If you google creosote and vegetables you will find that a vast majority of the opinion recommend not using creosote treated wood near vegetables, and of course a few differ and say it causes no harm.

You have already built the bed, so it is not a question of should you use it. You ask how to keep creosote from leaching into the garden soil. IMHO, that will be darn near impossible. Flashing will prevent DIRECT CONTACT, but will not prevent rainwater from LEECHING creosote into the soil.

Maybe someone else has a better answer. My experience with creosote goes back to when I worked at a State Park that used creosote coated ties to prevent erosion at the waterline of the lake along a sidewalk. I remember always seeing an oil slick emanating from the ties in the summer. And I remember it irritating my skin when I had to do maintenance work along those banks. As you may have guessed, I'm not a big fan of creosote treated wood.

Russ

I don't think you'll find too many fans of creosote-treated wood, especially on an organic gardening forum :-)
However, railroad ties DO exist, are plentiful, relatively inexpensive and pretty longlasting as wood products go. So the issue remains of how to deal with them if you've got them.

One method that has been recommended is to line the bed with a heavy mil plastic, like bamboo barrier, making sure there is adequate overlap at the seams and with the plastic extending below the ties several inches, like a curtain. 6-8 inches is ideal. This should minimize any leaching directly into the planting bed and the root zone of the plants but unfortunately won't stop leaching into the surrounding soil.

There is also a lot of variability in the amount of creosote that will leach. Relatively "young" ties that have not weathered for long will generally leach far more than those that have been hanging out and exposed to the elements for a number of years. If the substance is very visible on the lumber surface, then chances are it's still pretty fresh. FWIW, I'd never suggest using ties or creosote-treated lumber anywhere near a lake, stream or other water source.

oosul, If it was a flower bed I'd keep my mouth shut. But a veggie garden???.....I've seen people cut these after they have been in their yards for 40 years and the smoke from the chain saw cut was so nasty that I had to leave...it wasn't the saw...it was the wood....after 40 yrs. Think about it. This is the organic forum so I assume you care. To me this isn't an airy fairy issue: this stuff is nasty and not what I'd want to be eating....just my 2 cents.

I once lived in a house made of railroad ties, linked together like a log cabin. Now here I am, just turned 70 and already my right middle finger has a stiff knuckle, I sometimes forget my phone number and I am getting rather cranky.

As has been noted, the creosote doesn't travel very far horizontally in the soil, primarily just downward. The goal then is simply to direct it as far as possible away from the area the edibles are growing.
A heavy mil plastic wrapped on the inside and underside should result in it all leaching along the outside of the bed, but the plastic isn't going to last forever so will need replacing every few/several years.

My own anecdote with RR ties: At a previous property the previous owner made some ornamental beds framed with RR ties and the grass wouldn't grow within four inches of the ties. At my current home my veggie garden area is bordered with RR ties and then within that area I have a shed, sand box and raised beds. The grass grows *inside* the holes/cracks in the ties.

In other words there appears to be a big difference between ties in terms of how much leaching they are going to do and the impact this will have on plants (and presumably people).

Dang Albert, I never lived in such a house I'm only 34 and I list many worse problems than that. Actually, I'm not even certain I'm 34, I seem to have already forgotten to count since only a few months ago I thought I was only 32.

If it's true old RR ties, that have been in the ground 40 something years, the leachable creosote is long gone.

If they are fresh, then you have a problem

The solution of bioremediation on sites with large deposits of creosote is to add lots of organic matte to the soil, so if bioremediation works where large deposits od creosote are in the soil, would not the same thing happen in your garden?
The major problem you will have, if you have a good, healthy soil, is burning yourself when you make contact with those RR ties.

Where once RR ties were treated here is now an EPA cleanup site. That should be reason enough not to use them or even take them out if they are being used. Our local dump won't take them. They require special disposal.

Here's another reason not to use them that most people don't think about. The RR uses brush killer spray to keep the right away clear. A thirty year old tie has had a lot of spray on it over the years. That can't be good.

Oosul, I notice you live in Arizona. With that kind of heat your garden will smell like a RR freight yard with all that oozing creosote that tracks all over.

Going cheap can be costly. I'd get rid of em' ASAP.

I have them around my 3 acre yard, delineating a flower / shrub / tree border. They ooze goop and stink the first year. They bleach out and most turn bone white pretty quickly, most of mine have been down 5 - 8 years now. I've never witnessed any effect on the plants, and now there are ants living in some, weeds growing in others.

They are also very, very, heavy, and getting clipped in the chin or shin by a hand dolly carrying a 400 lb creosote soaked, 9 1/2 ft length of oak RR tie is a memorable experience.

I have seen 8' 4" x 4" garden timbers that were less expensive, treated with something far less noxious, and bolting a few of those together might be a better way to go.

Photo of persons who just learned they ate food grown near railroad ties.

Here is a link that might be useful: {{gwi:156818}}

I've never used them and don't plan on it, but isn't creosote the same thing that builds up in chimneys from burning wood?

Photo of persons who just learned they ate food grown near railroad ties.

They are kind of hot, what's your point?

It won't hurt you no more than than the chicken meat they sell at the market.

If you want to be government 'certified', then yeah, you got a problem.

I burn them in my wood stove, but won't put them around my veggies. I will use sevin dust on occasion.

My opinion?

It won't hurt you much if they are old. The leaching is done.

If it is oozing tar - it is bad.

If it is green wood (treated) - it is bad.

If the worms start eating it - it is good.

I used them when I first started with raised beds, but stopped when I find out how bad they can be.
I agree that old ones have stopped leaching for the most part.
I think you should use the landscape blocks, they are in colors & only $2.00 or so each.

Even if railroad ties leach into the soil, it does not mean creosote will be taken up by the plant. Further, the stuff is not that soluble. If it breaks down to smaller molecules solubility can be enhanced, but it does not mean the plant will take it up or metabolize it. I'm using really old ties in our garden and I'll analyze some of the produce for such compounds after the first harvest.

I once lived in a house made of railroad ties put together like a log cabin. I was there for only ten years. Now, hardly a half century later, I have to wear glasses, have a ringing in my left ear, have lost four teeth and a fifth must be extracted, my joints are stiff after gardening and I cannot sleep more than six or seven hours. Proof I should say that one should avoid -- what were we discussing?

Even if railroad ties leach into the soil, it does not mean creosote will be taken up by the plant. Further, the stuff is not that soluble. If it breaks down to smaller molecules solubility can be enhanced, but it does not mean the plant will take it up or metabolize it. I'm using really old ties in our garden and I'll analyze some of the produce for such compounds after the first harvest.

albert 135, sorry for your trouble, but I am not sure all of your problems can be from creosote or the log cabin.
I still think rocks & blocks look better & last longer.
Hundreds of years longer, I hope my grandchildren will garden in my raised beds with the rocks & blocks.
The figs,blueberries,raspberries,blackberries,apples,pears,grapes,plums,mulberries,hickey nuts, butter nuts,gooseberries. And a flower garden to sit in also.

These are pretty old posts but I hope some people will benefit from this info Between 1990 and 1995 I literally handled over 1,000 RR ties while working for a landscaper. We used over 700 just for one project. I wore gloves but still got a light rash inside my forearms from time to time. It completely went away in a couple of days. I guess we had used them so much that it didn't even occur to me that using them to border my vegetable garden in 1997 could be a bad idea. But after about 10 years had gone by, I was just casually discussing RR ties and creosote and I realized what I had done. So I began researching and investigating the problems of using RR ties. Grass, weeds, and ant hills have grown right up next to them from the beginning. A momma Gopher Turtle made her home under one of the beds with the entry way right next to a tie. That hole has been such a nuisance . I filled it in many times but finally gave up. She would have the hole opened back up by the next day. She wasn't causing any problems as long as I didn't accidently step in the hole. And we really enjoy watching her and her babies crawling around the yard.Nearly every source told me that since they were old used ties to begin with, and I had already used them for 10 years myself, there would be nothing left to leach. So I left them there. My family has eaten a lot of delicious vegetables from that garden over the years. I haven't used any RR ties or utility poles since. But that's not to say I will never use them again. Just not anywhere near something I'm going to eat. I feel like I am already the test dummy for creosote. I'm not going to push it any further. I hope this is some help to people that are concerned. I'll gladly answer any questions that I can.

They clean up creosote spills with bioremediation. Add bacteria, fungus, other organic matter and let nature take its course.

I'd think that a garden bed, delineated with old RR ties, then filled with soil rich in organic matter, kept moist, etc. would come pretty close to the definition of bioremediation. I suppose one could procure the special anti-creosote bacteria mix the pro's use and add that, or figure that within a few years, what is already there in a normal garden soil will manage to deal with it. After all, as pointed out above, this is a garden growing something, nor a compacted, graveled, sprayed-to-keep-weed-free RR right- of-way.

My beds still look just fine, bleached-white 20 yr old RR running around.