Finally, we’ll discuss What Do I Put On The Bottom Of A Raised Garden Bed On Concrete? Such as self-contained pots and beds. Gardener’s Supply has a great assortment of elevated raised garden bed kits if you don’t want to make your own.

Do you wish you could produce your vegetables, herbs, and flowers, but you only have space for a garden bed on concrete, a balcony, or another hard surface? Perhaps you, like us, have a large yard yet want to maximize growing space by incorporating raised garden beds into your hard cape. Perhaps your terrace is simply the brightest location in the house.
Whatever the case may be, I wholeheartedly encourage your efforts to expand wherever you can! Read on to learn how to build a raised garden bed on concrete or other hard impervious surfaces and recommendations and best practices. In this example
I’ll show you how we prepared a new wood-raised garden bed to go on top of our concrete driveway. We’ll talk about drainage, soil retention, and soil quality.
What Do I Put On The Bottom Of A Raised Garden Bed On Concrete?
When setting up a raised garden bed on concrete, it’s crucial to consider what to put at the bottom. Here are some common materials and their benefits:
- Landscaping Fabric: This is a durable material resistant to decomposition, making it a long-lasting alternative.
- Newspaper: An inexpensive and easy-to-use option that can be layered at the bottom of the bed2.
- Wire and Fabric: Creating a “basket” at the bottom of the bed can help contain the soil and promote drainage.
- Cardboard: A budget-friendly option that serves as a barrier against weeds and grass. It eventually breaks down into the soil.
- Various Materials: You can use a combination of materials such as straw, woody material, leaves, grass clippings, rocks, burlap, wool, and hardware cloth.
- Leaf Mold: A nutrient-dense option that allows for the movement of plant roots and worms.
Remember, the size of the bed can affect the yield and ease of gardening. Also, be aware that concrete can stain and may have drainage issues, so plan accordingly.
How Can I Place Concrete On The Bottom Of A Raised Garden Bed?
Planning And Preparation For Raised Beds
Before you get started, there are a few things you should think about. These fundamental principles apply to all gardens, but they are especially important for those planted on a concrete pad.
Location Is Key
All garden beds require sunlight, albeit the amount of sunlight required varies depending on what you plan to plant in the bed. Begin by observing your yard to determine which places receive full sun and partial sun and are generally shaded. You can now layout the initial positions of your beds based on what you discover.
The bed must be placed on a flat surface at the bottom. This is rather simple if the bed is on concrete, but if your yard has a slope, all runoff from the bed will travel in that direction. Know ahead of time if extra moisture will collect someplace on the hard surface. You are turning a hose slightly onto a trickle in the location you’re considering, and see where the water goes a solid technique to test this.
When building raised beds on top of pavers, there may be gaps between individual pavers when building raised beds. Fill these gaps with sand or another substance to ensure your bed soil doesn’t get caught in between. Finer soil qualities might offer the ideal environment for weed growth between pavers, so filling spaces with something less enticing to roots is a smart idea.
When constructing your raised beds, leave plenty of space between them. You’ll need to transport your garden cart or wheelbarrow between these enormous dirt containers. The best choice is to measure the breadth of anything that will need to be moved between beds and add 6-8 inches to that measurement. If you use your cart, you won’t get stuck between beds if you make a tight bend.
Problems With The Watering System
Unlike in other extended bed methods, installing a water feature through concrete are usually not an option. If you want a custom-built patio slab, you can plan your irrigation system ahead of time and then pave over it. On the other hand, the rest of us must choose a different path.
Running a simple PVC system between both beds is an option, but it should be kept away from main paths to avoid tripping hazards. It’s also possible to connect hoses to concrete beds. If not done appropriately, this can pose a tripping hazard. If at all feasible, situate your watering hoses or pipes in the least-used area of your garden.
Hand-watering is always an option, and it’s just as simple as using a built-in system. The construction of a PVC pipe system to convey water to a drip system is your best bet if you want to run your system on a timer while you’re on vacation.
Think About The Size You’ll Need
Growing plants have plenty of room to expand their roots in an in-ground bed. The same cannot be said for a regular raised bed on your patio. I always suggest going with a taller raised garden bed than you think you’ll need.
Even on a hard surface, anything like the tall 6-in-1 steel garden beds from the Epic Gardening store will work nicely to grow food because there will be enough soil depth, and the roots won’t come into contact with a hard slab at the bottom. You might also construct a tall wood bed.
Putting Together Your Raised Garden Bed
Now that you’ve planned for your raised beds, it’s time to put them together. On the other hand, garden soil can discolor hard surfaces like asphalt or concrete. Thankfully, you can prevent patio staining caused by your huge containers with a few simple techniques.
Place the frame of your raised bed on the patio surface to begin. If the frame is steel, a geotextile or landscape cloth should be placed inside the bed to avoid dirt leakage and discoloration of the paved surface. You can attach hardware fabric within wood frames to act as a mesh “floor,” then insert the geotextile fabric inside of that.
The landscaping fabric should cover at least half of the inside of the bed in either case. Fill in the soil inside the geotextile cloth with care, using your preferred raised bed soil blend. Cover the top of the cloth as well, as the weight of the current soil should prevent extra soil from falling down the sides.
Continue to fill the raised bed with soil until you reach the top of the raised bed or the height you want the soil level to stop. A tall, raised bed may require more dirt to fill. If you need to dig down to the bottom of your bed in the future, take care not to pierce the fabric. If you make a few holes accidentally, your patio may become damaged or discolored.
In most circumstances, a good pressure washer will remove the stain. However, some soil seeping may occur during drainage and settling. You can top off the bed with additional soil, but patching holes is more difficult.
Why Is It Bad To Plant A Raised Bed Garden On Grass?
Before you plant your raised bed garden in your chosen location, consider a few things. Is your lawn mowed and, more importantly, weed-free? Grass and weeds will grow through the inches of dirt in your raised bed if you don’t. You’re going to have a mess of problem with it.
You should mow the grass and weeds and undertake a small technique to eliminate them permanently. Soil Solarization is the name of the method. This method entails covering the region of your choice with a plastic sheet and leaving it there for at least six weeks. The chemical is not used in this technique.
The sun will be trapped by the plastic covering, raising the warmth of the soil. Temperature increases also kill grass, weeds, and bugs. This will eliminate grass, weeds, and pests from your region. Before doing soil solarization, you should till the area, choose a thickness of 1.5mm, and avoid using a damaged sheet, as this will allow sunlight to get through and cause the temperature to drop.
If weeds and grass start to grow after six weeks, your soil solarization system isn’t working. Solarization of soil could be damaging to beneficial bacteria. However, because we are using a raised bed garden and adding our soil, this is not an issue.
Conclusion
Here we conclude all about What Do I Put On The Bottom Of A Raised Garden Bed On Concrete? If you make your wood-raised bed, it should survive for many years. The wood will gradually begin to show its age over time, and you may need to replace a board here and there if rot develops. Keep an eye on the bed to see if it develops any decay.
Even if it occurs, you have some time before you have to replace the wood so that it won’t be a pressing concern. As long as the soil drainage is adequate and the raised beds are weeded and maintained regularly, you should be able to grow plants in them. At least once a year, add a few inches of composting or waste blended with soil, and you should see amazing plant growth!