USING ORGANIC MATTER TO BUILD THE BASE

 

(1) The starting point - lawn with shallow topsoil. (2) Layers built up and mulched. (3) Organic matter breaking down showing mycelium growth. (4) Same area only 6 months after planting. 

The importance of a solid base should never be underestimated. This goes for most contexts and can include anything from knowledge to fitness. Also, in the case of living systems the base is of supreme importance. A tonne of funds can be spent on plants only to find that few things thrive or that a high level of maintenance is required to make plants survive. Generally challenges for a site have something to do with the soil. Whatever space is taken over for the budding gardener or permaculturist, modern practises have generally left spaces worse for wear. Lifestyle blocks may be subdivided sections from hard run large scale commercial operations and suburban neighbourhoods are built on bulldozed land where any attention to a decent layer of productive topsoil is a long abandoned afterthought. Finally, in some cases the type or quality of soil may not be "bad" but just not as great as it could be. With these issues at hand, restoration and improvement requires attention to soil development.

Soil issues may present itself in a range of forms and include poor structure, issues with drainage and/or water retention, poor soil life, imbalanced/poor nutrient levels. Solving these issues may in some cases include an element of earthworks, however, often the answer can be found in using organic matter to build up the soil. Organic matter yields key benefits; it works as water storage, keeping water available, but without pooling. Further, it creates a supportive environment for microbiology and mycelium/fungi, which supports plant health. There are various ways of approaching the integration of organic matter; following shows one example of how this can be done. Issues to address on this site included a shallow layer of topsoil with poor structure and a dense clay layer underneath. This meant the area to be planted completely dries out in summer, but pooling of water occur in winter. Further, soil structure was relatively poor. Earthworks were considered, however, a slight slope exists in the area, which means that while the water pools somewhat, the contours don't result in significant damming.

Before the project could commence some thought to resource acquisition was required. Part of the objectives set out at the start of the project was to source from the property, within the community, and/or trade for products, as far as possible. In addition to contributing to sustainability, good planning and creative sourcing significantly reduced costs for the project.

The required materials listed below were obtained; 

• Bamboo sticks and wooden stakes (Some bought, already had a few).

• Gypsum (CaSO4 – 2H2O Calcium Sulphate) (Bought)

• Untreated sawdust/ Wood shavings (Free. Sourced from local sawmill)

• Cardboard (optional) (Free. Sourced from various sources)

• Logs and branches (Free. Sourced from property & local community) 

• Hay (Free. Sourced from a lovely local community member. Hay had too many thistles for horses).

• Horse/ cow manure - avoid collecting from animals just drenched (Free - friend's property).

• Plant based food scraps (Generated from general living).

• Grass clippings (Free. Sourced from property and neighbours).

• Compost, part processed/ soil. (Mostly purchased. Some from local community).

• Mulch (Free. Sourced from local community).

With all sourced, it was time to start the process. First digging down to the clay layer, apply gypsum and water it in. Gypsum (CaSO4 – 2H2O Calcium Sulphate) breaks up heavy clay soils via flocculation. Gypsum forms a bond with clay minerals to encourage the formation of small soil crumbs. This provides more pore space so that water, oxygen, dissolved nutrients and roots can penetrate the soil more easily. The long term changes in structure enables excess water to drain more effectively -  and in dry months enables the soil to retain more water. (No change in soil pH occur through this application).

Next untreated wood shavings were applied in able amounts. These hold moisture and will in time break down and encourage mycelium growth. Initially, they also do a great job of suppressing plant growth, providing an alternative to cardboard. I prefer this approach and tend to limit the use of cardboard to the bottom layers for paths and unplanted areas.

Logs and branches were placed on top of the wood shavings, essentially forming the core of a mini hugelkultur. The next parts consisted of building up multiple, alternating, layers of green plant material, hay and horse manure. At the top, in spaces to be planted, compost and soil was integrated. 

The process. Gypsum application to exposed clay surface. Integrating logs and branches. Alternating layers of hay, horse manure, grass clipping and mainly plant based scraps.

Some aspects exist for consideration with this type of build. Carbon to nitrogen ratio is a much discussed factor with regard to planting in materials not yet broken down. Essentially the concern is that limited Nitrogen will be available to support plant growth and will instead be utilised by microorganisms in the breakdown process. However, with some consideration to what is planted, nature seems to find a way, in my experience. In a newly established wildflower bay over sawdust and thin no dig layers, sunflowers grew quite happily to their 2 m potential and became the Autumn's crop'n'drop. If things are going to be a problem, plants will soon let you know by showing sign of deficiency and/or poor growth. If any doubt, start small and accept feedback, as per permaculture principles. Another related factor is to what extent logs, branches and wood shaving are integrated. Some suggest that integrating too much wooden material can create imbalances and excessive fungi growth. It possibly could, but again it hasn't show to be a problem in this case.

(1) Sunflowers growing into non-composted material. (2) Mycelium growth on mulch/ organic matter 

Other considerations; how much to build up and should fungi integration be kickstarted? Build up MUCH more than you think you need. As layers start to break down, piles will shrink to about ½ to ⅓ of original height. In that regard, gather so much more than you think you need. Do one mini test hugel and it will soon be revealed just how much is required :)

For a fungi kickstart, mycelium products exist that can be mixed into soil/ material. I did try one product, which was generally mixed into the material for some areas, however, there isn't much visual difference on "treated"and "untreated" areas at this stage.

(1) Site marked up, gypsum and wood shavings applied  (2)  Part way through build. (3) Ready to plant.  

With the base complete next to the fun of planting. More details on this in following posts, but a few photos for inspiration below.  

Left: The site just after planting - pre mulch.                Right: The site in Spring a few month later. 

The site in Autumn, only 7 months after planting. Starting to feel like a mini forest!