What to Put Under a Raised Garden Bed with Legs

What materials are best for lining the base of a container garden to prevent soil loss?

To minimize soil loss while maintaining airflow, choose materials that balance fine mesh density with structural longevity.

• Burlap sheets offer a natural, biodegradable option that holds soil well for a single season before needing replacement.
• Window screening provides an ultra-fine barrier that is excellent for preventing the loss of potting mixes containing fine peat or perlite.
• Coffee filters work surprisingly well for smaller containers, effectively stopping fine particles from washing out through larger drainage holes.
• Landscape fabric remains the standard for durability, as its non-woven fibers trap soil particles while allowing water to pass through freely.

How can you ensure proper drainage for an elevated planter to prevent root rot?

Elevated planters require a clear path for water to exit, so avoid lining the bottom with non-porous materials like solid plastic or heavy rubber mats. Use a raised frame that sits slightly off the ground to prevent standing water from wicking back into the soil. Many people assume that adding a layer of rocks at the bottom improves drainage, but this actually creates a perched water table that keeps the soil above it constantly saturated, which often leads to root rot rather than preventing it.

Should you use landscape fabric or hardware cloth at the bottom of a raised bed?

Yes, you should use both materials to create a functional base. The 1/4-inch hardware cloth provides the necessary structural support to hold the weight of wet soil, while the landscape fabric acts as a filter to keep the potting medium from washing out through the mesh openings.

What are the benefits of using a geotextile layer in a legged garden planter?

A geotextile layer acts as a sophisticated filter that keeps your soil nutrients inside the planter while allowing excess moisture to escape.

• Non-woven fabrics prevent the migration of fine silt and sand, which keeps your drainage holes from clogging over time.
• Permeability ratings determine how quickly water exits, so select a fabric rated for at least 50 gallons per minute per square foot.
• Root inhibition occurs when using high-quality textiles, as they discourage aggressive roots from growing through and potentially clogging the drainage system.
• Moisture retention is improved because the fabric slows down the rate of evaporation from the very bottom of the soil column.

How do you prevent pests or rodents from accessing the soil through the bottom of a raised bed?

Securing the base with heavy-duty metal mesh is the only reliable way to stop burrowing rodents from tunneling into your planter.

1. Cut your 1/4-inch galvanized hardware cloth two inches wider than the internal dimensions of the planter frame.
2. Fold these edges upward to create a lip that prevents gaps between the mesh and the side walls.
3. Use 1-inch galvanized staples to secure the mesh to the frame every 3 inches along the perimeter.
4. Inspect the corners where the mesh meets the wood to ensure there are no gaps larger than a pencil.
5. Apply a bead of exterior-grade silicone caulk over the stapled edges to further seal potential entry points.

What is the recommended thickness for a drainage layer in an elevated gardening container?

No, you should not use a dedicated drainage layer of gravel or stones in a raised bed. Adding 2 to 3 inches of rock adds unnecessary weight that can stress the legs and actually hinders drainage by elevating the water table within the root zone.

Can you use organic materials like cardboard or newspaper as a base layer for a raised planter?

You can use organic materials like cardboard or newspaper as a temporary base, but they are generally ill-suited for elevated planters with legs. These materials break down quickly when exposed to the constant moisture of a garden bed, eventually turning into a soggy sludge that blocks drainage holes. For example, a thick layer of corrugated cardboard will collapse within a few months, potentially causing the soil to shift and fall through the bottom mesh.

The main exception is using these materials as a weed barrier in a bed that sits directly on the ground. When the planter has legs, however, you need a permanent, rot-resistant solution like hardware cloth. Relying on organic matter in an elevated structure invites structural failure and drainage issues as the material decomposes and compacts over the growing season.

How does the choice of base material affect the overall weight and structural integrity of a planter with legs?

The base material must be lightweight to prevent the legs from buckling under the combined weight of saturated soil and the liner itself.

Use these figures to estimate the total load on your planter legs, keeping the total weight well below the manufacturer's maximum capacity.