Abstract: A single-piece tray for hydroponic cultivation, composed of a plastic material shaped to define identical cultivation cells inside the tray. Each cultivation cell has: a housing defining a raised plane and configured to house a bulb or seedling to be cultivated, with a hole dimensioned to support the bulb or seedling without letting it fall through, while allowing its roots to protrude below the tray; a buoyant portion, defining a lowered plane intended to sink below a waterline, and delimited by side walls, each buoyant portion defining: a bottomside with a first height, a waterline zone with a second height, a topside with a third height; the sum of the first, second and third heights corresponding to the height of the side walls which connect the raised plane to the lowered plane. The side walls forming a channel.