Increase your plant quantity with effective propagation using the 10" x 20" Black Plastic Propagation Trays with holes. Built of durable plastic, these trays have been designed for reuse and longevity. Propagation trays are also designed with the plants in mind, with continuous channels and ridges that prevent water from pooling and harming cutting or seedling growth. Holes also ensure proper drainage, better for certain plant types. Using Propagation Trays, you can quickly double the number of plants in your horticultural system or hobby garden. 10" x 20" With Holes.