Copper sulfate is found in many household products. Its primary use is as a component of fertilizers, but it is also used as a pesticide and rarely as a cleaner. Copper sulfate is toxic if taken in large enough quantity and poisoning most often occurs after oral ingestion. The compound can cause hemorrhaging in the digestive system, heart rhythm problems, bleeding, convulsions, paralysis and death in insects and other animals including humans.
Copper sulfate is used as a chimney cleaner, especially for metal chimneys of wood stoves. When wood burns, certain chemicals such as resin may not be completely vaporized unless the fire is very hot -- over 250 degrees. Fireplaces generally burn wood above that temperature, but wood stoves often burn at lower temperatures. When that, happens a substance called creosote builds up. If copper sulfate is applied the creosote burns off.
Copper sulfate is also used to clear drains of tree roots. When a root is clogging a septic system, copper sulfate is flushed down the toilet to kill the roots. In the same way, for areas of high humidity where roof algae or lichens are a problem, copper sulfate may be sprayed on the roof to prevent buildup. Likewise, copper sulfate can be used as a spray to prevent fungus from growing on tomatoes.
Commercial fertilizers have copper sulfate in their ingredients, from all-purpose fertilizers to specialty fertilizers for orchids, azaleas, rhododendrons and camellias, plus those suggested for growing vegetables. Copper sulfate is added as a copper source. Mild copper deficiency causes leaves to dry out at the tips and a more severe deficiency results in twisted leaves and leaf death. Leaves produce the sugar of the plants, so vegetables may lose flavor due to copper deficiency.
Snails and slugs are a serious pest for gardeners. A wet mixture of copper sulfate and lime painted on tree trunks and garden walls is an effective barrier to snails and slugs. This mixture is often used by organic gardeners. Copper sulfate is poisonous to all insects and animals, so follow all precautions on the manufacturer's label.