Safe timber for raised vegetable bed

[Jim_Nutt]

Hi,

I'm looking at building a raised vegetable bed; any advice on what timber to use? I've read about pressure treated timber potentially being unsafe due to chemicals getting into the soil over time. One solution would be to just put a membrane on the inside but it got me thinking, are there any treatments and/or woods that could be used that are durable not too expensive and don't involve chemicals?

I also came across this, which I believe is sold as a safe treatment for such a project:
https://www.newventureproducts.co.uk/organowood-wood-protection/387-organowood-01-protection

Cheers!

 

[Rorschach]

The reason treatment works is because it is toxic. So either don't worry about it (I wouldn't) or use a naturally resistant wood and replace it when it does rot out.

 

[Glynne]

I used new treated railway sleepers and we’ve been eating all different types of vegetables for over 10 years without any problem.

 

[MikeG.]

.......I also came across this, which I believe is sold as a safe treatment for such a project:
https://www.newventureproducts.co.uk/organowood-wood-protection/387-organowood-01-protection

You know that that isn't suitable for hardwoods? It's in their Data Sheet.

I haven't seen any link to any independent testing or certification, so as far as I can see, these claims of rot protection are just that, claims. So, do you look for a durable hardwood (there are lots), or do you use a vulnerable softwood with some substance which may or not be snake oil?

 

[F Flinstone]

I think you will find that new treated construction timbers are not now treated with toxic chemicals, the old Tantalized "Green" treatment contained arsenic, not good, Cedar has a natural oil the helps prevent rot, old railway sleepers should not be used as Creosote is carcinogenic, and will taint your veg. I have used solid oak which was green, so it did warp and after 12yrs has started to rot. It will be replaced next year with a solid timber of about 200mmx80mm , it will probably be Oak or beech or Chestnut, all of which are freely available from French saw mills, they will be lined in black plastic flooring grade, so there is no soil in contact with the timber, also they will sit on brick or tile base so again no contact, Iam hoping that that will last longer than the first lot.

 

[Woody2Shoes]

Constructional timbers are still treated with pretty nasty chemicals - just a bit less nasty than the ones they used to be allowed to use (I've just had some roofing battens delivered with attached paperwork describing what they're treated with!). I prefer not to encourage the spread of these chemicals around the air/water in the environment any more than absolutely necessary (I never burn treated timber, for example). They may or may not harm humans, but they're designed to harm insects and fungi on which we indirectly depend.

I've used naturally durable timber such as sweet chestnut for raised beds - inexpensive, local (to me in SE UK), almost no sapwood (which is much less durable) - in riven "half-round" form. I've also used oak, again riven half-round. Arguably, riven timber is more durable than sawn. I'd recommend either.

If you want truly indestructable raised beds then use masonry e.g. old reclaimed bricks/blocks or maybe something like Accoya (if you're prepared for the cost!).

Cheers, W2S

 

[Orraloon]

There is always brick, concrete blocks or stone to be sure no nasties get in your veg. The other option is ask if it has to be raised beds or can it be planted right in the ground.
Regards
John

 

[Jim_Nutt]

.......I also came across this, which I believe is sold as a safe treatment for such a project:
https://www.newventureproducts.co.uk/organowood-wood-protection/387-organowood-01-protection

You know that that isn't suitable for hardwoods? It's in their Data Sheet.

I haven't seen any link to any independent testing or certification, so as far as I can see, these claims of rot protection are just that, claims. So, do you look for a durable hardwood (there are lots), or do you use a vulnerable softwood with some substance which may or not be snake oil?

Wasn’t aware of that. Thanks for looking at the detail.