How to Collect Rainwater: Gardening Guide & Ideas

Rainwater is among the most healthy and beneficial water that you can give your garden plants. The water is clean and natural, lacking harsh chemical-tracers. It also contains trace amounts of helpful nutrients.

Using rainwater in the garden should be a no-brainer. That said, finding the best solution for collecting rainwater for your garden may take some planning.

Best Methods for Collecting Rainwater for Gardens

Over the years innovative gardeners have developed many creative ways to collect rainwater for their gardens. Some gardeners even take things a step further by building systems for distributed rainwater directly to their gardens as well.

Here are a few of our favorite methods for collecting rainwater to use in the garden:

1. Rain barrel

Large 55-gallon barrels, also known as rain barrels, are perhaps the most common contraption used by gardeners to capture rainwater. Rain barrels are available in various sizes and materials. The majority of rain barrels are plastic, though they exist in wood and metal as well.

You can purchase a rain barrel at local home improvement stores such as Lowe’s and Home Depot. They are also available at most hardware stores. Furthermore, you can build one from scratch if you happen to have the materials available around the house.

Once you’ve secured a rain barrel or two, positioning them is the most important step to catching rain. The best places to sit them are directly under downspouts, gutters, and areas where water runs off of your roof.

To utilize the rainwater you capture with rain barrels, simply dip a container in and fill your watering can. If the barrel has a spout/valve, you can even hook your garden hose to it and allow gravity to push the water out and into the garden.

2. Rainwater catchment system

No machine-readable author provided. Pengo assumed (based on copyright claims)., CC BY-SA 3.0, via Wikimedia Commons

For those who have the resources to invest in a more expensive rainwater collection system, a professionally installed rainwater catchment system is a great choice. That said, if you’re the handy-man type, you may even be able to design and install a rainwater catchment system yourself.

These systems are much larger than the 55-gallon barrels used for collecting rainwater by most gardeners. In fact, rainwater catchment systems are typically reserved for off-grid homes and those running large-scale gardening operations.

The average rainwater catchment system consists of massive underground tanks (500 to 2000-plus gallons each) connected to rain gutters. In most cases, the water is then channeled through the house to bathrooms, sinks, the garden, and elsewhere.

The most significant disadvantage of the rainwater collection system is the cost. Additionally, depending on the size and layout of the system a pressure tank or pump may be necessary for moving the water where you want/need it. That said, an additional upside is that you may also add a water filter that cleans the rainwater well enough for drinking.

3. Rainwater tarp

A simple way to collect rainwater in large volumes is the good old rainwater tarp method.

This method requires a bit of work, and a few materials, but is far less expensive than the previously mentioned rainwater catching systems used in off-grid homes and gardens.

To build a rainwater tarp you’ll need a sturdy tarp, a container (such as a barrel), and some PVC pipe. You’ll also need to elevate one end of the water trap and allow the rest of the tarp to slope slightly downhill.

Without raising your rainwater tarp on one end there will be no natural water-flow. Also, at the edges of the tarp, you will need to create small walls or mounds from stones, bricks, or earth. These walls act like small dams and keep the water trapped until you’re ready to use it.

Speaking of using the water collected in your rainwater tarp trap, you’ll want to place the PVC pipe at the lowest end of the trap and connect it to your container. When it rains, the water will run down the tarp, into the pipe, and fill up your container.

4. Cistern

Cisterns are one of the oldest rainwater catching methods known to man. For hundreds of years, if not thousands, people have relied on cisterns for collecting and storing rainwater for daily usages.

Today, we may not need cisterns for our regular water usage, but they are still one of the most reliable methods for capturing and using rainwater for our gardening needs. It is estimated that a 500 square foot cistern can hold between 250 and 300 gallons of rainwater.

Cisterns are simple to build, are generally at least partially covered, and can be underground, above ground, or somewhere in between. The water tanks themselves consist of mainly plastic or metal today. In the past cisterns were mainly stone, wood, or earthen materials such as clay (and if you really wanted to, you could build yours out of these natural materials as well).

Final Thoughts About Collecting Rainwater For Gardening

Aside from the above-listed methods, there are countless creative ways to collect and use rainwater for gardening.

Green roofs and small plastic-lined ponds, for example, alone or in combination with any number of the methods from our list, are a couple of additional ways to successfully collect and put rainwater to use in your garden.

Do you collect and use rainwater in your garden? If so, we’d love to hear all about your personal collection and distribution system in the comments section below!

Good luck with collecting rainwater and using it in your gardens!

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