The "three sisters" growing technique is uncommon in the UK. Practised by native Americans to provide food through very harsh winters, it's also a method of growing three crops in harmony.
It puzzles me that so few gardeners adopt this companion planting vegetable growing method.
Sweet corn and not maize
I have been known to look enviously upon fields of maize 10 or even 12 ft high, with cobs on every stem.
My own ‘maize’ is, of course, sweet corn. It has a much higher sugar content than farmer’s silage maize. My crop will provide me with cobs but through the 'three sisters' technique, will also provide a 'sister' crop with much-needed support.
I pause to wonder what First Nation Americans would have thought of maize – this ‘corn’ on steroids?
For them, maize was a staple and one of three vital crops they grew to ensure they didn’t go hungry in the harsh long winters of North America. The Iroquois tribe is perhaps best known for using this plant combination, but many other native American peoples also practiced it.
The other sisters
The other two crops are pumpkins [squash] and beans. With sweet corn, these three make up the ‘three sisters’. I’ve successfully grown the three sisters before, sometimes on a large scale, but often with subtle variety variations.
The sweet corn bit is easy enough, and in the UK, we are fortunate in having varieties that will mature in our shorter summers. We also have varieties that have a naturally high sugar content. These, and to an extent, pumpkins and beans, would have traditionally been dried to eat in the winter.
Sowing and planting
You can sow sweet corn directly into the ground in early May. I prefer to sow mine individually in deep containers such as Rootrainers, and like to get them going in an unheated greenhouse or polytunnel. I'm always keen to get them off to a good start because I want them to be healthy and tall enough to support one of the other sisters. The tall stems of sweet corn provide the bean pole support that climbing beans need.
I plant the sweet corn out after the risk of late frost has passed. I then sow a bean seed beside each plant so that, when it germinates, it quickly climbs the sweet corn stem. Beans fix nitrogen in the soil and provide the sweet corn and pumpkins with some of the feed that they need.
Pumpkins or Squash
But pumpkins and squash are hungry beasts and need lots of nutrients to do well. So I make sure that the whole plot has plenty of well-rotted manure added before anything is planted.
N.B. Curbita maxima, pictured above, was domesticated in South America. According to world-leading expert on ancient crops Gayle J. Fritz, indigenous eastern North Americans domesticated and grew Cucurbita pepo ssp. ovifera, similar to some modern squashes. At some point before or after contact, Cucurbita pepo ssp. pepo pumpkins (like today's jack-o-lanterns) spread across eastern North America, having been domesticated thousands of years earlier in what is Central America and grown in the U.S. Southwest since 2000 BC.
It doesn’t matter whether you grow pumpkins or squash, which is closely related. While we will only eat the flesh of the fruits, the Native Americans will have almost certainly eaten the dried seeds in winter.
Choose a variety that ‘runs’ and covers the ground. This ensures that the space below the beans and sweet corn is fully utilised and the leaves and shoots smother any weeds that might try to grow down there. The big leaves will also mulch the soil and trap in valuable moisture.
Like the sweet corn, I prefer to sow my pumpkins and squash individually in containers; getting them up and away in the greenhouse before planting them out. Of course, this can also be done a bright windowsill. The pumpkins can go out at the same time as the sweet corn. They scramble around on the ground under the beans and corn. This technique maximises the yield from a small area without the three crops competing with one another.
I’m growing ‘F1 Firestorm’ beans, which are a hybrid between French and runner beans. This variety can be relied on to produce a good crop even when it’s hot and dry - conditions that runner beans don’t particularly like.
First Nation Americans would have grown a form of their native bean that was drought tolerant.
Perhaps growing those speckled pod ‘Borlotti’ beans and drying the seeds would get closer to their practice.
The beauty of this system is that there is a balance between the plants, and a balanced diet is a result. There’s some tasty recipes
based on these great beans here.
This ancient Three Sisters companion planting works as well now as it did so many years ago for the Native Americans. While it’s too late to get going this year, perhaps I have sown the seed of an idea that you might like to try next spring.
Have you had success growing the Three Sisters vegetable combination?
Do you grow a variation of the three sisters growing technique?