Here are answers to some of the most common questions we receive about garden plants. You will find concise information on general gardening techniques as well as plant selection and care. For detailed information on specific plant pests and problems refer to our Common Garden Pests and Problems page.

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Horticulture Questions and Answers

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How can I dispose of old waste oil?

We've all heard about the massive environmental problems caused by tanker oil spills. The fact is, one improperly disposed of gallon of oil can contaminate one million gallons of water. Also, Missouri law now prohibits waste oil from landfills because of the threat of groundwater contamination.

Fortunately, motor oil can be recycled. Businesses which have 220 pounds or more of used motor oil, about 27 gallons, are required to contract with a local waste oil company to have it removed. Used oil can be burned in special furnaces or re-refined into more lubricating oil. In fact, motor oil never really loses its lubricating properties, it just picks up dirt and other contaminants from the engine. Once re-refined, its as good as new.

If you change your own motor oil, there are a variety of places you can take it for recycling. Many of the quick oil change companies, service stations and county or city highway departments will accept used motor oil for recycling. Most only charge a small fee, or they may take up to a quart free as a public service.

If you want to recycle your used oil, be sure to check with a local recycling company for their specifications and requirements. Usually, they will accept oil in quantities of five gallons or less and the oil must not be mixed with other chemicals, such as brake fluid or anti-freeze. They will likely test your used oil for contamination before accepting it. If you happen to have contaminated oil, save it in a closed container, away from extreme heat or flame, for the next available household hazardous waste collection day in your area.

As long as you are recycling your used motor oil, you should complete the recycling loop by buying re-refined motor oil whenever possible. The process has become so sound that most large fleet operators, such as highway departments and trucking companies, use re-refined oil exclusively. Also, many automobile manufacturers approve of re-refined motor oil for new car warranties, provided they meet industry standards.