To hugelkultur or not to hugelkultur? Mulch is the question @ Rahma Forest Garden

Rahma Forest Garden is likely home to some of the most carbon-rich soils in the City of Syracuse. Trees and perennial plants have been established there for almost 10 years, and many truck loads of mulch have been spread on the site with Syracuse Grows’ annual garden Resource Drive. We chop and drop some plants like black locust (Robinia pseudoacacia) and comfrey (Symphytum) to help build soil carbon & nitrogen. In addition to chop & dropping some plants, we accumulate a lot of plant matter from weeding, thinning, and pruning on site, which gets piled up in a low pallet fence roughly separating woody debris from green materials. Our carbon accumulation is in need of problem solving however, and strategies for handling yard waste have become a point of debate.

The piled up plant debris is useful in theory, as it could decompose and become a soil amendment for the garden. In reality, the piles are too loosely stacked to effectively break down, they are unwieldy to move or turn over, and they ultimately end up an eye sore (or once upon a time, a nest for abandoned kittens!) Occasionally, we need to empty the piles out by bringing them to the curb for city pickup.

Mulch from Syracuse Grows, waiting to be spread with pitch forks & shovels, buckets & wheelbarrows at Rahma Forest Garden September 22, 2018

City pickup is a nice option as the city has substantial mulching infrastructure & logistics, and the mulch made from city yard waste like ours is available for pickup at various locations for free. We end up cycling nutrients from Rahma Forest Garden, to the city composting facilities, then back to Rahma Forest Garden to some extent! Taking a closer look at this nutrient cycle, city pickup means the use of fossil fuels (trucks, heavy machinery) and the removal of nutrients from on the garden. That yard waste grew from sun, water and soil. If the goal is to build soil with a low-footprint as part of this regenerative garden, isn’t there a more regenerative solution that uses less fossil fuels? Some options being considered are listed below. The question at hand is: what’s the best way(s) to handle plant waste from the forest garden, maintaining healthy nutrient cycles for the site and beyond?

  • Hugelkultur (the rest of this post explores this in more detail),
  • Chipping small diameter woody debris, using the chips immediately or piling chips up to decay and become mulch, and/or
  • Setup a denser compost pile with shorter-length and taller-height walls, so plant matter can be packed in and piled up enough to decompose well.

Hugelkultur is a promising but controversial option. Hugelkultur is a German word for “mound culture”, and it refers to the technique of building mounds using a core of woody debris (e.g. thinned and pruned wood) and an outer layer of compostable biomass (e.g. weeds). These mounds – known as “hugels” – can be an eye sore at first for neighbors unfamiliar with the method. Hugels can appear to take up space, though in a year or two it becomes clear that hugels become fertile garden beds. Even if we fully embrace hugels, this forest garden will continue to generate an excess of plant matter and so we’ll still need to continue using city pickups. With these considerations in mind, this is one of many cases where social dynamics are an integral part of permaculture design, especially for a community forest garden: the aesthetic of the garden and opinions of neighbors is an important part of the garden’s value and success over time.

In discussing this topic, we recognize that there is no single correct answer. We’ll try to use all the tools in our toolbox (chop & drop, city pickups, hugelkultur, our compost pile) and may add new tools too (a wood chipper, an upgraded compost systems). Do you practice any of these methods, and if so what pros & cons do you see? Do you have any tips for nutrient management at Rahma Forest Garden?

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