Next to my house there are some large railroad tie steps filled with crushed rocks. They appear to be the old kind that were filled with all kinds of nasty chemicals. I assume they are ties, they are about five feet long and about 6X6". I stupidly built my deck using them as footings instead of taking my time and removing them first.
I now want to grow a kitchen garden right where one of the ties is. It would be edged right up next to the railroad tie for about two feet. I am planning to plant a grape vine right next to it as well as other edibles.
I have old railroad ties around as retainers for dirt. I have strawberries growing above one set that is 3 ties high, and onions growing below a 1-high step. I don't really worry about it.
When they were originally creosoted, sure they contained lots of nasty chemicals that could kill lots of plants and wind up where you didn't want them. But then they spent decades sitting under railroad tracks, and the more leachable compounds were leached out with every rain. Then they were recycled when the railroad was taken up, and stacked up some place where even more compounds leached out with each rain. Plus fungal spores began to grow in them as they lost their 'preservative' compounds. About half of my ties are so rotted that they don't really work as a retaining wall. Maybe I should completely give up on them being useful for landscaping and throw them in a hugelbed to complete their breakdown.
If there are soft spots in them, places where rot is obviously occurring, then the fungi have gotten the upper hand and the preservatives are no longer there to contaminate your soil. If weed seeds can sprout and germinate in the cracks in them, then they have lost a lot of their toxins. Since all of mine are in that state, I don't worry about them contaminating any of my soils.
Of course, this is different from the green treated lumber that is often used for decking and other outdoor applications. It isn't creosoted, but treated with a copper-arsenic compound. That type of treated lumber IS a problem and needs to go to a landfill where it will be removed from the biosphere. The copper and arsenic will hang around and create problems if you want to grow vegetables in that soil. Creosoted railroad ties are a whole different matter, and will decompose naturally, although it will take decades, not months or years.
Location: Zone 4A
posted 7 years ago
Thanks, John. The 4X4s are up on patio blocks so their pressure treating shouldn't be a problem.
I have an area where a large building/barn burned down, the soil is decent as far as fertility but full of coal, glass, concrete, rusty metal things, and presumably various mystery chemicals, liquids, powdery things. I just use the area for growing my own seeds; kale, turnips, dent corn, and some beans this year for example.
One method would be to segregate the ties using the most inert thing you can think of... I have used aluminum flashing to shield CCA treated raised beds from the soil, although aluminum has it's own issues and set of detractors.
My wife has a bit of mint growing on an old RR tie retaining wall, it looks very healthy, if appearance can be considered. I hope to be able to replace the RR tie wall with stone at some point, but oh me, it all takes time, doesn't it?
Question if I add lots of leaves to contaminated soil will they lock up of dilute it enough to grow in?
posted 7 years ago
Jeff R Hodgins wrote:Question if I add lots of leaves to contaminated soil will they lock up of dilute it enough to grow in?
Yes, but with one qualification. Heavy metal contamination is harder to "lock up" than commonly used pesticides/herbicides/fungicides/plastics. If your contamination includes heavy metals, if the soil has treated lumber or coal ash in it, then leaves are not enough and you need to add a good bit of biochar to bind them up. Other than that, lots of leaves and the fungi that decompose them will decontaminate your soil.
This thread is old but I'll post anyway. Creosote treated timbers contain a class of chemicals known as semi volatile organic compounds, specifically, polycyclic aromatic hydrocarbons (PAHs). They are groups of multiple benzene rings that are known to be carcinogenic. PAHs generally have low solubility and therefore may not leach away as readily as described by a previous poster. However, a few ties in your backyard probably isn't a big deal...unlike the contaminated industrial sites that I clean up in my profession. If you are truly worried, find a local environmental laboratory to analyze a soil sample for PAHs using EPA method 8270, and have the lab compare the results to your state's cleanup standards. Anything else is just a guess.
After meeting a person who sold chemicals for a living who told me not to go anywhere near the railroad ties for gardening, I take it seriously now. I would recommend to anyone to get rid of the ties they are using and to do it with good gloves. That said, the Mike Gaughan sounds like just the person to take advise from more so than me.
posted 6 years ago
Are you going to give up barbecue? Those PAHs are the same compounds that make barbecue so tasty: applewood, mesquite, hickory, the compounds coaxed out of those to give meat that real smokehouse flavor -- PAHs. Sure, a well done steak may only have a few milligrams of PAHs on it, and a railroad tie has several kilograms, but they are both derived from the same source, creosote.
I would suggest that PAHs fall into that category of "can't live with 'em, can't live without 'em". As for me, I'm still going to keep eating my strawberries and onions from the railroad tie bed, and I'm still going to go for the nice crusty bits at the BBQ.
Location: Southern Indiana zone 5b
posted 6 years ago
I'm not a big bbq guy, either, actually. I have been accused of being a hypochondriac in jest as well, but this chemical salesman was emphatic about railroad ties and telephone poles being very toxic, so I stay away from those things.
For my next trick, I'll need the help of a tiny ad ...