We have all heard by now of the benefits of good companion planting and the result that can be achieved from using a harmonious, intercropping techniques like the three sisters system. The correct kind of companion planting may yield a stronger, healthier crop as well reduce labour, as some plants can be used to suppress weeds or even improve soil quality.

Three sisters vegetable gardening
Three Sisters Vegetable Garden

Meet the Sisters!

The ‘three sisters’ approach to gardening is an excellent ‘inter-cropper’ that has recently gained merit with many gardeners around the world. Since ancient times, the Souix Indians of North America have used this initiative method for growing three staple crops; sweet corn, squashes and runner beans. The great thing about a three sisters garden scheme is that these three crops are all grown together and interwoven in the same plot of earth.

Each crop compliments the other

  • Sweetcorn provides a support for the runner beans and offers minimal shade over the squashes.
  • Runner beans improve the soil by adding nitrogen, feeding the other two crops.
  • Squashes provide low-level ground cover to help suppress weed growth.

Making your own three sisters garden

Ground preparation

  1. Start your three sisters garden in early spring.
  2. You will need to clear a circular plot of about 8ft to 10ft in diameter.
  3. Dig over the plot and add plenty of well-rotted manure or mushroom (or normal) compost.
  4. Mound up the soil a little (about 6 inches to a foot high in the centre).
  5. Let the ground settle for a while and hoe out any weeds that appear.

Sowing your crop

  1. Sweetcorn: During late Spring, sow a ring 8-10 Sweetcorn seeds in a center of the circle, ensuring that they are spaced correctly (see seed packet for distancing). After germination, when your sweet corn is about 10 inches high, draw up a few inches of soil around each plant to increase root growth up the stem. The will give you plants a firmer footing. You may want to add a few sticks to give the sweetcorn more support in taking the weight of the runner beans.
  2. Runner Beans: After all risks of frosts have passed, sow two beans at the foot of each sweetcorn. Once the seedlings have appeared (after about 2 weeks), remove the weaker of the two to leave a single seedling for each sweetcorn. Allow the runner beans to climb up the sweetcorn.
  3. Squashes: You can use any kind of squash – butternut, pumpkin, courgette, marrow, etc. Start your Squash seedlings in a frost free environment during April and plant around the outer edges of the mound after the risk of frost has passed. I tend to train my Squash plants around in a circle to save space.

There is little to do now, aside from ensure that you water on a regular basis, including a good organic fertiliser and check your plants for pests. Runner beans are prone to black fly and squashes – mildew.

James Middleton

An obsessive gardener since 1982. Day-time job - web designer and developer and University lecturer.

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