We just planted our first bean and squash bed for this year: 41 feet long by 3 feet wide with 160 Cherokee Trail of Tears Black Bean seeds and 21 Waltham Butternut Squash transplants from our Spring seed-starting bonanza. It's a modified Three Sisters planting since we have consistently had problems with our heirloom pole beans choking out corn and other "living trellises" such as sunflowers. So this year we're trying Two Sisters.
Beans and squash in last year's garden
Interplanting, a fancy word for planting more than one thing in the same bed, makes better use of space in the garden and can also help deter pests.
Also called companion planting or polyculture, interplanting is old hat for most home gardeners, who are used to making the most of small spaces. But most food eaten in the US is produced in large-scale monoculture operations where companion planting is nowhere to be found. We're experimenting with interplanting on a scale somewhere between home garden and small farm: we'll plant 1,000 pole beans and 120 or so winter squash plants in our Two Sisters beds by the time we're done this spring.
Aside from the practical benefits of interplanting, I think it makes for a more aesthetically interesting garden. Beauty is not one of the defining characteristics of most food production in the US. But we're interested to see if we can produce a relatively large amount of food in a beautiful, lush garden more akin to a permaculture food forest than to the image of a field of row crops that comes to mind when most of us think about food production.
And more important than all of the philosophizing: we want to eat a lot of dried black beans and butternut squash (protein! beta carotene! vitamins! minerals!) all winter long. These bean and squash beds in the garden should supply plenty for us, and maybe we'll even have some to trade and sell.
In the meantime, here's a good resource on companion planting: Sloat Gardens blog post, and another: companion plant table from Urban Grange.