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Here’s an interesting question to consider: What do property drainage issues and apiary management have in common?

Rain gardens, of course! Rain gardens are natural solutions to property flooding and runoff problems. Through some nifty landscaping, rain gardens can filter polluted storm runoff while reversing the damage caused by soil erosion. 

Rain gardens, though, also make excellent local sites for natural bee forage. A rain garden can become a self-sustaining ecosystem that’s perfect for natural flora and fauna by planting native plants, all the while keeping your property properly drained. And, with several states offering agricultural exemptions for honey bee colonies, a rain garden can be an ideal way to increase the property’s value for both humans and bees!

What is a Rain Garden (and How Does it Work With Bees?)

A rain garden is a purpose-built feature designed to reduce flooding and standing water, especially that caused by runoff from the street and other urban surfaces. Stormwater runoff is often high in pollutants and toxins, as well as sewage and other undesirable components. In fact, stormwater is the top culprit in the ongoing destruction of urban streams. 

Rain gardens reduce the pollution and flooding caused by stormwater (and other runoff issues). They do so by creating a natural and living barrier. Through a prudent selection of absorbent and native flowers, shrubs, and trees, a rain garden can help keep toxic and damaging chemicals and sediment out of natural water supplies, including drinking water!

While protecting the environment is always a worthy goal, how does this help beekeepers? The answer is simple. Aside from ensuring your local forage sites are kept clean from pollutants, rain gardens can become a local forage site for your bees. 

The goal of a rain garden is to create a natural ecosystem that mimics the local water cycle. The best way to do that is to use local plants. Plants native to the area are:

  • Better suited to the environment and climate.
  • Adapted to the surrounding soil conditions.
  • Ready to grow without fertilizers (and self-sustaining).
  • Resistant to certain environmental damage through natural pest and drought protections.

And, when using native plants used for honey bee foraging, you can create additional food sources for your hives. This can be especially helpful in areas prone to forage competition. 

How to Build a Rain Garden

Building a rain garden is a straightforward process that nevertheless requires some planning. Determining the best place to start building is a crucial step in the process. However, once it’s time to start building, you’ll just need a few common tools.

Select the Best Area

Location is critical in building a rain garden. They function best at the bottom of slopes, or in ground depressions where rainwater usually pools. They can also be positioned to capture roof runoff. If doing so, keep the garden within 30 feet of the downspout, but at least 10 feet away from the house (to avoid saturation issues around the foundation). 

The size and position of your rain garden will depend on several variables. These include:

  • The area of impervious surfaces on the property (including driveways, roofs, and patios)
  • The soil composition
  • The grade of the yard
  • Any buried utility lines

As beekeepers, you will want to consider hive proximity as well. Be sure to match your bee’s foraging areas, if possible. Your rain gardens will also need to receive at least partial sunlight to mimic the natural water cycle.

Study Your Soil

Different soils will have different drainage properties. These properties will influence how large your rain garden should be and if you need any additional soil amendments to help facilitate drainage.

Commonly, soils have four textures: 

  • Sandy: High permeability
  • Loamy: Moderate permeability
  • Clay: Low permeability
  • Silt: Low permeability

Often, your soil will be a mixture of several of these soil types. Fortunately, many ratios work great for rain gardens. Even a property that is high in silt or clay can have beneficial rain gardens with a bit of prudent planning. 

To quickly determine your soil type, grab a handful of earth and add some water. If you can pack it into a ball, it’s probably clay. Sand will crumble immediately. And loamy soils, a mixture of clay and sand, will clump smoothly, but then crumble. 

This quick and easy test is a great way to determine the size of your garden. Clay gardens will require a larger surface area than sandy gardens. Gardens are typically anywhere from 100 to 300 square feet, but they are beneficial in any size. 

Dig, Plant, and Maintain

Before you dig, you can do a little math to determine an optimum size based on your property’s impervious surfaces. Take the area of these surfaces (such as a roof or driveway) and multiply that by the percentage of water you’d like to drain. For example, a house with a roof of 1,500 square feet, and looking for 5% drainage, will need a garden of 75 square feet (1500 x 0.05 = 75).

Once you’ve determined the best location, start digging. You will want to keep the garden level. So, some garden areas will be deeper than others, while keeping the deepest areas in the center. Aim for an average depth of four to eight inches for optimum drainage. 

At this point, you will want to address any soil additions. Clay and loamy soil will benefit from additional sand to help drainage. As you dig, mix in these additions. Use excess soil to create a berm that is six to eight inches tall on the downward side. This will help contain runoff water and higher levels of water. Compress it and cover it in stones or grass to prevent erosion. Finally, prep the garden for planting by layering on topsoil amended with sand. 

When choosing plants, focus on native varieties. Not only will your bees love them, but so will other native pollinators. The plants you choose will depend on your hardiness zone. Some common plants that are great for both rain gardens and bees include:

  • Colorful native flowers (especially blue, purple, and violet)
  • Compositae plants (flowers with centers containing many small florets)
  • Perennials and plants with a variety of seasonal blooms

Don’t forget hardy and drought-resistant plants to create a strong root structure. These include switchgrass and most trees and shrubs that have deep roots. After you plant, place some mulch over the soil, and line the edges with rocks to facilitate drainage. You will need to supply regular water for the first couple of years. But once the garden takes hold, it will become a self-sustaining ecosystem, and an ideal forage source for your honey bees!

In sum, rain gardens are a great and no-nonsense answer to many problems, specifically, harmful rainwater and the diminishing presence of native pollinators. Rain gardens are beautiful, functional, and a wise choice for beekeepers looking to add value to their hives. 

Study Your Soil

Different soils will have different drainage properties. These properties will influence how large your rain garden should be and if you need any additional soil amendments to help facilitate drainage.

Commonly, soils have four textures: 

  • Sandy: High permeability
  • Loamy: Moderate permeability
  • Clay: Low permeability
  • Silt: Low permeability

Often, your soil will be a mixture of several of these soil types. Fortunately, many ratios work great for rain gardens. Even a property that is high in silt or clay can have beneficial rain gardens with a bit of prudent planning. 

To quickly determine your soil type, grab a handful of earth and add some water. If you can pack it into a ball, it’s probably clay. Sand will crumble immediately. And loamy soils, a mixture of clay and sand, will clump smoothly, but then crumble. 

This quick and easy test is a great way to determine the size of your garden. Clay gardens will require a larger surface area than sandy gardens. Gardens are typically anywhere from 100 to 300 square feet, but they are beneficial in any size. 

Dig, Plant, and Maintain

Before you dig, you can do a little math to determine an optimum size based on your property’s impervious surfaces. Take the area of these surfaces (such as a roof or driveway) and multiply that by the percentage of water you’d like to drain. For example, a house with a roof of 1,500 square feet, and looking for 5% drainage, will need a garden of 75 square feet (1500 x 0.05 = 75).

Once you’ve determined the best location, start digging. You will want to keep the garden level. So, some garden areas will be deeper than others, while keeping the deepest areas in the center. Aim for an average depth of four to eight inches for optimum drainage. 

At this point, you will want to address any soil additions. Clay and loamy soil will benefit from additional sand to help drainage. As you dig, mix in these additions. Use excess soil to create a berm that is six to eight inches tall on the downward side. This will help contain runoff water and higher levels of water. Compress it and cover it in stones or grass to prevent erosion. Finally, prep the garden for planting by layering on topsoil amended with sand. 

When choosing plants, focus on native varieties. Not only will your bees love them, but so will other native pollinators. The plants you choose will depend on your hardiness zone. Some common plants that are great for both rain gardens and bees include:

  • Colorful native flowers (especially blue, purple, and violet)
  • Compositae plants (flowers with centers containing many small florets)
  • Perennials and plants with a variety of seasonal blooms

Don’t forget hardy and drought-resistant plants to create a strong root structure. These include switchgrass and most trees and shrubs that have deep roots. After you plant, place some mulch over the soil, and line the edges with rocks to facilitate drainage. You will need to supply regular water for the first couple of years. But once the garden takes hold, it will become a self-sustaining ecosystem, and an ideal forage source for your honey bees!

In sum, rain gardens are a great and no-nonsense answer to many problems, specifically, harmful rainwater and the diminishing presence of native pollinators. Rain gardens are beautiful, functional, and a wise choice for beekeepers looking to add value to their hives. 

Content provided by Rachel Perez.