Also, the type of water you use to water yor plants may affect their growth. If you have city water, which is typically treated with chemicals, it is best to allow the water to stand for 24 hours to allow the chlorine to diffuse out. Hard water (high mineral content) is not good to use as the minerals from the water are left behind in the soil and over time, upset the root-soil osmotic balance and may become toxoic to the plants. If you see a white crusty buildup on the surface of the soil or on the insides of the pot this is a good indication of mineral salts buildup. Converesely, softened water removes calcuim salts but adds sodium to the soil and can also create problems. Plants may develop symptoms such as leaf browning on the tips or edges of the leaves due to salt/mineral buildup. One good way to avoid these problems is to place a filter on your faucet.