and vegetables alongside your squash, you should also consider planting herbs. Here are some herbs that make good companion plants for squash and pumpkins:
Mint – Mint is a herb that can be a good companion for cucurbita because it can draw in pollinators to make sure your cucurbita set fruit well. It can also harbour a range of other beneficial insects that will help keep pests at bay. Mint also spreads to create good ground cover around your summer crops, to retain soil moisture in your polytunnel.
Rosemary – Rosemary is another great companion plant for squash and pumpkins. This Mediterranean herb will also thrive in the warm conditions required by your cucurbits, and when planted on a drier edge to your growing area, can also draw in a range of pollinators and other beneficial insects.
Oregano – Oregano is another flowering herb that can help your squash and pumpkins by drawing in the pollinators to ensure a good yield. This, rosemary and other Mediterranean herbs will be particularly beneficial in this regard when left to flower.
Tansy – Tansy is said to help in repelling a number of pest species that may plague your squash, including certain beetles. So planting this herb nearby may help to keep your squash and pumpkin plants healthy and strong.
Catnip – Catnip is another herb that can repel certain pests and attract in some beneficial insects to help you in your organic pest control efforts.
Flowers That Are Good Companion Plants For Squash and Pumpkins
Finally, let’s take a look at some flowers that are good companions for your squash and pumpkins. (They’ll work well with many other crops too, so are fantastic dotted all around your various growing areas.) Again, these are just a few top examples:
Nasturtiums – Nasturtiums are one of the best companion plants for squash and other members of the cucurbita family. These flowers are actually a food crop in their own right. They offer edible flowers, leaves and buds or seeds, that can be pickled like capers. But more than this, nasturtiums are a great trap crop, which can draw flea beetles and other pests away from your cucurbita. Its flowers are also great for drawing in those pollinators and beneficial insects.
Marigolds – Marigolds, like nasturtiums, also bloom over a long season. Interestingly, French Marigolds (Tagetes patula) and Pot marigolds (Calendula) are also edible. The petals can be used in salads, or to add colour to a wide range of recipes. Tagetes patula also offers additional benefits. It may help reduce harmful nematodes in the soil, and is anecdotally said to repel a wide range of pest species. Marigolds are one of the best companion plants out there. They can benefit a range of other plants when grown close by.
Borage – Borage is one of the best companion plants for drawing in the bees. Planted alongside squash, or other fruiting plants, it can help to ensure that there are enough pollinators around to ensure good pollination. It won’t just attract bees. It will also attract a range of other pollinators and beneficial predatory insects.
What To Avoid Planting Near Squash and Pumpkins
As mentioned above, squash and pumpkins are ‘hungry’ plants that require plenty of nitrogen and other nutrients to grow and crop well. For this reason, it is important to make sure that they do not have too many plants that will compete for those nutrients planted close by.
Potatoes should definitely not be grown close to your squash and pumpkins. The potatoes have a growth inhibiting effect on certain other crops, and are heavy feeders. What is more, they could also disrupt the shallow roots of the squash plants and make them less strong and healthy.
You should also take care not to plant too many hungry leafy crops with shallow roots close by. These will also compete with the squash for nutrients and could reduce the vigour of your plants and the overall yield you can obtain from them.
One final thing to consider is whether or not you will be collecting the seeds from your squash or pumpkin plants. If you intend to do so, you will have to make sure that your chosen variety is separated from other plants with which crop pollination can occur. Otherwise you might end up with squash you did not intend – and may not even get an edible crop next year.
Do you grow squash or pumpkins in your polytunnel? What do you grow alongside or between them? Share your companion planting tips for squash and pumpkins in the comments below.
Elizabeth Waddington is a writer and green living consultant living in Scotland. Permaculture and sustainability are at the heart of everything she does, from designing gardens and farms around the world, to inspiring and facilitating positive change for small companies and individuals.
She also works on her own property, where she grows fruit and vegetables, keeps chickens and is working on the eco-renovation of an old stone barn.