Copper Sulfate to Stop Root Growth

Application

• Copper sulfate corrodes metal pipes. Feed it into your sewer line through a ceramic toilet, not through a sink or tub drain where it can easily cause leaks. A 2 lb. container of copper sulphate crystals treats a 300-gallon septic system. Apply the compound in a single, daily 1/2-cup increments over a period of several days, instead in a single, large amount. Flush the toilet several times after each addition of crystals. Repeat flushes push the copper sulphate deeper into the sewer line. Semi-annual treatments, if needed, are safe. Home garden centers and pharmacies carry copper sulphate for sewer line use.

Alternative Application Technique

• Not all the copper sulphate added through the toilet travels to the your septic system's lateral lines. Much of the crystal compound eventually settles in the sludge at the bottom of the tank. If your tank's lateral lines feed into a distribution box, add the crystals there instead. They'll spread through the lines for wider leach field absorption.

What to Expect

• Tree roots encroaching on your septic system absorb copper sulfate, but only in amounts large enough to kill local areas of tissue. The dead areas no longer absorb the compound, so it has no toxic effect on the remaining root tissue or tree. The affected roots usually die anywhere from several days to several weeks after exposure. A normally flushing toilet, and elimination of unpleasant odors from your backed up septic tank, signal the copper sulphate's success.

Considerations

• Using copper sulphate against septic-blocking tree roots has its disadvantages. As a heavy metal, copper resists removal during sewage treatment. This makes copper sulphate a possible environmental pollutant. Copper also kills some of the friendly organisms involved in wastewater treatment, rendering the process less efficient.

Origins and Other Uses

• A blue copper sulphate solution (CuSo4) results from heating a mix of between copper (II) oxide (CuO) and sulphuric acid (H2SO4). Evaporation of this solution produces pentahydrated cupric sulphate (CuSO45H20) crystals, the basis for most commercially available copper sulphate products. Most copper sulphate--more than 75 percent--supplies agricultural fungicide or amendment for copper-deficient soils. Copper sulphate has many other uses including as an animal and plant nutrient, insecticide, algaecide and printing- and mining-processes electrolytes.