Should I Put Rocks in the Bottom of My Raised Bed? (2024)

FAQs

Should I Put Rocks in the Bottom of My Raised Bed? ›

Rocks are not essential for achieving proper drainage and can even hinder it. Limited soil depth. Placing rocks at the bottom of a garden bed reduces the available soil depth for plant roots to grow. This restriction can be problematic, particularly for plants with deep root systems.

Best Soil for Raised Garden Beds

We recommend buying high-quality, nutrient-rich soil in bulk. Or, you can make a soil mix with equal parts topsoil, organic materials (leaves, composted manure, ground bark), and coarse sand.

You can line your raised bed to make it more durable and to prevent toxics from leaching into the soil. For lining, use landscape fabric found at garden supply stores or cloth fabric from clothing. Avoid non-porous plastic, as it can retain too much water and discourage beneficial insects and worms.

A general potting mixture of three parts organic matter (such as garden compost, leafmould or well-rotted manure), two parts sharp sand and seven parts topsoil is sufficient for most raised beds. For alpines, bulbs and herbs, that like good drainage, double the proportion of sand.

A: You should avoid putting rocks in the bottom of your garden bed. A common myth is that this will improve drainage. Instead, this can actually increase water saturation levels as well as allow gravel to mix in with your soil, which can prove very difficult to remove later on.

If you're going to pay for a product to fill your raised beds, again, it should just be really good soil and compost. I only recommend a thin layer of gravel at the bottom of your raised bed and under the edges to help you level the area. Save the rest of your gravel for your garden pathways.

Should a raised bed have a bottom? Despite lining the bottom of a raised bed, the raised bed itself should not have an enclosed bottom. Raised garden beds should be left open to the ground to allow plant roots to grow further into the ground for nutrients if needed.

Covering clippings containing these chemicals can be a problem, especially if you are trying to start planting or using mulch where there are very young plants. Grass cuttings are also a good choice for adding to the raised garden bed as topdressing.

It acts as a physical barrier to block out pernicious weeds. Usually, 2 – 3 layers of cardboard will suffice, though you may want layers in more weed-prone areas. The damp environment created by the cardboard is conducive to earthworms and other beneficial soil microorganisms.

How do you fill a raised garden bed cheaply? ›

To use this method, lay down cardboard or newspaper for weed suppression, and then start stacking branches and logs in the base of your raised bed. As these materials break down, they'll act as compost for plant roots and help raised beds retain water.

Landscape fabric is beneficial for raised garden beds, here are just a few of the many reasons why you should use landscape fabric for raised bed gardening: Prevents soil erosion in a raised bed: As a liner, landscape fabric lets water drain away from the soil while leaving the soil intact.

Start with a layer of landscape fabric to prevent soil from washing out. Above this, a layer of gravel or small stones can aid in drainage. Then, fill the bed with a mix of topsoil, compost, and other organic matter. This layered approach ensures good drainage while providing a nutrient-rich environment for plants.

For a 4x8-foot raised bed with a 6” height, using Mel's Mix: about 5 cubic feet each of compost, peat moss, and vermiculite is needed. It usually takes about two to three bags of purchased fertile mix (1.5 cubic feet each) to cover the bed surface to a depth of 2 inches.

One of the best things to put at the bottom of a planter for drainage is broken pieces of pot. You can use any unwanted plant pots or chipped crockery for this – simply smash them up into small to medium-sized pieces. Adding a layer of broken pieces of pot like this will prevent compost loss out of the drainage holes.

Raised beds that are small and shallow (under 12 inches deep) are typically only filled with soil. Adding other organic materials to shallow beds usually isn't a good idea. Sticks, twigs, and other materials further reduce the limited soil space and can interfere with plant root growth and water drainage.

The answer is yes. You can line the bottom of your raised garden bed with cardboard and newspaper to block out weeds or act as a barrier against rhizomatous, weedy or invasive plants. While some may opt for landscape fabric, cardboard is a more cost-effective option.