Environment, Gardening, Homesteading, No SF, Off the Grid

How to Build a Rain Garden Step-by-Step & Why It Helps Protect the Environment

Posted on by Philip Piletic
12
Apr

Rainwater harvesting is one of the most important things anyone can do to help preserve our environment. We don’t have an unlimited amount of fresh water at the moment. Plus, rainwater that runs off your roof is better off being used than running down the drain. Roof rainwater is typically filled with heavy metals and chemicals that leach from roofing materials, animal droppings, and many other pollutants. This polluted water will make its way down the drains and into our rivers.

Rain Gardens Are the Perfect Solution

Rain gardens allow homeowners to collect rainwater, put it to good use by growing beautiful plants, ensure that it is conserved in the ground and filtered before it passes into lakes, rivers, and the groundwater. Water can be diverted from driveways and roofs into the rain garden, plus the way the garden is designed will mean most water in a storm will naturally flow into them instead of ending up in places that could hurt our health.

We’re going to look at the steps you need to take to create one, but first, make sure your tool shed is in order. You’ll need tools, so ensure the clutter is gone so you can find them and they’re all stored away neatly. Once you’re done we’ll proceed to focus on the individual steps you need to take.

A quick Step-by-Step Guide to Building a Rain Garden

1 – Choose Your Location

Make sure your rain garden is at least 10 feet away from your home, plus it should be at a low point in the ground to help it attract water naturally. The downspout on your house and garden shed should be able to reach it too. This can easily be achieved with downspout extenders for short distances and non-perforated drain tile for longer distances. Another option is to collect the water in large barrels or troughs straight from the gutters. The disadvantage is that you’ll have to hand-carry water in smaller buckets to the garden. The advantage is that you won’t have a large volume of water rushing into your garden during a storm, damaging plants, washing away soil and defeating the environmental purposes for your rain garden. Controlled watering from a container with a dispersing head produces gentler watering that is targeted and less wasteful.

  • Downspout extenders ($12-$25 each)
  • A 50-foot coil of drain tile ($24-$30 each)
  • 50-gallon rain barrel with lid ($35-$70)

2 – Ensure It’s Large Enough

When you’re collecting water from a roof it’s going to have a big surface area, so you want your rain garden to handle it easily. You’ll have to work out if the area is large enough while taking the type of soil into account.

3 – Designing Your Rain Garden

You’re not just trying to protect the environment at the expense of your beautiful garden. The rain garden needs to be attractive too, which will mean sitting down with a piece of paper and coming up with the perfect design.

  • Graph paper pad ($4-$6)

4 – Choosing Specific Plants

The same kind of thing applies when you’re choosing plants. You want to pick the ones that will make your garden more aesthetically pleasing. One big piece of advice is to use native plants as they’ll be able to handle the environment. The experts at your local gardening center will assist you in selecting native plants that will do well in local soils. Consider digging a hole and selecting samples from the topsoil and underlying soil layers to take with you for the plant expert to inspect.

5 – Start Mapping It Out

Now you will have to create the shape you plan on using based on your previous design work. It needs to be mapped before you do anything else. It’s also worth finding out at this point if there is anything like pipes underground. In the US and Canada, use the Call 811 service, and someone from the local utility company, usually at no charge, will locate and mark pipes and wiring on your property, so you can avoid the danger and damage of hitting them.

  • 22-foot tape steel tape measure or 50-foot fiberglass tape, depending on the size of your project ($4-$24)
  • Wood marking stakes ($4-$8 per bundle)
  • Sisal for outlining garden boundaries before digging ($3-$5)

6 – Now It’s Time to Dig and Fill

Once you’re sure everything is clear you’ll be able to start digging the soil away. You want to make sure you dig between 4-8 inches deep and measure it just in case. Use some of the soil if you want to build a berm around the edge. If your soil is clayey, this depth will likely be sufficient. If you have sandy soil, especially where your climate is dry, consider digging down 12 inches and lining the bottom of the garden bed with rotting timber from nearby woods or locally purchased firewood. This is an eco-friendly permaculture technique like hügelkultur but in bed form. Timbers absorb water, requiring far less watering of the space should little rainfall. The humus and nutrients produced by the rotting wood encourage plant health too. In sandy soil, a layer of clay can be effective for water retention and for filtering pollutants. Soil scientist Gary M. Pierzynski of Kansas State University says, “Many soil clay particles have a negative charge and will attract any constituents in the water that have a positive charge (e.g., some heavy metals, salts, organic chemicals, and pesticides).”  Minimizing the negative impact of these contaminants on the soil and groundwater is a primary reason for building a rain garden, of course.

  • Locally sourced firewood ($50-$70 per cord, sufficient for a 10’x20’ garden bed)

7 – Getting the Soil Ready

You’ll want to add 2-3 inches of compost into the hole you’ve dug, but it will also need to be mixed in with most of the soil until the ground is level again. You need to ensure you mix everything together properly. The greenest source of compost is your own yard and non-meat food waste. Fruit and vegetable rinds, seeds, egg shells, bread, grass cuttings, tree pruning waste and much more can be composted. Here’s a comprehensive list of things you should and should not compost and instructions to guide you.

8 – Planting Your Flowers

Go back to the design you came up with earlier, and lay your plants in the ground. Make sure they are roughly 12 inches apart. Once they’re safely in the ground you can use your hand trowel to put flowers and grasses into the spaces.

9 – Mulching the Rain Garden

When you’re mulching it’s good to use coarse wood chips as they won’t fly away when the weather gets bad. It should be around 2 inches deep once you’re finished, which will help to lock all the moisture in.

Conclusion

Let’s summarize the many advantages of harvesting rainwater that falls on your roof.

  • The polluted water is diverted from storm drains that empty into lakes and streams
  • It can be filtered through soil before entering groundwater
  • Water can be conserved in a permaculture garden so that fresh water isn’t required for keeping the garden green and growing
  • Research shows that, with specific precautions, harvested rainwater can be used to grow edibles

If you’re looking for a project that is good for people and the planet, planting a permaculture-based garden and watering it with harvested rainwater is a very earth-friendly choice.

Editor’s Note

There are some roofs, even some asphalt roofs, where the water can be collected and then be filtered and used as drinking water. It may be worth some research and lab testing. Before you use rainwater collected from a roof in a food garden, and especially for drinking, it is usually a good idea to get it tested.

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Philip Piletic

Writer, traveler and freelancer who enjoys his garden in the spare time. I have a strong interest in ecology and sustainability and I believe that the global changes can happen one small step at a time.