Raised beds - help?

Suzy_M

gazzak wrote: »

I went and purchased some pressure treated wood from Wickes at the weekend. Knocked 3 frames up then found out that treated wood will permeate the soil :eek:

Now looking for some plastic to line the wood!

Try stapling a roll of damp proof course to the inside - tougher than plastic so more resistant to tools being swung too close!

lindseykim13

What wood can i ask for or buy in the diy shops that i know won't be treated with anything? will all of the wood for sale be treated or just special types that will clearly say on them? would those slot together types (ones for building sheds) be any good? would get some pallets but couldn't get one in the car anyway. thanks

Davesnave

I built a raised bed with concrete blocks. It takes a bit of time to dig & lay a foundation, but you only do it once! The block building bit is reasonably rapid and needs little skill, just the ability to follow a string line. I screeded mine off on the inside & outside with pond cement render, as I thought the porosity of the blocks might draw moisture out. I also wanted to round off the tops of the blocks so they would be kinder on the knees/legs.

No idea if all this improved things from the moisture retention point of view, but the soil only gets dry & shrinks away in really dry periods. The bed is still there 20 years later and looks like it will see me out!

Davesnave

'What wood can i ask for or buy in the diy shops that i know won't be treated with anything? will all of the wood for sale be treated or just special types that will clearly say on them?'

Floorboards are probably your best bet, secondhand if possible. (Have you ever tried to dismantle a pallet? I have and I found some pretty mean serrated nails that wouldn't pull!) Most wood isn't tanalised and even some sold as gravel boards is just dipped in a relatively harmless dye. Pressure treated stuff that really lasts has arsenic, chrome & copper in it, which does, apparently, leach out. Tanalised timber should be labelled as such & it has a greenish tinge.

divadee

My neighbour has just offered me some spare decking that they had left over, would this be ok for our raised beds?

I had another friend whos a builder that offered me tannelised wood for silly money about 10p a strip , but i dont know what wood to get which out of these 2 would you go for?

Davesnave

Gosh, this has opened up a can of worms! Apparently, there is a new formula for 'tanalised' wood in EU countries, but there is still a lot of debate about the safety of treated timber. For example, see:

http://ro.uow.edu.au/cgi/viewcontent.cgi?article=1045&context=artspapers

I don't know a simple answer. New 'railway sleepers' (not the real, old creosoted ones!) should take a long time to rot, but are hardly money saving. Or perhaps some reclaim. like concrete sectional garage panels or cut down galvanised roofing sheets - hardly elegant & sharp at the edges.....I'm sure someone will come up with something brilliant, but not me.

Perhaps all the plastic flower pots that currently go into landfill could be recycled in the manufacture of new structural board - any entrepreneurs out there?

katyk_2

Hi folks
I am in need of some advice re raised beds as I am hoping to overhaul the garden soon. I need to destrpy the old leaky shed and replace him with a new one and was wondering if the wood from the old shed could be utilised to make raised beds for veg or if the fact that it is approx 33 years old and has been painted goodness knows how often in that time (3 times in last 6 years since we moved in) would render the wood too toxic for the plants?
(Not even sure if individual planks will separate now to be usable)
Thanks
Katyk

Sue-UU

Hi Katy,

I don't see why you couldn't put it to good use still, after all I presume you haven't painted the inside which would be all that mattered, to my mind at least.

If nothing else, I've bumped this thread back up for others to hopefully give their opinions, meanwhile I'll ask hubby in the morning to be sure of his thoughts.

All the best and what a good time for a shed to last!

Sue

katyk_2

Just noticed this thread after opening one myself above. Perhaps my question is better put here.
I am about to dismantle an old garden shed which leaks and had wondered if I could use the wood from it for raised beds (assuming I can get the 'planks' to separate after roughly 33 years.) Trouble is it will have been painted goodness knows how often in that time (3 times since we moved in 6 years ago) and don't know if that would render it too toxic for the plants.
Will only have room for about 4 raised beds of about 10' x 4' max.

Also, when raised beds are in place and I need to fill extra 8-10" do I buy topsoil? Use some taken from where paths are going to go? Fill with compost? Soil here is not brilliant - have had a half hearted attempt at growing last year but think the soil needs a lot of feeding as only the tatties and carrots came reasonably well. Mind you it was a summer of non stop rail too.
Anyway, all sugestions most gratefully received
Thanks
Katyk

valk_scot

katyk wrote: »

Also, when raised beds are in place and I need to fill extra 8-10" do I buy topsoil? Use some taken from where paths are going to go? Fill with compost? Soil here is not brilliant - have had a half hearted attempt at growing last year but think the soil needs a lot of feeding as only the tatties and carrots came reasonably well. Mind you it was a summer of non stop rail too.
Anyway, all sugestions most gratefully received
Thanks
Katyk

Well, remember when you first make a raised bed you need to double dig it and incorporate some manure or very good home-made compost. (Not potting compost that you buy at B&Q...that stuff is different.) Ideally, according to the late lamented Geoff Hamilton, you need one or better two large buckets of well rotted manure per square metre. Just the act of digging plus manure will raise the level quite considerably, and you can add the top couple of inches from the paths. Also dig in some sand (if your soil is heavy) and any other bulky rotted material you can find, like one year old leaf mould.

All of this will have two effects...first it will raise the level inside the beds. There's no reason you need to fill the beds to the absolute brim, btw, and as the level raises quite naturally every year as you add mulches and poultices of compost etc it's actually counterproductive to fill the beds totally in the first year.

Secondly you're adding food, food, food....and improving the texture of the soil by adding bulky materials and breaking it up a bit.

It's a lot of hard work at the outset to make a good raised bed, but it's worth the effort. If you never walk on the beds after the initial digging, you never have to dig them again, not ever. I dug some of my beds 10 years ago and the soil in them is fantastic...rich, crumbly, full of organic matter ad worms.