How can I improve soil drainage and aeration?
Soil drainage and aeration are key factors to plant growth and a successful garden. After setting up your raised beds, loosen the ground below 8-12 inches using a turning fork or shovel. If the ground is very hard or mostly clay, a drainage layer of loose round gravel is recommended. The drainage layer should be equal to about 10-20 percent of the total depth of the raised bed, e.g. 1-2 inches of gravel for an 11 inch tall bed. If setting up beds on non-absorbent surfaces such as concrete or severely compacted dirt, use slatted planter bottoms to provide excellent drainage for gardens on rooftops, driveways and parking lots.
The soil inside your planters should also be loose and well aerated to promote healthy root growth and a productive harvest. Amendments such as rice hulls, pumice, and perlite can be added to soil mixtures to improve both drainage and moisture retention. Root crops and vegetables with long tap roots help to break up soil and loosen hard ground over seasons with minimal digging. After harvesting the edible parts of the plants, leave some of the root systems in place, instead of pulling them out completely. The roots will decompose over time, leaving behind nutrients and loose empty spaces where water and air can penetrate, improving soil conditions for your next crop of vegetables.