A growing unit includes a tub that receives plants and a nutrient solution. The base of the tub includes a plurality of channels that drain toward a peripheral channel that extends around the periphery of the tub base. The peripheral channel drains to an aperture that forms a drain. Nutrient solution for irrigating the plants can be provided into the tub through the aperture and, after an appropriate time, can be drained from the tub through the aperture.
