Sleepers for raised beds!

Hi Comrades,
I have raised beds and recently replaced some of the sides with railway sleepers. Unfortunately I think they were a bit heavily treated with bitumen. As a result some of my veg up to about 12" from the have started to distort and develop a crumpled brown mottled leaf. Hopefully I won't have to replace the sleepers but what about the soil? Can anyone suggest a solution?
John

 

How about putting a polythene sheet liner behind the sleepers. To do this you will have to remove a bit of soil - perhaps a trowels width. As that soil has been in contact I would be inclined to get rid of it.

 

Yes good point Peter. I would imagine it would still seap under though. Worth a try anyway. Thanks.

 

John, I would take the plastic as far down as you can. Seepage is through water/moisture and gravity pulls that downwards or horizontally. So you may find that it doesn't seep upwards.

 

Used sleepers are great for retaining soil but not really suitable for food crops. Bitumen, creosote & other unpleasant stuff oozing out, especially in summer. If your veg is shriveling, what's it going to do to your meat? :(

 

meat? someone growing meat in their vegetable plot? hehehe
I would seriously consider replacing the railway sleepers
You can now buy new ones which haven't been treated at all

 

Agree with Tortuosa and Whis4ey, but if you can't change the sleepers then I would use blue DPM polythene from a builders merchant and sandwich a layer of tough geotextile like Terram between the polythene and the sleeper. I would also take the polythene down to at least a foot below the lower ground level (assuming it's soil)to prevent capilliary action bringing the washed in pollutants back up again in dry weather.