Last post, I talked about a permaculture food forest and how to establish a system that’s interconnected and self supporting. One thing I didn’t talk about is how to make the system as care free as possible. Who wants to continually apply fertilizer or pesticides – even if they’re organic?
All plants need nitrogen, phosphorus and potassium. A good bag of organic balanced fertilizer that contains all three elements can cost (in our area) up to eleven bucks for a three and a half pound bag. Yikes! In permaculture, the goal is to add elements to the overall garden/landscape so the plants feed themselves. But let’s talk about nitrogen in particular. Plants need adequate nitrogen to convert sunlight to growth. How do we supply nitrogen to our permaculture food forest without adding something from a bag?
We add plants that fix nitrogen in the soil. Now, let me just clarify that – at the very start of your food forest – you may have to add fertilizers (preferably organic ones) until the plants are established and self supporting. But the goal is to eventually get off the bagged stuff.
There are many trees and plants that supply nitrogen. Putting an adequate number of those in your landscape will solve the nitrogen problem. In our little half acre, there’s not enough room for nitrogen fixing trees so we’ll be using other plants. A few that supply nitrogen are Goumi Berry, Balsamroot, Groundnut, Groundplum (or, more commonly, Milkvetch), Lupine, Sweet Vetch, Comfrey and legumes. These are only a few and you should do your research before choosing your nitrogen-fixers. Some of the best nitrogen fixers are invasive species in certain areas and they should not be planted in your permaculture food forest. A list of invasive species for each state can be found online, including one for us here in North Carolina.
In our first food forest area (see previous post) I’ll be interspersing some of the above into the landscape to provide nitrogen for the plants that I want to feed. Where ever possible, we’ll be choosing those plants which stack functions; meaning plants that serve multiple purposes. American groundnut produces edible tubers, flowers and seeds in addition to being a nitrogen-fixer for other plants. Goumi berries are loved by birds and wildlife as well as humans. Balsamroot is edible. You get the idea. We’ll also be using the juglone tolerant plants closer to the walnut tree and put the non juglone tolerant plants further away on the borders of the food forest.
Another great nitrogen fixer is Comfrey. Although my research doesn’t show that Comfrey will tolerate the juglone from the walnut tree, we can grow it in a nearby location and then “chop and drop” its leaves in the food forest to add nitrogen to the soil. That’s the plan at least. We’ll see how it goes –
