Framed or mounded, raised beds give plant roots the space they need
Some plants absorb excess nitrates or oxalates from the soil and store them in plant tissues. Toxicity problems can occur in animals which feed on these plants.
Gardening in raised beds has been a common practice for centuries. "Raised" means the soil level in the bed is higher than its surrounding, and "bed" implies it is small enough to work from the walkways.