This Three Sisters history could be a blog related to the National Sibling Day which is held in some of the states in the USA.
And it sort of is, in so far as seeing Sibling Day mentioned when I was meandering around the internet reminded me that I needed to write another blog on specific cultivation techniques.
The first and more general Growing Methods for Gardeners article did promise to look at each type of gardening.
So here we are, with National Sibling Day on April 10th, tying in nicely with the start of the growing season and this historical cultivation method.
The Three Sisters History
These three food crops have all been around for thousands of years. But it’s virtually impossible to give a definite time when they started to be grown together as common practice. Its probable that it dates from around 3500 years ago in Mesoamerica. This is the area of the Americas roughly covering Mexico down to Costa Rica.
As Maize, beans and squash are not indigenous plant species to North America, it seems likely that they were brought to the northern regions by migrants from Mesoamerica. There is archaeological evidence of the three sisters cultivation in North America, in what is now Virginia, by about 500 AD.
The likelihood is that it arrived before this, but arable crops don’t leave as much evidence as stone buildings! Archaeology is better at showing the seeds of the crops in the compost heaps of settlements than it is at proving they were grown together in the fields. By AD 1300 it had become a crucial part of the Native Americans’ agricultural system.
What is certain is that once Europeans arrived, their habit of written records allows us to track the situation as it was then. For example, de Soto, found Native Americans growing crops, specifically Three Sisters system of agriculture, from the Florida peninsula to the western part of Arkansas. De Soto was a Spanish explorer who led the first expedition north from Peru and Mexico into the modern-day USA.
Individually the three crops have been around for longer than they have been as a triad. Beans were the first of the three to be cultivated in South America, at about 10,000 years ago, but didn’t appear in Central America for about 3,000 years after that. Maize was domesticated in Central America roughly 9,000 years ago, Squash a millennia earlier.
Three Sisters History and Benefits
This growing method utilises some of the properties of each of the individual plants so that they all benefit.
Often described as an intercropping method of cultivation, the plants form more of a symbiotic relationship than most intercropped edible plants.
The Maize grows tall and provides a support for the climbing bean. Both these plants provide shade for the hot noonday sun for the squash below. Maize is a nitrogen hungry crop. Beans are leguminous plants, able to ‘fix nitrogen’, accessing atmospheric nitrogen and making it available in the soil to the other plants. the squash with its large leaves keeps the soil moist and reduces competition from weeds.
That nitrogen seeped into the soil by the beans benefits the soil and the following year’s crops. By growing them together, some of the reasons for following a system of crop rotation are negated. So it is possible to grow these same crops for a number of years in the same place without there being a detrimental effect.
Together, the three sisters crops produce more protein and carbohydrates for us humans when we harvest them, than they would if grown as three separate monocultures. Up to 20% more depending which research paper you read. Not bad, eh?
Three Sisters – or Four Sisters?
And it gets better. In some areas, Mexico being one of these, there is a tradition of growing four sisters together, rather than three.
Sister number four is Cleome serrulate, Rocky Mountain bee plant. As it’s name suggests, it has a nectar rich flower, much loved by pollinating insects. So by including the Cleome, the pollination of the bean and squash plants is guaranteed, and fruit follows flower. The corn is wind pollinated so not part of this equation.
Regularly found near ancient settlements, the bee plant is an obvious plant inclusion into the quartet. Well, its obvious to us now, as we understand about pollination. I suppose the question is, would this sibling relationship have been obvious, even if not fully understood, thousands of years ago? To which the answer is why not? Observation, if only for a few minutes, means we know the bees fly from one flower to the next. Come the harvest, if more crops are produced from the areas with Cleome flowers, there will, over a few years, be the putting together of the action and the consequence.
The Rocky Mountain bee plant is not the only flower with a claim to being the fourth sister. Sunflowers, Helianthus annuus, have also been suggested. However, there is a problem as Sunflowers are allelopathic, ie they produce enzymes which dissuade some other plants from growing nearby and can affect the setting of fruit. Monarda, Bergamot, bee balm has also been mentioned. Although a pollinator friendly plant, it has not been found in archaeological sites so historically unlikely. But there’s no reason why it shouldn’t be a 21st century pollinator for your own three sisters cropping system.
If you’d like help getting your own Three Sisters growing system in place, why not ask about Plews Gardening Lessons?
We have full Edible Gardens courses on offer. But if you’re reasonably confident about growing your own vegetables and would just like some help to get started a half-day session in your own garden with our expert gardening teacher may be just what you need!