We planted a square foot garden version of the 3 Sisters Garden on Labor Day, September 24, 2010. Here is the planting grid. B = Beans, C = Corn, and S= Squash. Plant corn first. 2 weeks later plant beans. They will use the corn as a trellis. 2 weeks later plant squash. This time you will let the squash meander on the ground instead of growing it vertically. It will help keep moisture in the soil.