The Clever Pots Reservoir Hydroballs are the alternative to using broken terracotta pots or rocks to increase drainage and prevent waterlogged roots. It's often a time-consuming task to find enough crocks to fill up the bottom of a pot, promoting airflow and storing water. These cleverly designed hydro balls do that job for you. The pack contains 16, terracotta-coloured hollow balls which create pockets of space for water to gather, which can be easily accessed by the plant's roots. They create a regular water source for a healthy root system and help drainage and aeration for healthy-looking plants. They fit any 40cm+ garden decorative or terracotta plant pots. We recommend using all 16 hydro balls to fill a 50cm pot with a double-height layer before filling it with soil and planting it up. The hydro bills can also create a reservoir in any shaped pot. Simply place the waterproof liner (provided) in the bottom of the pot before adding the hydro balls, and soil and then planting up to create a reservoir to maintain water levels and help keep plants hydrated for longer. This clever system works by lining the base of the pot, allowing water to gather among the hydro balls, and storing it for the plant to access later. Any excess water tips over the edge of the liner and out through the drainage holes in the base of the pot. Directions to use: take hydro ball halves and push them together until they click, and create a ball and place it in the bottom of the pot with the black plastic waterproof liner. Dimensions: D 6 x W 6 x H 6cm. Material: ABS.