Dry Stack Flagstone Raised Garden Beds

Site Selection and Drainage Considerations

• Site selection or accommodation will influence the success of plants in the bed. Make sure that the chosen site will receive an amount of sun suitable for the types of plants that will be grown. Avoid frost pockets, areas with little air circulation that could see the development of fungi and unprotected areas with strong prevailing winds. If soil drainage is extremely poor and there is worry that vegetation in the bed will suffer, consider installing subsurface drainage before the flagstone is placed. Consider adding a sloped trench filled with coarse gravel and covered with landscaping fabric that transport water out of the bed to a lower elevation to offer some relief.

Stone Preparation

• Flagstone is a type of sedimentary rock commonly used for paving and patio projects. Flagstone has been cut into flat slaps that can be .5 to 2 inches thick and irregularly shaped or cut cleanly. Flagstone can be scored carefully using a double-insulated circular saw with an abrasive blade while a steady stream of water runs across the stone. After the groove has been cut, prop the stone up on a log or board and hit one side with a hammer. The stone should break cleanly along the scored line.

Building the Bed

• Dry stacked stone walls are, by definition, built without mortar. This type of wall is flexible enough to withstand some amount of frost heave and short dry stacked walls are typically built without a footing, or foundation. To prepare the site, dig shallow, level trenches where the bed walls will go and make a gravel bed. The base of a 3-foot wall should be about 2 feet wide with a slightly tapering top. Most dry-stacked walls are built two stones wide with small rubble or gravel filling the space between the stones. Bond stones that span the width of the wall are placed atop the two stones and rubble is placed between these. Continue this alternating, layer by layer, until the desired height is reached. Avoid allowing joints between stones in different layers to align.

Soil Considerations

• Filling the raised bed with a good soil mixture will help ensure good plant growth. The soil should retain some moisture but also allow adequate drainage. A sandy clay loam mixed with organic matter such as peat moss or compost will prove the ideal environment for most plants. When filling the bed, slope the soil so that it is slightly higher in the center of the bed.