[Kiwi_Ed]

Hello all,

I did a search but couldn't find this discussed anywhere in precise details:

How long do scaffolding boards last used as raised beds?

We are thinking of building raised beds this year. We have had mixed success with conventional vegetable beds in the last 10 years, but after seeing the garden being completely waterlogged during last summer and even more so during this winter (so great to see the sun in these last few days!) we have made up our minds that we need some raised beds to hopefully get some better drainage in the beds.

We were thinking of using scaffolding boards (about €5 per 8ft length here in West Kerry) but was advised by a guy making polytunnels to use pressure treated 9x2s (€20 per 16ft lengths). This being double the price, but also double the thickness and treated so should last at least twice as long. Looking from that perspective they work out at more or less the same price/year.

Anyway: an obvious downside of treated wood is the possibility of chemicals leaching into the soil and ending up in our food. One of the reasons of growing (some of) our own food is to avoid the food being chemically treated, so this is obviously an issue..

Also spending twice the amount of money at once is a thing to be considered as well.

We have also been thinking about the recycled black sheets called Stockboard. But I don't know the price of those (if anybody knows: I'd love to find out!). This should theoretically last a lifetime..

So to make a long story short(er) and because there are tons of people using untreated scaffolding boards for their raised beds I was hoping somebody would have used them long enough to know when they start to rot in our lovely damp Irish conditions.

[Kiwi_Ed]

Just rang a company selling stockboard: €82 for a 8x4x1/2" sheet

Not going to happen in a while..

[tagwex]

Those scaffold boards lifespan will depend on how hard a life they had on a building site and how they were stored. No matter what timber you get and how much you pay for it and how well treated it is, one thing is guaranteed, it will rot.

Spend the extra and make your beds as in the picture below. done for life. You can thank me in the time honoured tradition!!!

[Kiwi_Ed]

Hi tagwex, What is that made of: concrete?

Thanks!

[Greengage]

4 years 6 months 3 days 14 hours and 58 seconds, How long is a piece of string.
I have some 10 years but it depends on lots of things.

[tagwex]

Yes it's concrete fencing. Cheap as chips!

The posts are known as 'H' posts and the boards are known as gravel boards. Go into any housing estate and you will usually see them. Ordinarily timber panels are slotted into the recesses in the posts which then sit on the gravel boards keeping the timber off the wet ground. Any decent builders merchants have them.

[Kiwi_Ed]

Hello Greengage,
Obviously it depends on a lot of things and it is impossible to tell me exactly how long the boards last. But it would be handy to know what some of the 'lot of things' are..

And Tagwex, thanks for the tip on the gravel boards. I will investigate! We were thinking after reading all the bad prognoses here and on other forums ("it will rot" is the general consensus) of using concrete blocks for our raised beds. The price for those is roughly the same (per length) as scaffolding board would be, but it will last forever!

Only worry is drainage as we wouldn't want to be building a swimming pool. But I suppose with plenty of drainage holes between the blocks and the soil being higher than the surrounding area water should drain away.. (hopefully)

[tagwex]

Water will do one of two things in that situation. evaporate upwards or gravity will bring it down. Don't worry about drainage holes on the sides.

The fencing posts have other advantages too as they can be used for supports for netting or a frame of some sort depending on what you grow. If you use blocks it will be an ongoing job keeping them level and in line if you don't mortar them in and put them on a prepared level surface, it wont look good. With the gravel boards you can put a stop end in the recess and it levels itself.

[Kiwi_Ed]

Hi Tagwex,

I wouldn't know about gravity bringing water down in our garden.. You should see the state it's in at the moment, a natural swimming pool or mudbath would be a better idea instead of a vegetable patch.

I really like the idea of the gravel boards, but even though they are cheap as chips as you say, they are about three or four times the price of blocks and mortar. And as we garden on somewhat of a budget I don't think the funds will allow for that. But with a bit of patience and some mortar I think we will manage!

[Greengage]

A lot ot things.
Temperature, Location, water, soil conditions, Type of timber, Fungi,Insects...
Timber that is constantly dry, or affected only by the small quantity of moisture which it absorbs from the air in damp weather, has been known to last for seven or eight hundred years;
When properly seasoned, it is strong, tough, and elastic; but it does not retain those properties if It is generally used in situations where it is either continually dry, constantly wet, alternately wet and dry, or where it is exposed to heat and continued moisture.When timber is exposed to the action of alternate dryness and moisture it soon decays

[Kiwi_Ed]

Hi Greengage, Thanks a lot for that! That makes perfect sense and unfortunately very similar to what most people say about this: "it will rot.."

Thanks a lot anyway for your insight!

[Blowin]

Have a quick read through http://www.gardenplansireland.com/forum/about6779.html pic included.

I can only suggest that you might like to construct raised beds one at a time as funds permit? But, whatever other factors you consider, timber will rot, as others have said, and then you've got the mess of pulling them to bits to rebuild.

[tagwex]

I see that great minds think alike Blowin!