In our PDC (permaculture design course) in Raktamachat, Thailand, we spent the morning making a banana circle mini food forest right in our kitchen garden.
Banana circles are a design used in permaculture to produce lots of food in a small space using recycled grey water (water from the kitchen sink or shower, pipes, run-off and overflow water) with the convenience of having only one place to add inputs (water, fertilizer, compost etc) while feeding several plants and crops.
Bananas are used because they are very heavy feeders and need lots of water and so are a perfect choice in Thailand. It is possible to substitute with similar plants more suited to your local climate. Banana circles can filter soap, detergent residues and oils found in grey water but avoid harsh chemicals and make smart choices about household products.
Using your two meter circle, dig out a dish-shaped (concave) hole to a depth of ½ to one meter. Put the soil from the hole around the edge to create a mounded garden bed. At this point, you can make an opening at ground level for rainwater run-off to enter the banana circle.
Line the hole with paper, cardboard, or a few layers of banana leaves to slow down the infiltration of water later. This will make sure that water and nutrients hang around long enough to be taken up by bananas, papayas and other plants that surround the pit.
Plant banana suckers around the rim of the mound at 60cm intervals. We use four banana suckers around a two meter banana circle. These can initially be inter-planted with papayas. Also add cover crops like watermelon, taro, pumpkin, sweet potato etc. Comfrey and other green manure crops can be inter-planted and chopped into the mound. You can also add climbers and vines like passion fruit when the trees can support them. Think layers, guilds and stacking food! We planted lots of watermelons as a ground-cover crop and lemon grass to keep the mozzies away and keep our kitchen smelling good and will keep adding.
Mulch very generously to cover and protect the soil and minimize evaporation.
We have a Rakin’ mulch delivery system!
Water thoroughly and keep watering until the banana circle starts receiving the grey water.