These environmentally friendly funnels conserve water by taking it directly to the roots without wasting water in run off or evaporation. The method of irrigation also creates healthy plants by encouraging root systems downwards in search of water rather than up to the surface. The depth gauge on the side enables you to guide the water to just the right level and the 43 outlets will distribute the water. The depth can be increased as the plant grows. In most cases one funnel per plant is ideal but for large plants you may need to use more to distribute the water evenly.