A soil building plan

Let’s learn a bit about soil building. Here’s some advice from growers, plus what I am doing in my garden to build soil.

Here are some tips from Kai Lange, biodynamic practitioner, from the Global Gardens blog.

Build soil fertility in a number of ways:

Avoiding digging (use a fork or broad-fork instead to open up the soil and a hoe to develop a fine tilth on the surface);

Using green manures (we like Phacelia, Crimson and White clover and Fava beans).

Composting kitchen waste (all raw fruit and vegetable peelings, coffee, tea and egg shells) and garden waste (have a separate compost heap for perennial weeds).

Mulching – whether green manures that have been hoed in, leaves, wood chip or straw.

Adding compost, mulch and green manures into the soil can help feed the life in the soil.

Liquid fertilisers (like nettle and comfrey tea) can help plants too but they should be viewed more as a medicinal tonic rather than a food source for plants. Making plants struggle a little, so that they stretch out their roots in search of more nutrition in the soil produces healthier plants.

In her book Edible Perennials, Anni Kelsey recommends:

Retain a permanently planted layer at all times, using ground covers between larger plants. I would rather allow a few uninvited guests (weeds) to live a while (in effect acting as a green manure) than leave exposed soil.

Allow plant material to accumulate on the soil to maintain a permanent litter layer covering the soil surface.

To seek and absorb vital minerals from the soil and subsoil and concentrate these in plant tissues use deep rooted mineral accumulator plants such as comfrey, dandelion (yes I did say that), and wild chicory.

To absorb atmospheric nitrogen (for use by bacteria living symbiotically on the root system) plant leguminous plants such as clover and alfalfa, or use annual beans – broad / runner / French or wild plants such as vetches.

Apart from gently planting new plants and equally gently removing root vegetables do not dig – it kills soil organisms.

Do not add chemical fertilisers – they kill soil organisms.

Do not walk on the soil, keep to pathways – compaction drives air out.

Build up the depth of soil over time – as more mulch material is added to the top this will naturally happen. My observation is that plants are increasingly productive as the soil becomes deeper.

Actions to build soil in the gardens:

In his book Gaia’s Garden, Toby Hemenway states that soil building techniques break down into three broad categories: composts, mulches, and cover crops.

1. Compost

Adding layers of compost around existing plants can give soil a boost. I’m growing a lot of the plants in pots and I’ve been wondering how to keep the soil healthy. Katie Rushworth was on Titchmarshes’ Grow Your Own on the telly, she suggested scraping off a layer of compost and replacing with fresh. I’ll also make the fresh compost more potent by adding seaweed to it before adding.

At the moment we have one Dalek composter in the front garden which we add to slowly as we make veg waste in the kitchen. In our small urban garden this is all we have room for. I’ll probably add another once it’s full. I’ll also start a small compost of perennial weeds in a bucket with holes in the bottom and a cover to keep out light.

For the time being, I’m buying in the best compost I can find locally (Fertile Fibre).

2. Mulches

Sheet mulching – for bare soil. I’ll likely add a thin layer of sheet mulch on areas of the garden that I’m reclaiming from grass. The soil in the ground is ever so full of stones and rubble. I’m going to need to do some work to remove a good amount of it before planting. A sheet mulch for a couple of months in the autumn after sieving might be a good way to rest and rebalance the soil after this disturbance.

3. Cover crops

I’ll grow cover crops in the raised beds over winter; fava bean, clover, phacelia etc. I’ve seen you can get cover crop seed mix.