A permaculture swale is a technique for capturing and storing water in a garden. In this article, learn how to build a swale in the home landscape. Oh, and don’t forget to grab your FREE Quick Start Guide: How to Build a Swale to Capture Roof Water at the end of the article.
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A permaculture swale can be an important feature in the productive garden or earth-friendly yard because it helps to slow, store, and spread water. Personally, I discovered it was the perfect solution for creating a low-maintenance, edible landscape in my front yard.
>> Are you wondering what a swale is? If so, check out my article What is a Permaculture Swale: Irrigate the Easy Way for more details.
This article, to clarify, goes into the technical, nitty-gritty details of building a permaculture swale: How to choose an appropriate site/location, and how to build it.
As water flows across a typical surface or landscape, most of it will run off quickly without having a chance to soak into the soil, even on land that appears flat or very gently sloping.
With a swale or another manmade landform such as a rain garden, however, the water flows into a trench or depression, where it percolates slowly into the soil. Consequently, it produces little to no runoff.
To start, collect information about your yard. Where is the water coming from and where does it go?
Write down the following observations.
In permaculture design, we call these passive observations, which are made by asking specific questions about the site. You can learn all about them in my article how to use the power of observation in permaculture design, as well as get my free, 13-page worksheet: Making Observations.
Active observations, on the other hand, are another type of observation. They’re made by collecting data about the site and plotting it on physical maps of the property, to get a visual representation of all the data points that can affect design decisions. It’s a good idea to walk through my map exercises for permaculture design if you goal is a whole-system water plan.
Constructing my front yard swale, 2011
A swale can help capture water before it’s lost in order to irrigate a planting area.
Most importantly, here are some rules for siting a permaculture swale. It should be:
Note: This may not be an appropriate strategy for areas with a high water table or on extremely steep slopes.
Tired of generic permaculture design advice that you can’t apply to your specific goals? If so, check out my Permaculture Design Program and get the tools and support needed to create and implement your own permaculture design.
Mark the contour line every six feet using a contour level and utility flags. The following video shows how to use a simple, homemade A-frame level to mark the contour lines. (Don’t worry, anyone can build one of these!)
It’s essential to mark the contour lines accurately. Swales built off-contour go by other names, such as keyline trenches or diversion trenches.
Certainly, swales are unique to the landscape they’re used in, so no two swales will be the same shape or size. But here are some estimated values for swales in residential yards.
As a reminder, the free quick start guide, which you can sign up to download at the end of this article, will help you with more specific calculations.
Take the soil dug from the trench and place it on the downhill side.
To test whether your swale trench is level, work the A-frame level along the bottom of the trench, as shown in the video above in Step Three. Fix uneven spots.
Next, observe the swale during a heavy rain event. How did it do? If it overflowed, then make the swale trench deeper, wider, or longer.
I recommend planting perennials that grow permanent, thirsty roots in order to stabilize the system.
Should you plant in the trench or on the berm? This depends on your climate. In desert areas, plantings are typically placed in the swale trench to take full advantage of the rainfall before it evaporates. Meanwhile, in non-desert areas, it’s typical to plant the berm, as there’s typically more rain that may overwhelm plant roots.
Try these permaculture-based planting techniques on your swale:
(To name a few of my favorite ideas.)
Always think about where the water will go if the swale overflows, and then build redundancy in that can handle a 100-year rain event. Are you wondering what that means? In other words, you are the director in your landscape. Therefore, if the swale overflows, you need to tell the water where to go next. Otherwise, it will find its own route.
When I built my front yard swale, for example, I directed the overflow into a rain garden to accommodate any excess water. Likewise, if you have the space, you could direct the water into another swale by using what’s called a spillway—which is simply a trench that directs water somewhere.
In residential spaces, aesthetics are often an important consideration. Swales can actually be visually pleasing, although it’s hard to imagine a beautiful setting with a trench running through the yard!
Try filling the trench with gravel or wood chips and you have a walkable pathway. (I prefer filling it with large rocks, followed by gravel, topped with a few inches of wood chips.) If your swale trench doesn’t need to be walkable, however, then consider seeding it with clover or grass, or adding a layer of mulch to reduce evaporation.
Finally, give the berm a pretty border, and you have a raised planting bed.
I don’t recommend filling the trench unless the swale is in a highly visible place where aesthetics are important. That’s because over time, the material in the trench may become compacted from the walking, and you may need to pull it out and replace them over time. In addition, when the trench is filled with material, you can’t see it working, and may not know if there’s a problem.
By observing your system, you’ll be able to notice if a swale berm starts overflowing regularly, or if a swale trench ceases to drain. That’s your sign that it needs a clean-out, re-leveled, or adjusted in size.
My front yard swale: The trench is on the left, topped with wood chips so it can double as a walking path. The berm is on the right, densely planted with strawberries, and given a rock border for aesthetics.
Here’s a picture of our front yard before we added a swale and gardens:
Our house before we purchased it and began our front yard project (2005).
The swale system and perennial plantings work to slow the water, spread it, store it, and lock in moisture. The front yard now looks like this:
Our front yard (2013), after building a swale and planting the edible landscape
A permaculture swale can help you store water in the ground and reduce runoff. Nature does it best!
For more details and pictures of swale-building, see:
Motivation
You might question whether using swales to store water in the ground actually works as well as I’m suggesting. This 5-minute video, Greening the Desert, demonstrates how swales used in the right context can turn desert into productive gardens.
Are you digging a swale in your yard?
This is excellent, I just started some passive rain catching methods and it is working really well. The plants love the extra rain water.
Just saw this reply when I was going over your post again! Went to comment and saw I already did, LOL. I have mostly used swales/berms so far. I have also been using a lot of hay for mulch. Both are working amazingly for our crazy Arizona rains (torrential river making rains that happen a couple months a year, lighter all day rains for 3 months a year, and completely dry the rest of the time). I’ve done some trenching from the roofline to the nearest large plants too and that seems to work well out here too.
I just found your blog through a pin on pinterest and I just wanted to say Bravo – the posts I’ve read so far are great. My husband and I took Geoff Lawton’s online PDC last year and we are building a permaculture farm in SW Washington.
Although we are quite familiar with swales I found your two part post on them very helpful and I learned a few new things – like filling the swale with gravel, etc… to make them walkable paths – brilliant! I’d like to use that idea when we start our zone 1 design (it covers about a 1/2 acre)
Our first swale is almost 300 ‘ long (farm scale!) and we ended up filling it with downed alders from an ice storm turning it into a bioswale. That swale is out in zone 3 and the berm is planted out to fruit trees.
Anyhow – glad to have stumbled upon you. You are doing a commendable job of spreading the good works of permaculture in a way that is easy to digest and apply.
@ Le Femme Farmer: Thanks for your kind words about my two swale posts. It’s encouraging that the information was helpful, even for experienced permaculturists. I love your bioswale idea. I’m sure it is working wonderfully – I would love to see pictures of your work!
Hi, I’m really interested in using swales on my land, it’s heavy clay and very wet in winter and dries like concrete in summer. It’s south facing about 1 in 10 gradient, very rich soil and I’m sure it has a lot of potential. What spacing do you recommend and have you any advice for UK climate situation. I’m willing to hire a digger initially Tilly
Hi Tilly, It’s hard to give specific design recommendations without seeing your site, but I’ll try to offer some guidelines. First, I’m not sure what you mean by “1 in 10”. I’m not familiar with that way of describing a gradient. A lot of things would affect the spacing of your swales. Are you catching water from your roof, or passively collecting rainwater passing through the landscape? How much space do you have? How flat is the land? If you’re catching a lot of water on a sloping (but not steep) hillside, 18 feet distance between swales is a good measure. If the land is relatively flat, however, and you’re not catching roofwater, swales can be farther apart. There are other factors that affect spacing, such as: Do you have machinery that needs to access the space between swales? If the land is steep, swales may not be a good option for the site. Heavy clay can buckle under the weight of the water and cause land destabilization. Instead, try check-log terraces. Best of luck to you!
Amy,
I believe “1 in 10 gradient” means 1 foot drop for every 10 feet of horizontal. (approx. 6 degrees)
Regards
Thanks for doing the math for me, David! 6 degrees is around a 10% slope…that’s pretty steep. We used check-log terraces rather than swales on a 13% slope. I would use a swale anywhere the hillside flattens out a bit, either at the top (at least 18 feet away from the edge of the slope) or the bottom of the slope, but probably not on the steep part.
This is such great information. It has really made me think about better planning and usage of space to benefit what I am growing. Thanks for sharing at the Homestead Blog Hop! Hope to see you there again this week. 🙂
Mountain Man has “no choice” ;)- but to read this post tonight! This will be featured on Homestead Blog Hop tomorrow. Thanks for sharing! Jen
Yay! I’m so glad it will be useful for you! And sorry to Mountain Man for all of the digging he’s about to embark on 🙂 Thanks for the feature on Homestead Blog Hop.
This is great information! Bookmarking this for lots of future reference.I was wondering the same thing when we filled in the trench of our swale. It seems like it would obstruct the function of the swale, but in our case it didn’t. I think as long as your swale has an overflow–like our rain garden or the more traditional spillway–the swale should work okay. Before filling in the trench, be sure that it can handle a regular rain event without overflowing. If it can’t, it may be advantageous to make the trench wider before filling it in.
Amy! It’s wonderful to see your blog so successful!
Working with you and your husband at Enright seems so long ago. I’m now in Kentucky, on 10.5 acres and digging a swale/catchment pond—we’ll see what it turns out to be. The edible planting idea is perfect and I can’t wait to make it happen.
Hi Christine–time flies! Congrats on your big property — so exciting! Good luck on your swale–let me know how it turns out 🙂
HIAmy
I’m really late on this thread, but I’m wondering if there is a use for the swale in growing water -dependent plants – like water cress for example. (instead of making the “lake” part of the swale into a walkway, use it for riverine plants like ferns etc)
Also, is there a way of incorporating water features with the swale or is it recommended to keep the ttwo separate?
Great questions, Greg. Yes, you can plant water-loving plants in the swale trench if you don’t need it for a walkway. Keep in mind that the trench can become quite dry in the heat of the summer, and only remain moist during the rainy/cooler seasons. It will depend on your climate. For some other ideas, here’s an article I wrote about water-loving edibles that can also withstand those dry periods. You can connect swales to other water features. In my front yard, we directed the overflow from the swale into a rain garden.
Hi, i am just coming across your website. I have just moved onto a new property. mostly clay soils. very waterlogged at the moment. flat. reading this, i see there are some contours, although slight. i will be putting those to use. hopefully i will be able to do the work necessary!
It sounds like swales could be beneficial to your landscape, but they are a lot of work to create. Host a digging party with your friends or hire a Bobcat-type excavator to help you get the job done more easily 🙂
I really enjoyed your design. It is one of best projects I have seen. Where did you get your inspiration to make this design? Thanks for sharing. I’m happy you shared it. What are your ideas for your new project?
Lots of ideas for the new homestead. I’ll be sure to write about them as we develop them more fully 🙂
Can I take a picture of the area that I need to have some type of drainage done and you kind give me some suggestions.
Hi Brenda,
It’s nearly impossible to consult via photo. Your best bet is to find a local consultant who can help, or take a permaculture course that can help you learn to read your landscape. This isn’t easy stuff!
Hi Amy! LOVE your site! Here’s a question I hope you can answer soon (since I’m doing it in the next couple days over spring break). If I dig a trench to capture redirected roof water, fill it with gravel and plant along the edges, do I have to use landscape fabric before I fill it with pea gravel? Will the dirt from the side seep into the gravel so it can’t drain as well? I’d rather not, but I trust whatever answer you can give me. Thanks for being my #1 inspiration – I’m in the process of digging up my front yard and planting with herbs and edibles. Your pictures were the thing that convinced my husband to give me the go-ahead. 😉
I may have missed your project window, but yes, I would recommend the landscape fabric. The worst that will happen if you don’t use it is that your swale trench will need re-dug sooner than if you didn’t use the fabric. Most swale trenches that are filled eventually need to be cleaned out and restructured to reap the original benefits. But don’t let that scare you. Depending on your soil and size of the trench, I would estimate maintenance to be every 10 years or so, perhaps even longer.
Hi Amy! Your articles on swales are wonderful. I am looking to dig one this fall before the rains hit our Portland Oregon area. We are in the west side outside of the city. My daughter has two girls age 2 and 6 months. Out goal in her long narrow back yard is to create a functional safe play area for the girls, plus perhaps some food growing.
The yard is about 16′ wide and 45′ long, sitting downhill from the property next door. In heavy rains the yard has standing water, and is mucky and muddy all rainy season. There is some french drain that may not be functional but it only goes partway the length of the yard. Where the drain ends there is a shallow, narrow trench that was dug in peak rain as an attempt to drain the yard of standing water. For now we are working to get rid of the current grass and mulch the yard. I’ve seen debate on landscape fabric, and am leaning toward putting down something like cardboard or newspaper and just lining the swale/spillway for rainwater with river rocks. Since the land is down slope from the neighboring land on the east, we would berm to the west and to the east plant some rain loving plants. We have 8 to nine months of rainy weather with occasional heavy rains, but mostly misty light rain. Then summers are very dry with months of little to no rain. Obviously we have limited options in the space, We plan to use ecolawn alternative seed that includes clover and fescue for the area west of the berm and rain garden seed mix for east of the swale/spillway. I think what we are really looking to construct in our limited space is less a swale and more a spillway to direct the run-off from the neighboring yard and driveway uphill. Any comments or suggestions are welcome. Thanks for your blog posts.
Mary, It sounds like you could really benefit from a consultation with a local permaculture or landscape designer in your area. I can’t substitute for solid advice from a professional who can visit your property, but it sounds like you’re dealing with some frustrating water challenges. My guess is that you would do better with a drainage solution that channels the water away from your yard, unless you’re looking to do a whole lotta maintenance on a planted rain garden/swale/berm area. I missed the part about why you’re removing grass. I wouldn’t do that unless you’re planting the area with deep-rooted, rain-loving plants. My experience is that mulching a mucky area invites mosquitoes. A swale might be a good solution here, but without seeing the property, I can’t guarantee it. If you do try to construct a swale, you’ll want to place it as uphill as possible.
Howdy from southeast Texas! I am a numbers guy myself and trying to figure out calculations for swales I’m designing currently and those I’ll be designing in the future. We were taught in our PDC to calculate catchment x max rain in 24 hours. Take that number and divide by 24 to get max hourly rainfall. Then we divide by 60 to get minute rain and 60 again to get second rainfall. We need this data to calculate the amount of runoff we will need to allow to outflow during extreme events. What I’m stuck on is the length of the spillway to avoid erosion even during these extreme events. For example, if I have 22″ max rain in 24 hours and my catchment is just a roof like what you’re doing here and directing that into a swale, which is what I’m actually doing, so the catchment is 1200 square feet. That gives me a max rain event of about 1/3 inch per second that I would need to allow for outflow. If I wanted only about 1/2 inch of water spilling over my spillway, it would seem that I would only need a spillway of a little less that an inch. That does not sound right but I’m not sure where I’m going wrong in my math. Or am I correct? I would think something like a 2 foot spillway would be more appropriate but that’s just a guess. Do you have any insight into this? Thanks!
I have seen a few different methods for calculating spillway dimensions. As I mention above, one method is to make the spillway about as wide as the trench. So if the trench is 2 feet wide, that will be the width used for the spillway. Brad Lancaster in Rainwater Harvesting for Drylands, Vol 2 states that a spillway will be twice as wide as your berm height, measured from the bottom of the trench to the top of the berm. So if your berm is 18 inches tall, the spillway would be 36 inches wide. He also says that the spillway will be indented to 1/3 the height of the berm, so if the berm is 12 inches tall, the spillway will be indented 4 inches. There are a lot of variables that determine how much water the spillway will have to accommodate at a given time. The best thing to do is construct a swale using a method (like the one you were taught), and then observe to see how it does in a heavy rain event, which we would do anyway before planting. Our best work happens when we are willing to observe and adjust, since nature can surprise us 🙂
I purchased a home in Ooltewah TN and the home inspector suggested adding a swale along the back left and side of the home to keep water from entering crawl space. Looking for a Chattanooga company competent in swale installation.
A swale that a home inspector suggests is likely different from the permaculture swales that I discuss here (two techniques with same name). The home inspector is likely suggesting something like a diversion trench that diverts water away from the home, while a permaculture swale is constructed on contour to hold water and encourage it to sink in. This would likely not have the desired effect next to your foundation/crawl space. 🙂
Hi. Very useful article, thanks! The street we live on was poorly constructed, meaning all the yards and storm water drains are lower than the council drains they are supposed to empty into. We can’t change that unfortunately. There is a holding ‘tank’ in the ground at the point where our rain water exits our property and that takes care of most of the water in light rain. However, in heavy or sustained rain, that tank will fill beyond the exit drain level, leading to water ponding in our front lawn which takes some time to drain away. We are planning to dig up the front lawn to lay some french drains but unsure of where to locate them and how deep is best. Can you help with some guidance? Thanks for any advice you can offer.
Managing water properly is incredibly important, and the best way to have the water managed properly is to work with a professional. As a landscape designer, I cannot give advice about whether french drains are the best solution for you, where to lay them, or how deep, without seeing the property. Having something done right the first time can be a lot cheaper than doing it wrong and having to redo it.
I have major drainage issues at my new house. Heavy rains always results in a flooded backyard sometimes as deep as 6 inches of water. Unfortunately there is a walk out deck on the back side of my house and adding fill under it would very difficult if not impossible. I’d like to fill in the back yard so that water won’t stand there but that would bring it higher than the grade underneath the deck. My initial idea was to install a French drain from my back yard all the way around side and to front yard of my house where there is a drain that empties into the storm sewer.
The side and front yard is already graded towards that low spot but the back yard is only a few inches in grade above this drain with a high spot in between keeping all the water in the back yard.
I was told by a couple contractors that a French drain would not work. It would freeze in the winter and not have enough pitch with about 250 ft from back yard to this drain and only approximately 5-6″ drop over that distance.
It seems my only option is a swale to avoid freezing and also be able to make best use of the minimal pitch. I’m hoping to raise grade of backyard slightly and have the swale just barely lower than current grade to maintain a minimal slope away from the back of house without adding fill under the deck.
My problem is the swale would separate the steps coming down off the deck and my back yard.
Aside moving the steps and running the swale underneath the deck I don’t know what other option I have but have an unsightly swale to step over every time we go from the deck down to the backyard.
any ideas or input would be helpful.
Also, what machinery would be most effective for installing this swale? Rototiller and shovel or backhoe or?
What about finish grading? I’d really like keep the swale grass or it will stick out even worse separating my yard.
Thanks,
Ryan
This is not an issue that can be diagnosed via internet, unfortunately. If the contractors you spoke with couldn’t offer an alternative to a french drain, then I would suggest seeking out opinions from other contractors. Landscape architects and permaculture designers would be really helpful in this case. It’s possible the deck in its current form is not a good match for a proper water solution. It’s important to be open to what a long-lasting solution would look like.
the only contractor that wasn’t just a flyby night hack does nothing but drainage. He suggested just regrade better slope and be done. I’d like to integrate a gentle swale into this at time of grading for quicker water removal.
This guy also said he doesn’t know any other company within 100+ miles that specialized in drainage. Most places I called were landscapers and some where diggers and excavators. The local excavators that would most likely do a good job on my project are too busy to waste their time on a project the size of mine. The only landscaper that looked at it said they can do whatever I want saying it would most likely cost around $6-7k to regrade and add better drainage. He wouldn’t go into details and sounded like he wanted to just wing it and charge me an arm and a leg for what would most likely turn out to be an inadequate result. There is what looks like a pond 15 feet away from the deck steps now with majority of backyard flooded and unusable. I guess even a small ditch/swale in front of steps would still be better than what I have now. Maybe I can extend the bottom step and add a small storage area with decking and run the swale under that. It would be easier than installing a swale under an existing deck.
still curious on best equipment to accomplish something like this.
We have about a foot of soil above granite ledge bedrock. There are two spots where the properties of a swail might be nice, but is there enough soil for water to sink into? Below these areas, the water pools and I am hoping a swail might help, but it may be that the water holding capacity of the soil (at least in peak wet periods) has simply been reached already?
Swales can be very useful in areas with shallow soil over bedrock. In flatter areas, bedrock prevents water from draining, and therefore encourages standing water. Eventually water drains, of course, through evaporation and by percolating into cracks and crevices in the bedrock. These pools of standing water after a rain aren’t inherently bad for the ecosystem, in fact, they are their own ecosystem, attracting plant and animal life suitable to the conditions. However, this can be a difficult place to grow in. In this case, swales add dimension to flat land and create microclimates of higher dry spaces (linear plantings along swale berms) and lower areas that collect and hold water. On gently sloped land with shallow bedrock, swales catch and slow water higher up in the landscape to help bring life to these spaces. Linear plantings along swale berms on slopes take advantage of water before it collects in the valleys, giving you more options for growing space. Swales can be ideal for managing heavy rain events during peak wet periods. Planting the swale with grasses, legumes, and shrubs will help accelerate establishment of a root mat that holds soil in place to prevent erosion, catches and holds more water, increases soil microbial activity, and takes advantage of the minerals present in the rock. This is the beginning of creating a foundation of healthy, bioactive soils with bioavailable minerals.
Hi Amy! I’ve read your book and I love both it and your website! Your directions are easy to follow and I really appreciated the videos and pictures as I’m very visual. I was wondering if you could advise me on a potential problem with our first swale…? Our newly built house sits on compacted clay so the water in our newly dug swale doesn’t drain at a satisfactory rate.
I’m unsure as to whether I need to intervene now or allow berm plant roots to work on improving the soil. My internet search hasn’t been fruitful so I wonder if you could advise…?
Hi there, I’m so glad you’re finding some useful information from the book and here at TAF. In step 2 above, I’ve referenced an infiltration test that is important to conduct before digging a swale, because, as you mentioned, it’s essential that water be able to soak in. 🙂 But tap-rooted plants are your friends. Consider sowing daikon radish, dandelion, and/or lupine into the trench and berm. They are your ‘decompaction team’, drilling into the clay. Let them die back naturally. As they do, they will create a compost corridor that accepts and infiltrates air and water a bit more each year. But also make sure that your swale has an overflow to manage the excess water that the swale can’t manage yet.
Thank you so much! I got so excited to start I just started digging. 😅 There’s a lot of rehabilitation that needs doing for our soil. Appreciate the advice 😁👍
Amy, love your site. I am a gardener and recently introduced some permaculture techniques into my installation/design projects (thanks to you!!). I am currently building a rainwater catchment system for a client with a very subtle sloped yard toward the sidewalk (much like your layout). I have created a trench from the two front downspouts (rain chain soon to go on) with a berm on the downward facing side of them and they both then merge together and funnel into a raingarden about 6′ in diameter with a berm around all sides except the entrance from the swale. I have two questions, the first being related to Mandy’s question above.. should I have used the existing soil from the trench swale to make the berm? It is basically all clay, but I included the sod so this should break down a bit to add organic matter. I topped it with some compost (tried to work it in a bit). It is SO dense.. worried the water will not be able to absorb into the berm…. should I pull most of the berm clay material off and start over with compost/loam/peat moss blend? I fear I made a huge mistake. Would love to hear your recommendation on this clay matter. 🙂 I also wonder which strawberry has a deep root system? from my experience they all seem to have a very shallow runner.. hmm would love to learn more about this.. :))) Thanks Amy!
Hi there!
I try to use at least some of the native soil in the berm. You’re right in thinking to improve the clay, though. The decomposing sod and working in some compost will help to make the berm more absorbent and plantable. I’m partial to ‘Seascape’ everbearing strawberries, but have recently planted Junebearing ‘Jewel’, and really like them as well. Mature root systems grow deeper than the roots of first-year runners. 🙂
I am studying your site and ideas on how to divert water from a hill away from my neighbor’s house, then to the creek. What does 5’berm, 2′ above the flow line of the swale mean? Someone suggested this. I am a newbie at this. Thank you for any help you can give me!
A diversion swale (which you’re referencing) is different from a permaculture swale (which I’ve written about here — in which we endeavor to keep more water onsite for conservation and gardening purposes). Your best bet is to consult with local landscapers who have experience managing water issues.
ahh! love the info will try in my little box garden we have here to do a swale it will not be easy but imagination is everything.
Hello! I want to get rid of the grass and other random ground cover growing in front of my house (except perhaps the wild strawberries), and I located where I want swales and flagged them. Do I need to dig out both the swale and under the berm, or just the swale area, and the grass under the berm will die as it is covered in dirt? I also tried breaking ground but found some 20+ year old landscaping fabric under the grass… I know I will probably need to get it all out or else roots may not be able to go down to the water. I am not looking forward to that, as the shovel had difficulty penetrating it.
There are a number of different ways to do it. Because I’m partial to doing less work, I like to cover the berm with cardboard, so that the grass doesn’t grow through the new soil that I add from the trench on top of it. But you could also cut and remove the sod, or cut the sod and flip it over to decompose in place. Any of these methods work fine. I’ve seen people not do anything about the grass under the new berm, and it usually becomes a grassy mess that ends up killing or inhibiting baby fruit trees. Especially if you plan to plant fruit trees in the berm, I would address the grass issue b/c they won’t thrive with grass competition.
Dear Amy, my soil is almost pure beach sand and so holds almost no water. Would it be any use my building swales?
Yes! Swales can be excellent ways to catch water and accelerate soil building. Encouraging mycorrhizal fungi is the fastest way to stabilize sandy soils, and do you know what they need to survive? Living plant roots. 🙂 Hugelkultur swale berms aren’t always needed, but in this case, I would start with a woody foundation, then add the soil from the trench, mixing in generous amounts of worm castings and a mycorrhizal inoculant, and finish with a light layer of compost soil. Water it well, or better, wait for a rain to settle it all. Then plant immediately with your perennials – trees, shrubs, herbs, nitrogen fixers, and sow seeds of quick growing ground covers like clover. Keep it watered until everything gets established, and now you’ve got a soil building/soil stabilizing/water regulating machine.
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Hi, I’m Amy!
Join me as I share my permaculture gardening adventures in the suburbs.
