Swales Bring Life to Your Soil

Everyone knows water means life, but not everyone pays attention to the amount of water going to your soil. Dirt, soil or earth, whatever you call it, is a living being. Having a consistent amount of moisture in your soil guarantees that it stays alive. Water is the “solvent of life” that functions in transport of nutrients through plants and is used in the energy producing-processes of plants. However, watering plants isn’t an easy task as there are a number of considerations when deciding how often and when to water your plants.

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I don’t like to water my plants for a bunch of reasons (leaching of nutrients, conserving water, wasted time, ect.). Some of the reasons I love swales include:

1. They slow down the water runoff.
2. It’s a perfect way to catch and hold water where you need it.
3. It catches vital nutrients that would have been carried off.
4. It saves time because you don’t have to water.
5. Your well stays full.
6. Save money (for those that pay for water)
7. Using town water may kill off some biodiversity with the added chlorine.

Swales are basically a way to catch water and direct it to where you need it. If you have a parcel of land with a slope, water will just run over the soil in most cases and won’t have the chance it needs to absorb water. You put an indention into the soil to catch that water or slow it down. Swales look like the letter “u” to hold the water or they can be “s” shaped to slow it down and spread it out.

The design you use will be unique to your land and needs. The depth, size, shape, angle and type of soil are all variables you need to consider. You may even have to alter your design after it’s made to get the effect you want. The one suggestion I have for you is do not try and fight nature. Work with it. My first swale was blown apart by a down pour and I had to start from scratch. It was a good learning experience, but heartbreaking!

Some people are lucky enough to have a spring or body of water that can be diverted and turned on/off as needed to flood the swales. Others like myself will focus on rain water. Always use the easiest, most natural tools you have.

The first part of your plan is to make a map of your land and plan out where you will have your trees and plants. If you plan on using mounds or Hugles, it should all be figured out first. Using wood buried in trenches (Hugles) will help hold water longer than soil.

For plants that like more water, plant where the swales hold the most water. Other plants or trees that like less water should be planted above the areas that hold the most water. The areas that hold the most water will also be the most fertile because they catch all the fertile run off.

One of my favorite parts of using swales is that every winter my rocky soil breaks down. When I first moved to this homestead my soil was impossible to work. I don’t till at all so I need a way to handle my rocky soil. What I have noticed over the years is that having moisture in the soil breaks down rock. Have you ever put a soda or beer in the freezer and it exploded? That’s what happens to rock.

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Rocks will absorb moisture and then freeze and fracture. This process happens over and over until your soil improves. This only works if you have the right moisture available in the soil. Most rocky soils are compacted and extremely dry. Conditions like this won’t allow rain to penetrate the soil and just perpetuates the situation. In order to cure this, moisture has to be held long enough to penetrate the earth. This is where swales will improve your land over time.

So let’s get to methods of making swales. My preferred method is to dig a trench 3’ deep to my planned design. Use a garden hose to layout your plan. Then, pack in wood, wood chips, safe biodegradables like grass, compost, etc. After that, cover it back up with the soil you removed. Pack it, but don’t compact it too much because compact soil doesn’t absorb water and roots will have a harder time growing through it.

I like to seed the mound with radishes, kale, carrots, endive, calendula and mums. I don’t even pick them at the start, I just use them to get a root system. Spreading some mycelium from edible mushrooms like stropharia will help break down matter and build a strong soil structure because of the spreading of the mycelium. If you’re like me, you won’t mind having some edible mushrooms to pick.

The second way you can make swales is just by terracing which is very similar to terraced vineyards and rice farms in Asia. This style of swale works well when you have steep banks. Cut into your bank to make flat areas and then put a basin in each terrace. You will need a plan to allow the water from one terrace to leak into the next terrace. The way you do this is dependent on the amount of flow going through the system.

The terrace styled swales also need to be seeded and, in my judgment, spread mycelium. The sooner the better, so a strong root system can help hold everything together. The most fertile area will be in the center of the basin, so the way you plant this style swale is different from the first way I mentioned.

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When I make my swales, I also like to cover the high parts in organic matter like wood chips and even saw dust. Mycelium loves wood and grows rapidly ,holding everything together and keeping the mounds from falling apart. Mycelium also loves moisture and helps boost the biological cycle happening under our feet. In a few months, check the soil for worms. This is the number one way I like to judge the health of my soil. You can always grow better in soil that has worms than in soil that is void of worms. Worms contribute nutrient-rich castings and aerate the soil.

Once you have your swales constructed, they still need maintenance. Year after year the ground will settle so just keep piling on organic matter. We maintain our swales in the fall so they have all winter to settle.

Before you know it all sorts of life will develop. I have frogs where we had none and the amount of birds has been amazing. Most of my pest problems are gone because I have all sorts of creatures that love to eat aphids, caterpillars and other nasty pests. Even the moles have disappeared! A big thumbs up for that!

Nothing says you can’t use both systems or a modification of either. I am just offering you an idea of how I use swales to bring life to my soil and improve my property. Swales have worked well for me and I hope to continue adding more!


      1. Just out of curiosity, has there been a project that’s had to deal with larger predators like lions or tigers? I’ve seen documentaries where they’ve shown bee hives discouraging elephants from farms in Africa.

    1. Wasps and hornets may dig in a swale’s berm, but they may dig anywhere on your property. A swale doesn’t encourage wasp and hornet nests, so definitely not a reason not to build a swale.

      1. If you mean water getting into your swales, we want that to happen. If you mean water leaches out the soil nutrients it actually catches and keeps the minerals.

  1. I don’t really like to water…. we have Swales in and are putting in more as we get time… 18 months ago we started with a bare horse paddock that didn’t have dirt and was mainly rock…. to establish our plants esp bamboo we have had to water…. a few months ago we found our first worm….. areas that we first established we don’t need to water as often now…. we live in a dry climate and receive only about 500mls a year and this usually happens in one month…. we hope in the future that we will not have to water as much but know that it is unrealistic to think that we wouldn’t need to water… esp our veggies and fruiting trees

    1. Thanks for sharing Popi. It sounds like you have already made a positive impact. Grow plenty of shade trees and mulch really heavy. That will really help you out.

  2. Built a swale on my property and amazing things have happened. The soil seems to have rose below the swale and also the soil below the swale, soil I did not till in any way, is now super loose. The extra moisture does so much for the soil microbiology!

    1. Hello Oscar, I would think a wider swale. Have you tried making a large Hugel in your swale mound?

  3. Is there any evidence in the literature to suggest that swales or keyline plowing decrease the frequency or impact of wildfires by increasing soil moisture?

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