Good soil is rich in organic matter. Powdered fertilizer might provide the chemicals needed for plant growth, but can’t improve structure in the way compost does: holding water, providing pathways for roots, slow-release nutrients, and food for worms which aerate the soil.
Good soil is alive: Not just with worms, but with a million creatures invisible to the naked eye: bacteria, yeasts, fungi, actinomycetes and other microbes. These creatures all interact with plants to create a healthy rhizosphere (root zone).
Good soil holds moisture: Compost can hold up to 20% water without becoming waterlogged, so a 10cm layer of compost on your beds is like having a 2cm deep pool of water.
Six things you can do for your soil over winter:
- Grow broad beans: they can get nitrogen from the air and convert it into plant material. Plus you get a crop in spring!
- Trenching is the simplest form of composting: dig a trench, at least a spade’s depth, across your bed. Add vegetable scraps as you get them, covering with soil as you go. Things planted on top of the covered trench will have all that food at their roots
- Pile seaweed across the bed (or around fruit trees) and let it rot down. Lots of nutrients and no weeds!
- Collect up autumn leaves and grass clippings to build a compost heap on top of the area where you are going to grow next year’s tomatoes: Come October, just collapse the heap sideways and plant on in.
- Sprinkle seed: Green manures such as lupins, oats and mustard can be dug in or used as mulch.
- Cover with mulch: Arborist’s chip is a cheap and long-lasting way to keep away weeds, feed worms and build soil.
The Council Green Gardener, Hannah Zwartz, offers sustainable and waterwise gardening advice to local residents, community groups and schools.
Community Visits and workshops are free.
To contact the Greener Gardener, call the Council on 296 4700 or 0800 486 486 or see www.kapiticoast.govt.nz/greenservices