This post is continued from Part 1.
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We started out talking about how to use permaculture to make our lives better, if we’re living in the drylands.
Now we continue with more techniques to cope with the dry heat (and cold).
As plants get hotter, they must use transpiration (the plant equivalent of sweating) to keep themselves cool. This uses up water, and means the plant is not growing as fast.
Then the hotter it gets, the worse this condition becomes, until it’s not growing at all.
For plants, keeping the roots cool with mulch or shade prevents much of the heat damage. So this also helps plants grow more.
Different crops have different tolerances for heat. Brassicas, peas and most greens like it cooler than do crops like corn/maize and beans.
People also benefit from not getting too hot, you know!
If you can create or harness cooling winds, you will be much more comfortable.
In the Middle East and around the Mediterranean, historically houses used chimneys facing towards the prevailing winds. These “wind tunnels” catch and funnel cooler airflow into houses.
The same technique can also be used for cooling animals and plants.
Plants grow better, people are happier 😉
What are they good for? Absolutely…everything?
No, but quite a bit!
- Blocking wind
- Creating food growing microclimates
- Slowing down dust and debris
- Hiding ugly neighbors…land
Berms will slow down the wind speed and make wind-blown nutrients fall. This can increase the fertility of your land.
It will also reduce evaporation from drying winds.
It’s possible to make your berm a hugelkultur mound as well. Then grow food on this berm, and use it for wind reduction.
A protected, moist microclimate can be created by making a berm. And you can grow more delicate plants with this method.
Also, if you have a view of the neighbors junkyard or a nearby busy road, use a berm to hide the unwanted noise and sights.
Stacking functions is a good thing!
You may know that dirt, stone, or water can store heat.
But do you realize they also store cold AKA lack of heat?
Many old cultures (China, Middle East) in hot climates use the media above for storage of coolness.
John Hait’s book Passive Annual Heat Storage talks about heat/cool storage, and ways to almost eliminate the need for heating and cooling. And Paul Wheaton’s WOFATI design borrows heavily from this book.
Some passive solar heating systems use the sun to heat water, which is stored until needed.
Then it’s released to heat the area.
This idea can also be reversed to cool an area.
Greenhouses can also be heated this way, and allow a longer growing season.
Combining a greenhouse with aquaponics (water can store a lot of heat) is a great way to produce food for much of the year, if not year round.
Passive solar houses use tile or brick strategically placed to catch winter sun and reduce fuel costs. The heat then seeps out when it gets cooler.
Traditionally, some Middle eastern cultures used porous clay pots filled with water.
These were placed where wind evaporated the water and cooled the air. It was the original swamp cooler.
As I said before, you can design wind scoops to channel air for cooling.
Also, use the natural properties of heat. Heat wants to go up, and cool air wants to fall.
Put in low shaded intake vents, high outlet vents, and let it pull cool air into the house. You could also install a solar or mains powered fan to help the air along.
Now let’s think about solar orientation. To limit heat gain, put a minimum amount of house exposed to the south and southwest (assuming northern hemisphere).
Make the house longer along the north/south axis.
This needs to be adjusted depending on how hot and cold your climate is. If you need solar gain in the winter, don’t make the house too short on the east/west axis!
You can also integrate some thermal mass to store cold, and use air openings for natural cooling and ventilation.
Earth tubes AKA ground coupled or earth-air heat exchanger, are another great way to lower house utility costs.
It uses the mostly stable temperature of the earth to put heat into, or get heat out of the earth.
It doesn’t require pumps or compressors, just blower fans to move the air. So it doesn’t use much power, and could be run with a small solar setup.
Earth tube systems can also be completely automated with very simple electronics. See this Geoff Lawton interview about a Canadian geo-solar greenhouse.
And check out this passive solar greenhouse from my favorite urban farmer, Curtis Stone.
Waffle gardens & Zai farming
Southwest American Indians, specifically the Zuni culture in New Mexico, had a unique method of growing crops in dry areas.
They made a “waffle garden” with deep pockets where crops were planted with beans and squash.
This conserved water and prevented wind erosion and evaporation, as well as catching some nutrients.
The waffle garden relied on caught rainwater or was hand watered, and it acts like a pond or dam to keep the water in place.
For more info on this method, see the article and video here.
Similar to waffle gardens is the zai farming method.
This is a traditional West African growing idea that was reintroduced to Africa in the 1980’s. It uses deep conical garden pits with compost and manure to last through dry spells.
As I talked about in Part 1, handling water properly is really important in drylands.
Drylands areas tend to get much of the annual water from large rain events at the same time of year. So we have to be able to handle large volumes of water quickly, and make it last for the rest of the year.
We do need to prevent erosion and damage to people, animals and structures.
But being able to harvest rainwater for domestic use could be an even more important skill to know.
Here in Western Colorado, it’s not uncommon to go for a month or more without any rain. And certainly no dew drop!
And then we’ll get one or two storms with little moisture, and more dry spells after it.
Some people who live off-grid can harvest all the water they need from rainwater!
For tons of great rainwater harvesting info, see the books by Brad Lancaster:
- Rainwater Harvesting for Drylands and Beyond, Volume 1, 2nd Edition
- Rainwater Harvesting for Drylands and Beyond (Vol. 2)
We talked about many strategies and techniques for drylands success in the last two posts.
- Cooling airflow
- Thermal mass
- Home design
- Zai farming & waffle gardens
- Water harvesting
Ultimately, it comes down to anti-evaporation strategies. You need to keep as much water as long as possible in the right locations.
Keep it away from sun and wind, and use thermal mass to store cold where possible.
OK, that’s all folks! Do you have any questions or comments about drylands permaculture techniques? Ask your question down below and let’s talk! You can also use the contact form, or email me at info at thepermaculture dot life.
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