How to Build Raised Garden Beds on a Slope or Hillside

Gardening is possible whether your landscape is beautifully flat or sloped. All yards are not equal, so if you have only a steep hillside available and you have to work with it without doing any major terraforming, there's no need to worry. You can build raised garden beds on a slope or hillside and start growing your favorite plants in them. Building raised beds on sloped ground eliminates the need to till in-ground beds and significantly reduces erosion. Gardening on slopes can lead to soil erosion because the exposed soil and nutrients run down the hill. The key here is to build a level raised bed according to the slope to prevent erosion and enjoy the benefits of raised beds and terraced gardens.

This guide will share everything you need to know about building raised beds on a sloped surface. Roll up your sleeves, put on your garden gloves, and start the project.

Can you Put Raised Beds on a Slope?

Yes, you can put a raised bed on a slope! Building raised beds on uneven, sloppy ground has many benefits, such as improved drainage, an extended growing season, even water and nutrient distribution, reduced erosion, less weed growth, more control over soil quality, and easier gardening. Depending on the steepness of the grade, you will have to dig and level, but the rewards will be worth the effort.

Building a raised bed on even ground involves simply creating a box and laying it down. However, on a slope, only putting the box on the ground will make the raised bed uneven like the ground. You should lift one end or first level the ground to ensure your raised bed is level. All you need to ensure is that the finished bed is level and doesn't follow the ground's contours.

Choosing the Right Location

Most vegetables require 6-8 hours of direct sunlight, meaning full sun. Therefore, choose a location with lots of sunlight for your raised beds. If your site has only partial sun, it will also work.

How to Prepare the Raised Bed Area

If grass is in the area, mow it short and dig it up. Remove all rocks, roots, and plant debris. Then, loosen the soil a little by digging it further with a shovel. In addition, you can prepare the raised bed area using a no-dig method. Mow the grass close to the ground and then place the layers of cardboard boxes above it. This will prevent grass and weeds from growing in your raised bed and rotting in the soil. Some gardeners use a weed barrier at the bottom of the raised beds.

Related Post: Everything You Need to Know about Raised Bed Gardening

Choosing the Right Wood for Raised Beds

Wooden raised beds on the slope work out well. There is a wide range of wood available to build raised beds. Pine is the cheapest and most easily available lumber, but it'll rot in a few years. Rot-resistant lumber like cedar, locust, and redwood last longer but are expensive. Cedar lumber is the best choice for raised beds because it is durable and rot resistant. It can easily last 10 to 15 years. Additionally, it contains natural oils that resist insects and preserve the wood.

Moreover, you can use thicker boards of untreated wood, like larch. Pressure-treated lumber has chemicals to prevent rotting. Therefore, growing vegetables and fruits may be unsafe, as it can contaminate your food. According to the article published by Oregon State University, the impact of modern pressure-treated wood in edible gardens is minimal. One option for gardeners who feel uncomfortable with treated wood is to line the inside of the bed with polyethylene.

What Should be the Size of a Raised Bed?

Raised beds should be no wider than 4 feet to allow you to access the plants without stepping into the bed and compacting the soil. They should be at least 6 inches deep, but 8-12" deep is best for most plants and vegetables. You can make the bed as long as you want, including 4x4, 4x8, or 4x12. However, creating and managing several shorter beds is easier than one long one.

What Materials are Used to Build Raised Beds

Here are the materials and tools required to build raised beds.

• 2 x 6" lumber and extra for filling the gaps
• Stacking Joints
• Hammer
• Screwdriver
• Measuring Tape
• Saw
• Garden Gloves

How to Build a Raised Garden Bed on a Slope?

Once you have gathered the essential tools and planned everything, follow these steps to easily build a raised bed on a slope without breaking the bank.

Make a Raised Box

Build the basic frame of your raised bed using corner brackets by Frame It All, known as stacking joints. These joints are easy to assemble. Raised Garden Bed kits are also available in several sizes and colors. These kits can be assembled in a few minutes and will not require additional materials.

Level the Box on the Ground

Next, stake the downhill side of your raised bed frame to hold it in position. Keep the box level from every direction and in the right place.

Measure the Gap Under the Bed and Cut

Measure the gap under your staked bed using a tape measurer. Next, measure the length from where the raised bed touches the ground. Measure both the tall and short sides of the gap. Mark additional wood with these measurements and cut the boards. The gaps can have a funky shape depending on the contour of your landscape. Cut the boards so that they fit the gap properly. Don't worry if the line or cut is slightly off. You can put extra soil into the gaps or remove a little to level the sides of the bed.

Insert Boards

Insert the freshly cut boards under the staked raised bed. Then secure the boards' corners with braces using wood screws. In the end, check the level of all sides of the bed and adjust if necessary.

Note: With wooden and metal raised beds, level the ground in advance and make sure your bed is not sloping or angled.

Fill Your Beds and Start Planting

The construction of your raised garden bed on a sloped surface is complete. Now, fill it with a nutrient-rich compost mix and high-quality organic soil. Fill the beds and rake the soil smoothly. The soil will settle over time, especially with watering, providing room for adding more soil or mulch.

This helpful guide, How to Fill and Plant in a Raised Garden Bed, explains how to fill a raised bed.

How to Water the Raised Garden Beds on the Slope

The drip irrigation system stands out as the most effective method for watering raised garden beds on a slope. Drip lines, equipped with pressure-compensating emitters, deliver precise amounts of water, unaffected by pressure changes caused by slopes. This system can save up to 50% of water compared to other methods, providing consistent moisture to the plant's root zone. Drip lines emit less water than sprinklers and hoses, which makes them ideal for plants on sloped surfaces, as they minimize the risk of overwatering, evaporation, and runoff.

DripWorks offers a wide selection of drip irrigation kits. Our kits include all the irrigation components you need to set up a system, from durable drip lines to pressure-compensating emitters. The kits are available in small, medium, and large sizes, depending on your garden bed's size.

Conclusion

Building raised beds on a slope or hillside may seem like a huge task, but this is a simple DIY project. You can easily create these beds with basic building skills and minimal tools. Remember to ensure the bed is level to avoid potential erosion issues. By following these simple steps, you'll be able to create productive raised beds, fill them with quality soil, and start planting, and before you know it, you'll have a stunning, thriving garden.

Visit our gardening blog to learn more about raised bed gardening. DripWorks offers a high-quality and affordable selection of metal raised beds and garden bed kits to irrigate your raised bed plants. For questions, please email us at support@dripworks.com or call us on 800-522-3747.