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Is Creosote the Cause When Grass Won't Grow?

Q. Colin writes: "Dear Mr. Mike: My family purchased a wonderful house in Oklahoma City, mostly because of the amazing backyard. However, the previous owner lined the fence with oozing railroad ties and now we cannot get any grass to grow within six feet of the fence. We removed the logs of death before planting sod and seed. Now the dogs are constantly tracking mud and failed-lawn debris into the house. Could the soil be contaminated? If so, how can we neutralize? My lawn guy is stumped as well."

A. I asked Colin a few pertinent questions about timing and seed selection. Here's his reply:

Q. "We sodded fescue in mid-April, overseeded with more fescue in May, and then seeded Bermuda grass in early June. The area is mostly shaded by the fence and our neighbor's fifty foot tall oak. (The tree's trunk is 20 feet from the fence line but we still get a constant sprinkle of acorns.)

"Grass will sprout but will not mature or withstand a mowing or two in this area. The rest of my lawn is very healthy, and we use an organic weed/feed service whose employees are also stumped by our failure to grow anything along the "muds of Mordor". The dogs use other, grassier areas as their preferred relieving spots, just in case you were thinking of them as a culprit. Thanks for your help!"

A. First thoughts: Fescue is a cool-season grass that should only be seeded in early Fall. But fescue SOD applied in April should have thrived. On the other hand, Bermuda is a warm-season grass that should be planted in the Spring. I say 'planted' as opposed to 'seeded' because Bermuda is typically installed vegetatively by putting little plants in the ground, just like Zoysia grass.

Second thoughts: no grass will thrive in deep shade and/or constantly wet soil. That said....

Your soil is almost certainly contaminated with a Witch's Brew of toxins from the creosote used to preserve those railroad ties. They were probably leaking the nasty stuff into your soil for who knows how many years before you moved in.

Keep dogs and humans away from that area by erecting a temporary fence and watch the dogs for any signs of illness or lethargy. Dogs (and cats) have soft paws that easily absorb contaminants. Blood tests for creosote are somewhat problematic, as {quote} "creosote" is actually a complex mixture of chemicals that, according to a fact sheet from the State of Virginia, contains at LEAST 300 different toxins. It is NOT a single element like lead or cadmium.

Explain the situation to your vet; they may choose to run some tests on your pooches or send you elsewhere for a more sophisticated exam.

Creosote is a "restricted use pesticide", meaning they can still use it to treat railroad ties, telephone poles and even {gulp!} wood used to make some 'log cabin' homes. It is a known cancer causer and is especially dangerous to chimney sweeps who clean the highly flammable material off the insides of wood stove pipes and chimneys. Technically, homeowners should not be able to buy it.

The base material can be processed from the wood of the 'creosote bush' (chaparral), which is not a single plant, but a community of like-minded plants that thrive in the torrid deserts of the Southwestern US. The plants are highly aromatic and highly flammable.

But the majority of creosote in use today comes from coal and its residues, especially 'coal tar', which in very small concentrations was (and in some cases still is) used as a remedy for psoriasis. Increase the percentage and you do NOT want to know what kind of cancer you're inviting.

Technically, homeowners should not be able to buy creosote treated products. But even though many sources report that creosote products are somewhat-to-totally illegal to sell to homeowners, huge piles of "used railroad ties" remain visibly for sale at far too many Big Box stores. Criminality without enforcement is just a grease mark on the wall.

OK: Remediation. It sounds like the area is constantly wet, so improving the drainage via drain tiles might be your first step.

Then, move on to physical removal. Many companies perform this task for lead-contaminated soil; they dig it up and take it to a specialized incinerator. Then you'd be starting with a much lower concentration of creosote.

What then? I'm thinking that installing a concrete slab over the excavated area might be the best solution. Stamped and colored concrete slabs look great. Have it cover a larger-than-necessary area, and put a grill, a table and some chairs out there to enjoy the long outdoor entertaining season in OKC. That big tree will even provide some shade!

Otherwise, the Hail Mary Pass here would be to drain the area and then install plants that take up large amounts of toxic material. Remember that matter and energy cannot be created or destroyed; only changed in form. So these plants cannot be eaten, as they will become "full of it". They must be trashed. (I would NOT burn them.)

This technique, properly called phytoremediation, can be extremely effective. A few examples: Alpine penny grass is the choice for cadmium contamination; and Indian mustard (a very attractive plant) removes lead, selenium, zinc, mercury, and copper from the soil.

And the plants shown to remove the most basic elements of creosote (coal tar and pitch) are sunflowers; that's a very nice fence line plant. Just don't eat the seeds, and do what you can to keep birds, bees and butterflies away as well.


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