After increasing your soil’s organic matter to increase water retention, mulching and using drip irrigation drastically reduces water use. But we can go a few steps further to reduce water loss. These “extra” measures make a huge difference in arid climates.
Australian permaculture guru, Geoff Lawton has a few good suggestions in his video, Permaculture Soils.
Plant in blocks
The Colorado Master Gardener program (CMGP) suggests planting in blocks rather than rows. Why? The block-planting configuration automatically shades the soil (and roots) and reduces evaporation.
The CMGP also suggests reducing the competition for water by removing weeds. If you mulch (which you should be doing in the first place), you don’t have to worry about weeding. It’s another reason to mulch!
Group plants according to their water requirements
Use the xeriscape technique of grouping plants with similar watering requirements. You will save more water this way and irrigation is a breeze. For example, cucumber, zucchinis, and squash have similar water requirements.
Windbreaks make a huge difference in a hot windy climate. Windbreaks reduce evaporation (and therefore water loss) from plants and the soil.
We’ve all heard of raised beds for vegetable and other gardening. These are ideal for climates with enough rain, and a lifesaver for gardeners growing on clay soils and/or contaminated soil.
But raised beds aren’t ideal for arid, hot climates. The soil heats up and dries up very fast.
In The Kitchen Garden segment of Permaculture Soils video, Geoff Lawton, Australian permaculture Guru, advises against using a raised bed vegetable garden in arid climates.
“Where we have very hot and dry conditions, says Lawton, “We go the other way and we’ll garden with a sunken bed. A bed that is actually opposite [to a raised bed], so that we’re retaining moisture, we retaining a cool growing condition because it’s too hot most of the time.”
In arid, sunny climates, a shade cloth would drastically reduce heating and evaporation without comprising photosynthesis. A good example of sunken bed with shade is shown in Geoff Lawton’s Permaculture Soils video.
Recap on all water-saving techniques
Paying attention to the soil is key to lower water use. It’s water smart. The techniques are low tech and low cost. It just costs you a bit of time and patience.
The soil’s condition has a dramatic effect on water use. A soil with high organic matter uses 10 times less water than soils with no or poor organic matter content.
Add a 2- to 4-inch mulch cover to reduce water evaporation. A 2-inch mulch cover reduces soil evaporation by 40 percent and a 4-inch mulch cover reduces soil evaporation loss by 50 percent.
Paying attention to the soil’s texture, and watering accordingly, reduces water waste. Water clay soils gradually to allow the moisture to slowly seep into the soil instead of running off the surface. Water clay soil deeply. Light sandy soils need watering more frequently than heavier soils (ie silt or clay), but less water can be applied at each watering.
Windbreaks are critical to reducing water loss in hot, windy climates, as are sunken beds with shade over top in arid, hot climates.
Combine these techniques with drip irrigation, and your water worries become a thing of the past.
Hope you’ve enjoyed my water reduction suggestions. If you’ve any other suggestions, please feel free to comment.
Colorado master gardener program. Water conservation in the vegetable garden
Geoff Lawton. Permaculture Soils. DVD. Eco Films 2010.