Nurture the Soil is the third principle and a cornerstone of Bay Friendly practices… based on the theory that feeding the soil, not the plant, encourages a thriving food-web of microorganism, worms and other beneficial creatures. Healthy, living soil teems with all kinds of bacteria, worms and other organisms that carry out these crucial actions:
Build soil structure;
Store and cycle nutrients;
Protect plants from pests;
Improve water infiltration and storage;
Filter out urban pollutants.
Before and during any construction or garden renovations, always follow these procedures:
1 - Protect the topsoil, typically the first few inches of soil, which nurtures a plants ‘feeder roots.’ Topsoil is a valuable resource that often is removed or mixed with subsoil during construction; conserving it can reduce many problems over the long run and minimize fertilizer and irrigation requirements.
2 - Protect soil from compaction: heavy equipment can compact soil down to 2 feet below the surface. Compacted soils don’t have adequate space for air or water; avoid walking on and working in soil that is too wet or too dry.
3 – Defend against erosion: during construction, prevent loss of soil by storm-water runoff or wind … stock-pile and cover topsoil for reuse. On steep slopes, create terraces; and don’t remove valuable trees or shrubs, which help to prevent erosion, and protect them with fencing.
4 – Amend soil with compost before planting: Compost improves problem soils, especially those that are compacted, heavy clay or sandy, or lead contaminated. For trees and shrubs, amend the entire planting bed or dig planting holes no deeper than the root ball and a minimum of 3 times the size of the new plant’s root ball. Rough up the sides of the hole and mix soil compost into soil, then backfill. If possible use compost made from local green and food waste.
5 – Grasscycle: if you still have lawn, leave the clippings on the lawn after mowing, except when grass is too wet or too long. Clippings can meet some of the lawn’s nitrogen needs and supply other nutrients as well.
6 – Mulch regularly: organic materials - bark chips, composted green waste, leaves, etc – supply nutrients. Maintain 2-4 inches of organic mulch over the soil surface at all times; this helps to conserve water, suppress weed growth, provide nutrients that enhance growth and make the garden look clean and fresh!
• See article below ‘ Sheet Mulching.
7 – Aerate compacted soils: one easy way is to use power augers or water jets to create holes in compacted soil around trees and shrubs and fill with compost. For turf/sod, top-dressing with compost after aerating in spring is best.
8 – Naturally feed soil: Apply compost each spring and fall either with compost tea (see links following) or by top-dressing; this means spreading compost around the base of the plant and letting it work its way into the planting bed, then replace the mulch. For information on compost tea, check www.composttea.org or www.soilfoodweb.com.
9 – Avoid synthetic, quick release fertilizers: a plant’s nutrient requirements are best met with compost, naturally derived fertilizers or slow-release fertilizer – only if your plant really needs nourishing.
10 – Avoid or at least Minimize Chemical Pesticides: some can be toxic to soil dwelling creatures such as earthworms. Minimizing pesticides reduces water pollution and helps support soil life.
Next time, we’ll focus on conserving water, a huge issue throughout California.