Every DC garden shares the block with rats and voles. They dig under a bed from the alley side and eat sweet potatoes, carrots and tomato roots from below. The fix is built into the bed before the soil goes in.
Line the base with hardware cloth
Staple half inch galvanized hardware cloth across the full base of the bed. Run it 3 inches up the inside walls and staple every 4 inches. Overlap seams by 4 inches. Chicken wire is too open. Landscape fabric does nothing.
Close the gaps
Rats climb. A bed with a lid or a hoop cover of hardware cloth stops the climbers. For a fenced garden, bury the fence wire 8 inches and bend it outward in an L. Rats dig down at the fence line and give up when they hit wire.
Remove the food and the cover
Harvest ripe fruit daily. Pick up fallen tomatoes. Keep compost in a closed bin with a wire base. Cut back ivy and dense ground cover near the beds. Rats travel along cover and avoid open ground.