As our Spring crops are gradually going in, we’re making space for some sister action to take place, all three of them – corn, pumpkin and beans – together like they should be.
These three plants are a guild of plants traditionally grown in Native Amerrican agriculture. Dating back to around 5000 years, it is so successful, it’s now on of the most popular “pin ups” for companion planting around the whole world. The symbiotic relationship between these three plants is particularly wonderful, here’s how it all works.
Image from here
Traditionally grown on a market garden scale, a large amount of diverse food is harvested from a relatively small space. Image from here
Structurally, the corn does what it does best, and grows tall and straight providing the perfect climbing pole for beans to grow up. The beans provide nitrogen to the soil, being heavy feeders, both the corn and pumpkin lap this up for their own use. Meanwhile the squash (generally a type of pumpkin) sprawls in and around the base of these two plants acting as a living mulch with its big, shady leaves. It also helps suppress or slow the growth of weeds due to this pattern of growth.
Apparently corn lacks the amino acids lysine and tryptophan, which the human body needs to make proteins and niacin, but beans contain both and therefore corn and beans together provide a balanced diet. And of course, if one of the crops fail (due to pest or disease) it is ‘backed up’ by another two – so you never go hungry, clever.
If you take a look of each of these plant’s root profiles you’ll notice they all have different root ball shapes where they inhabit different levels of soil meaning they’re not competing for nutrients. So clever, so sophisticated. Image from here.
A smaller three sisters patch. Image from here.
The other great thing about this guild (there are many) is that you can plant it on any scale, so even if you have a small urban garden (like we do) you can still have a productive patch in a relatively small space. We’ve allocated a garden bed roughly 5m x 3m which will include around 16 corn and bean plants and two sprawling pumpkin plants. However we’ve also planted it in smaller beds like the one shown above.
The startings of our three sister garden, still inside – but not for much longer.
Being in a cool temperate climate, we’re yet to establish this year’s three sisters garden outside, but we thought we’d get a head start and get the corn and pumpkins going inside first. They’ll be moving outside in the next week where we’ll direct sew the beans at the base of each corn plant. When you’re planting this guild, be sure to give the corn a head start as the beans grow so fast they’ll quickly catch up to the height of the corn. If you’re in a warmer climate, you can direct sew all three seeds at the same time straight into your garden area, they’ll all go gang busters. Where ever you are, make sure your soil has LOTS of food i.e. manure, compost, as corn and pumpkin are hungry plants and require healthy, nutritious soil to thrive.
To see and learn more about the three sisters, you can watch this short video I helped make back in 2010 about companion planting that features this mighty fine guild, plus a couple of other combinations and related gardening tips.
Utilising companion planting in your urban garden or small farm is a clever approach to getting the most of the area your working with and maximising the benefits for both you, your soil and the plants. Get into it!
I’d just like to note, I grew three sisters this past year. I do not live in a desert environment, and suffered from not enough sunshine and pooled water in the beds around the mounds with all the rain. Many of the beans rotted, and similar for the squash even though the fruit were raised out of the water on pieces of wood. The corn grew okay, I guessed.
The squash vines escaped from the beds and trailed out from under the corn, up to 10 feet out. No squash amongst the corn grew, any that did were at the edges. Note that squash was planted and germinated and grew long before the corn shaded them out. Beans were planted after corn, perhaps grew up 2 feet at most, although some were dwarf varieties. Two varieties were native american (one of which was gila indian), and one was dwarf cannelini.. but no difference in height.
The corn and the squash and beans were planted on raised mounds, within the bed they were planted in. Unfortunately, the vines and fruit trailed down off these into the wetter areas, in the case of squash. The corn didn’t seem to mind the wetness.
In deserts, where sunlight is in abundance, 3 sisters would be a completely different experience. For me, I’ll be planting beans, squash and corn completely separately and won’t be interplanting.
Hi Roger,
I assume you’re in a humid/warm climate where plants need a lot more air flow around them to avoid pest/disease action. However I can still relate to some of your experiences in our cool climate, especially the sprawling pumpkins! I design for this by planting them on the edges and guiding them around the bed to do ‘one lap’ and then I direct them outside the bed to sprawl elsewhere (where they’re not in the way). I also prune them vigorously so their leaves don’t clog up the bed as even in our climate powdery mildrew can sneak in quickly in that environment.
I don’t plant on mounds as we have dry summers and it’d dry out too quickly and prune my beans otherwise they become too heavy for the corn and pull them down, sometimes snapping their stalks. So I guess the thing is to always adapt any growing technique to your climate/context, so if that means more space and/or more separation then that makes perfect sense! Good luck with your next growing season :-).
Hi, thanks for this, we have been starting the 3 sisters in our garden and I am looking forward to seeing how they go! I will stake the beans/corn if need be, we saved the seed from our beans from our last crop so I’m looking forward to seeing how they go! Thanks for the root diagram and the tips!
I have read that one can grow 3 Sisters for max 2 years followed by 8 years fallow on that soil. Is this so? Can the fallow period be reduced by organic fertiliser of some type?
Or do I need many different crop rotation sites in my garden to make sure I do not ask the soil to support 3 Sisters for more than 2 years in 8?
Hi Milpa, As it’s a diverse guild of plants we pretty relaxed about crop rotation. If space is really tight I’d suggest just making sure there’s at least one season between planting that guild in the same place again. In that off season we’ll plant a mixed green manure in there. In our garden we have approx a three year cycle before it comes back to the same garden bed.