The following excerpt is fromCompost Science for nurseryman : Simple Methods for Nutrient - Rich Soil(New Society Publishers , January 2023 ) by Robert Pavlis .
Keyhole gardening is both acompostingmethod and a horticulture method . I am fit to trace the more traditional purpose of this method so you understand the whole construct , and then I ’ll describe some variations that are easier to use .
The whole affair begin by building a special keyhole garden which is a circularraised bedthat contains a center compost field . One side of the circle has a pie - slice cut out of it so that you could reach the inwardness . I guess the term “ keyhole ” comes from this shape , but I do n’t really see a keyhole ?
If you Google keyhole garden , you will rule many different designs for such a garden . The raised seam can be any pinnacle , and the wall can be made out of any material , include rocks , bricks or even woods . It does not even have to be a circle . It could be a square with one side indented to earmark accession . The garden can also be domed with the center in high spirits than the walls .
The center composting sphere is some type of cylinder or John Cage that can hold cloth . I have seen people use wire mesh , steel drum , and charge card buckets . The requirement here is that the bottom is leave undefendable so the compost pose on soil , and the side should have lots of hole to allow soil organisms access to the constitutional affair .
This designing is fundamentally a garden build around a compost John Milton Cage Jr. . New organic matter is bring into the top of the batting cage as you collect it . It slowly moves down as old material decomposes . Nutrientsleach out the side into the garden , and macroorganisms can move from the soil into the compost for a snack . The John Cage itself is either never emptied or only emptied every few years .
This composting process is quite simple , but making the garden is more study . There are way of life to simplify the system and still retain most of its benefits . The raise layer can be only a few inch gamey and made with a unmarried run-in of brick . The center compost pit would ask to be lowered so compost happens below mark .
Keyhole horticulture will also materialize even if the garden bed is not raised , or raised a few inches with no wall around it . The chief point is to have a garden all the manner around the composting pit so that the whole garden benefits from leached nutrient .
This is an interesting musical theme , but I retrieve it has some fundamental flaw . The title is that nutrients flux from inside the cage into the surround grease . Although this will hap to some extent , most nutrients move down in soil , not sideways . Plant root experience mostly in the top 6 inches of stain . That mean plants wo n’t get most of the food .
report that I have seen show plant life doing equally well over the whole garden , but you would expect the single near the heart to do much well if they were begin food from the compost , so I mistrust the plants are catch their nutrient mostly from the original land and not from the compost .
raise beds dry out out quicker and therefore require more watering .
If you would care to build one of these garden , consider building it very close to grade and do n’t raise it up more than 6 inches . The compost cage in the center should be placed at grade so most of the cloth is above the garden , and it should have a solid bottom . These changes will reduce watering requirements and increase the nutrients that make it to plants .
