This ONE Clever Trick Doubles Harvests and Protects Your Crops

Growing two crops in the same space as one might seem like overcrowding, but there is a clever way we can get double harvests from the same space, without crops suffering. Pro gardeners use this exact method to maximise harvests, reduce pests, and keep weeds at bay. So what exactly is intercropping? Let’s dive in!

Double Your Harvests

Growing two crops together, in the same space, is a gardening technique known as ‘intercropping’, or sometimes ‘interplanting’. It works because the crops grown together are carefully chosen so they don’t compete with each other.

For instance, you could grow a fast-maturing variety of turnip beneath much slower-growing and taller broccoli plants. Lightning-fast turnips take about six weeks to go from seed to harvest, so they’re finished long before the broccoli makes its final push of growth and needs that extra space.

Other fast-maturing crops that are perfect for making opportunistic use of space among slower growers include radish, spinach and salads like lettuce and rocket. So, while I plan specific growing areas for crops like these, if I have any left over after planting – which I invariably do because I always grow a few spares in case of failure – I just plant them wherever there’s space among other slow crops that won’t mind the company. The likes of radish and lettuce are fantastic paired with just about any slower-growing crop – for example among sweet corn, or between newly-planted tomatoes.

Or mark out rows of slow-to-germinate crops such as parsnips by sowing fast-germinating radishes within the same row. Harvest the radishes carefully by gently pulling and twisting for minimal disturbance to the parsnip seedlings.

Lettuces don’t mind sitting in the shade of fruit bushes, especially as we enter the warmer summer months, and the fruit bushes certainly won’t be bothered by these shallow-rooted salads. It’s a match made in heaven!

Intercropping and Companion Planting

Intercropping opens up opportunities to match crops that actively benefit one another. Companion planting like this can help to improve overall growth and even outwit pests.

One example is to grow carrots alongside onions to deter their respective pests: carrot fly and onion fly. Their pests home in on the distinctive smell of their preferred plant, but by growing them together each scent should mask the other, reducing the risk of the flies ever finding their target. Carrots and onions have contrasting leaf shapes too, which should sow further confusion among the flies.

You can set up intercropping in our Garden Planner by positioning plants next to each other on your plan and overlapping the colored backgrounds that show the space requirements for each crop. In most cases this would imply that they’re growing too close to each other, which normally I’d avoid, but for intercropping this is fine because there’s a solid reason we’re maxing out use of the space. For instance, with the carrots and onions example above, the deep-rooted carrots won’t interfere with the shallow-rooted onions, and vice versa.

One of the most famous intercropping combinations is the classic ‘three sisters’ of corn, squash and climbing beans. Growing these three staples together makes clever use of their different growth habits. The tall corn offers support to the climbing beans, which help to fix nitrogen to feed the other plants. The squash then sprawls at ground level where its big leaves shade out weeds and keep soil cool so it doesn’t dry out too fast.

Timing is everything. The corn goes in first then, once the plants have reached about a foot (30 cm) tall, it’s time to sow the beans and squash. The beans are planted at the base of the corn stalks, and the squash around 3ft (90 cm) apart.

Underplanting to Make the Most of Space

Like a few of the examples mentioned today, growing smaller compatible crops under the canopy of larger ones is often known as ‘underplanting’.

For instance, you can pack more into the space you have by underplanting tomatoes with a range of lower-growing plants such as salad onions, lettuce, basil, or French marigolds, which will help to attract pest predators like tiny wasps.

Underplanting like this works because the shallower roots of salads and basil won’t impact the growth of the tomatoes, which will produce a far more extensive root system to draw on all the nutrients and moisture they need to support what will be substantial top growth. In a very small way, it’s a bit like the layers of a forest – the tree layer, then shrubs and smaller plants below. We’re kind of copying the way nature does things.

Just about any climbing or vertically trained crop can be underplanted to get more from the space you have. Try growing shade-tolerant salads underneath cucumber vines, for example. In fact, planting any low-growing, cool-season crop beneath taller sun lovers is a very savvy strategy.

This year I’m trialling a new method of supporting climbing beans. Rather than growing the vines up vertical supports like bamboo canes, my setup trains the vines initially up, off the ground, then out horizontally along bars. But rather than leaving the area below vacant, I’m underplanting it with courgettes, grown far enough from the roots of the beans not to interfere with their growth.

There are many ways to intercrop, and I hope this has given you some ideas for your garden. The Garden Planner can help you pick the best companions for anything you want to grow, making it a great starting point to plan clever intercropping combinations. Try the Garden Planner for free with our no obligation, no payment details needed trial.

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