Gardman 40 Cell Standard Seed Tray Inserts - pack of 5 A set of 5 x 40 cell inserts for use in a standard size seed tray or propagator. Ideal for growing plants from seed. 37cm wide, 23cm deep, 5cm high. FREE POSTAGE £7.40 Quantity: at £7.40 each Add To Basket Five black plastic inserts for use in a standard size seed tray or propagator. Each seed tray insert consists of 40 individual cells for growing seeds.