Posted: 28/10/2017 at 15:07
Hi Victoria, 'three sisters' is/was used by native americans and consists of growing maize (sweetcorn) climbing beans and a squash plants together. Beans have symbiotic bacteria which grow in nodules on the roots and these fix nitrogen and produce more than the bean plant needs. Sweetcorn needs lots of nitrogen so growing the two together is beneficial. The squash plants act as groundcover and keeps the roots cool in hot weather as well as keeping down weeds. Finally, the climbing beans are trained to interweave between the corn plants and this protects them from strong winds without having to stake them. I've tried it in my garden and it works! I used sweetcorn, climbing french beans and butternut squash.
In a similar vein, I grew early broad beans in between the rows of potatoes this year and had good crops of both. The beans were planted on mounds of earth between the rows and then pulled up after cropping; At that point the soil from the mounds was used to earth-up the rows of potatoes.