Retaining moisture in your garden

Moisture retention is becoming more important as the cost of water increases and the availability decreases.  Climate change is likely to exacerbate these issues. Building humus in the soil becomes the most rewarding strategy to reduce moisture loss.

Humus improves soil structure and seriously increases your moisture holding capacity, If you can increase the humus levels by just 1% then every square metre of the soil can now retain 17 litres more water.

Composting is an excellent way to build humus, but you might also consider green manure crops whenever there is a chance. When green manure is dug back into the soil, the organisms convert the organic matter into humus. My strategy is to use Instant Humus, to encourage humus production.Yes, it is a product we sell, but it works so well! 

The most successful commercial composting system in the world is called CMC composting and it has some important lessons for the home gardener as well. It has been found that the addition of  10% clay has proven to produce a form of stable humus that can continue offering benefits for up to 35 years!

If you can’t access a friable clay, then you might add some soil or Soft Rock Phosphate.

What is my zone?

So many times as a child I would witness my mother going on a trip and returning home with all types of plants and cuttings that she eagerly planted in the garden, only to watch them wither and die, or flourish until the winter frosts arrived and blackened the poor struggling plants.

Now I realise that part of my mother’s error was to fall in love in a plant that looked lovely in one climate zone, but was unsuitable for the zone where we gardened. A better understanding of the various climatic zones would have resulted in more success for my mother.

There are a number of climate zones:

• Tropical
• Subtropical and warm temperate
• Semi-arid and arid
• Dry temperate (Mediterranean)
• Temperate and cool

Each zone or climate has its own characteristics, obviously, and so will dictate what you can plant and when.

• Tropical

Distinct wet and dry seasons

Rainfall up to 4000mm per year, mostly falling during summer

An average winter daytime temperature of 30 Celsius

An average summer daytime temperature of 32 Celsius

Equal hours of daylight and darkness, regardless of season.

           

• Subtropical and warm temperate

Some distinct seasonal changes

Rainfall of up to 1200mm per year, mostly during the summer

An average winter daytime temperature of 10-20 Celsius

An average summer daytime temperature of 20-30 Celsius

Mid-winter day length minimum of 9.5 hours ( 14.5 hours of darkness)

• Semi-arid and arid

Hot days in summer and cold nights in winter

Rainfall of more than 250-500 mm per year, mostly during the summer

An average winter daytime temperature of 20-33 Celsius

An average summer daytime temperature of 34 Celsius

Mid-winter day length of 10.5 hours (13.5 hours of darkness)

• Dry temperate (Mediterranean)

Hot, dry summer

Rainfall of more than 600-800 mm per year, mostly falling in the winter

An average winter daytime temperature of 15-18 Celsius

An average summer daytime temperature of 30-33 Celsius

Mid-winter day length of 10.5 hours (13.5 hours of darkness)

• Temperate and cool

Winter frost and/or significant snowfall possible in some regions

Rainfall of more than 600-10000 mm per year, depending on latitude and distance from the coast

An average winter daytime temperature of 5 and 13 Celsius

An average summer daytime temperature of 16 and 26 Celsius

Mid-winter day length of 8.5 hours (15.5 hours of darkness)

Source: Annette McFarlane, Organic Vegetable Gardening,