FIG. 1 is a top front left perspective view of an irrigation tray showing our new design; FIG. 2 is a top plan view of the irrigation tray of FIG. 1; FIG. 3 is a bottom plan view of the irrigation tray of FIG. 1; FIG. 4 is a left side-elevational view of the irrigation tray of FIG. 1, the right side being identical thereto; and, FIG. 5 is a front-elevational view of the irrigation tray of FIG. 1, the rear being identical thereto.