If you work on cars, you may have a lot of used motor oil sitting around. Some people suggest you can use old motor oil to fertilize your lawn. Does old motor oil really help your lawn? We answer the question, “Can you use old motor oil to fertilize your lawn?” below.
Can You Use Old Motor Oil to Fertilize Your Lawn?
No, you cannot. Not only is it illegal to pour any motor oil on grass but the motor oil will not fertilize your lawn. Motor oil kills grass. In addition, the oil will sink in and kill the soil microbes and invertebrates, like earthworms, it touches. The oil may even contaminate the groundwater where you apply it, if there is enough of it.
What Is In Old Motor Oil?
Old motor oil contains the base mineral oil or synthetic oil, plus dirt, metal scrapings, water, and chemicals it picked up while protecting the engine. It also can contain toxic chemicals and heavy metals. Some of the additives to oil that help it do its job can also remain in it.
What Does Old Motor Oil Do To Grass?
According to a study done by Drs. Beard and Johns of the Texas A&M University Department of Soil and Crop Services, motor oil on grass suffocates the leaf blades. While it doesn’t burn up the leaves like gasoline does, it coats them so that they cannot absorb oxygen or rain into the pores on the leaves. The grass dies slowly but it does die.
Does Old Motor Oil Kill The Soil Microbes?
Yes, used motor oil on grass will suffocate the microbes in the soil. However, after about eight weeks, the soil microbes from areas around the contaminated soil will spread to the areas without them. Earthworms and other soil dwellers will be killed by the oil, too. These take longer to come back to the soil where the oil was.
What Do I Do To Treat Old Motor Oil On My Grass?
If you get oil on your grass, sprinkle laundry detergent on the area. Then rinse the area with lots of water. If you do this quickly, the grass will not suffer as much damage as if you do not treat it immediately. The detergent helps the water wash the oil off of the grass and soil. Be careful that the rinse water does not run off into sewers or drains, as the oil and detergent will contaminate the water in them. This water goes directly into creeks and lakes and will contaminate them, too. Your turfgrass will spread in four weeks to cover 85% of any dead patches treated with detergent. In eight weeks, the grass will cover 91%-95% of the area where the oil was treated with detergent.
What Do I Use To Fertilize My Grass Instead Of Old Motor Oil?
The best way to tell what you need to fertilize your lawn is to first do a soil test. Your local Extension agent has the sample bags and instructions. You should tell them the sample comes from turfgrass. When you get the results, it will tell you what nutrients your lawn needs and how much fertilizer to use to fix that. In the absence of a soil test, use a balanced 10-10-10 fertilizer made for turfgrass and follow the instructions on the label. If you put too much fertilizer down, or the wrong kind of fertilizer, you can burn the grass blades and kill the grass.
What Do I Do With Old Motor Oil?
As mentioned above, it is illegal to dump any motor oil, used or fresh, on your lawn. Instead, you should take it to an automobile mechanic, quick oil change store, or a designated recycling station and leave it there. Some automobile stores and quick oil change stores may charge a small oil disposal fee. However, if you get caught dumping oil on your lawn, you will be fined quite a bit. Depending on the amount of oil on your lawn, you will have to pay clean-up costs as well. The small recycling fee is very little in comparison.
To Conclude
In summary, the answer to the question, “Can I dump motor oil in my yard?” is a resounding “No!” Not only will it kill the grass, but motor oil also kills the soil-dwelling microbes and invertebrates it touches and can travel down and contaminate the groundwater. It is illegal to pour motor oil on grass. You need to take it to an automobile mechanic or some other place that can safely recycle it.
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