Planters: Sizing

A flow-through planter comprises a ponding zone, mulch layer, filter media for planting, and a supporting gravel drainage layer

a top dressing over vegetation beds that provides suppresses weeds and helps retain soil moisture in bioretention cells, stormwater planters and dry swales.

The engineered soil component of bioretention cell or dry swale designs, typically with a high rate of infiltration and designed to retain contaminants through filtration and adsorption to particles.