wood for raised beds

General tips / questions on seeding & planting

Moderators: KG Steve, Chantal, Tigger, peter

paul
KG Regular
Posts: 2
Joined: Tue Nov 29, 2005 8:58 am

I would like to put some raised beds on my allot ment and would prefer not to use treated timber. Larch is often recommended as having reasonable longevity. Does anyone have any experience of this or other suitable wood types? Thanks
User avatar
Johnboy
KG Regular
Posts: 5824
Joined: Tue Nov 22, 2005 1:15 pm
Location: NW Herefordshire

Hi Paul,
The Health and Safety Regulations meant that some time ago the formula for preserving timber had to be reformulated and these treatments no longer contain some of the offencive chemicals used in the original brew. Unfortunately a lot of the Organic publications, whether by error or design, omit to inform people.
I have today consulted a Fellow of the Institute of Foresters on your behalf about the use of Larch.
He explained that the 'Heart Wood' has fairly good anti-rotting properties but the rest is not any more brilliant than normal softwood. He explained that although it is used for fencing it is still normally treated.
I explained your application of it and his words were:- "no guarantee could be given for use in contact with moist soil at all times" - "It may last a little longer but nothing would really be gained"
Asked how dangerous the chemicals used in the treatment are he said "they are safe enough for men to handle without the use of gloves." That, one presumes, is the reason in the formulation being changed.
May I suggest you look up Tanalizing or Cellcurizing being the most widely used methods of treatment used in the country.
I would also advise you that rotting timber attracts an awful lot of nasties especially Woodlice and Keel Slugs both of which can be very bothersome and a whole host of Fungi.
JB.
GeoffPad

We've been using raised beds for quite a few years and usually rely on old floorboards from a couple of builder friends and they seem to have lasted a good number of years. Some now need replacing, having been in situ for about ten years and as we have just replaced a large shed with a smaller one (with the intent on being tidy gardeners!!) we are planning to use the side panels from the old shed in pairs as the raised bed sides. If they last another ten years I'll be happy. I agree with the previous reply about pests living near the wood but our worst problems have only been ants and slightly more slugs than we would have hoped for! Apart from that we have had much better and more crops using deep beds and they are much easier to manage.
jane E
KG Regular
Posts: 369
Joined: Fri Nov 25, 2005 11:00 am
Location: Leics

Johnboy - do you use raised beds or garden on the flat or a mixture? I sow potatoes on the flat and ridge, beans on the flat and other things in raised beds, at moment just without boards. I found weeds more of a problem round the edges than slugs.I've been making raised beds for a disabled friend with floorboards.
What do other people do?

Did you get my email message? Jane
paul
KG Regular
Posts: 2
Joined: Tue Nov 29, 2005 8:58 am

Thanks for the replies. I have looked at Tanalith E (this is Chrome and Arsenic free) and is claimed to be safe to use which I don't doubt. I am approaching this more from a point of 'is this treatment actually necessary' if there is a viable untreated alternative for this application. The HDRA website states that Larch will last for 10 years but I don't have any evidence that that this is true or whether the reality is closer to 2 years. It is interesting that Geoff has used old floor boards which have lasted 10 years (the maximum that I require) and I will investigate this avenue further. Cheers
Guest

heat treated wood from builders merchants, so it is properly dry.

v cheap and v easy

dont go to the dreaded well known names......

Stu
Iain
KG Regular
Posts: 99
Joined: Tue Nov 29, 2005 1:21 pm
Location: Stirlingshire.

I'm currently agonising over purchase of boards for raised deep beds. It might be of some use to give you prices I'm being quoted.
Old scaffolding boards 9" x 2" :

24 @ 8'long
52 @ 4'long
28 @ 5'long

All for £135 delivered from 15 miles (central Scotland).
Same secondhand woodyard offers 7" x 2" x 14' at £3 each.I think they're old floor joists.

I think scaffolding boards are a good option (though the ones referred to above are well used i.e. the plaster with which they were no doubt in constant contact has eaten into and removed the softer fibres to a depth of a few mm. resulting in a sort of wizened surface. but they're sound enough and should last a good number of years, I believe).

Price seems ok to me, but maybe somebody knows better.
Barry
KG Regular
Posts: 350
Joined: Mon Dec 12, 2005 11:18 pm
Location: Central Kent

I have always raided roadside skips for old timber with which to make my raised beds. Forunately, there have been a lot of loft conversions around here and some wonderful roof joists have been available. These are extremely thick and last ages.
However, I recently fished a significant number of roof tiles out of several skips and have used these to create my latest beds. The beauty of them is that they don't rot and do interlock, so last ages and are secure. You have to bury them in the ground, though.
Another technique I have used is to deploy aluminium as boarding. I managed to get four pieces of an old greenhouse base and this has worked perfectly. A fellow skip raider finds all sorts of thin metal sheeting, which also works well. Both the tiles and metal also heat up very quickly, which in the Spring and Autumn is a big advantage over wood.
Chris
KG Regular
Posts: 183
Joined: Mon Nov 21, 2005 8:26 pm
Location: Moray, Scotland

Hello Barry

Good to see you on the forum again with such good advice. I know this may not be the right section to ask a general question - but what do you think of the forum now, bearing in mind some of the old discussions?

Chris
Chris
Barry
KG Regular
Posts: 350
Joined: Mon Dec 12, 2005 11:18 pm
Location: Central Kent

Hi Chris,
Sorry, I don't have as much time as I used to so can't spend hours and hours discussing vegetables on the forum. To date, I have just dipped in and out a couple of times. As a result, I don't have any strong opinions. I didn't think too much of the old Forum, which was slow, kept going wrong and had little structure. At least you know where you are with this one -I think!
doddy
KG Regular
Posts: 10
Joined: Thu Dec 29, 2005 3:53 pm
Location: Chelmsford, Essex

I was lucky enough to obtain a vast amount of timber from a builder friend and I have made 19 raised beds on my allotment. As they have only been in situ for just over a year I can’t comment on their longevity or any unwelcome guests. I do however have some very welcome guests, frogs and lots of them hence, no slug problems just the pigeons, aphids and whitefly to contend with. Nobody said life would be easy.
Allan (Doddy)
Post Reply Previous topicNext topic