Choose some useful garden trays from this collection. You can place these trays on top of your greenhouse staging and place plants in the trays for easier watering. You can fill with capillary matting or Hortag or just leave empty and they can help prevent plants drying out or enable watering from the bottom. Some gardeners use them for short term holiday watering as you can fill the tray with water before you go and let the plants use up the water over a few days. Some of these tray are ideal for a grow bag for the same reason.