Raised Garden Beds

[bennylaird]

I'm looking at putting in some raised garden beds and after timber to do the job.

I'm inclined to use the redgum "sleepers" you see in most garden places and Bunnings. Looking for the best value. Again looking for help finding a good supplier at a reasonable cost in Melbournes West.

Would prefer real Sleepers but they appear overpriced.

[namtrak]

Whatever sleepers you use, they can be expensive.

I would be wary of the red gum sleepers given that they will rot with time and will also attract termites. At least use steel for your posts.

Have you considered blocks? Or maybe treated pine, which - and this is the case with the red gum will also distort out of shape over time, particularly if they are only a small bed with no real pressure on them.

You could treat the redgum ones with creosote or sump oil (but I didnt tell you that)

Cheers

[Clinton1]

How many do you need Benny, this greatly affects price (up to 50% off)

[bennylaird]

Am having a bit of a rethink as I was heading down this path but might try a more lasting bed construction.

This is my Sister's Sister in laws..........

[LineLefty]

Holy chokoes! Thats a serious vegie garden

[bennylaird]

Yep mine will only be about 1/3 that size.

[goodwoody]

Go for the treated pine. Easy on tools and lasts just as long as treated h/wood.

[echnidna]

Treated pine is ok for flowers but I wouldn't use it for veggies in case the veggies suck up the arsenic which is an accumulative poison.

[Eastie]

So I take it you don't drink wine, the grapes of which are mainly grown on wires supported by treated pine :rolleyes: Must be laced in arsenic... (albeit insoluble pentavalent arsenic which is not readiy accepted to be carcinogenic and, if it leaches at all as a result of insuffiecient chromium to fix it in the treatment preocess, leaches at a rate that generally sees the levels in soil only micrograms higher than background levels - you'd die sooner from eating almonds, smoking, drinking or living a high stress life with no time to get out and grow vegies).

[rick_rine]

Am having a bit of a rethink as I was heading down this path but might try a more lasting bed construction.

This is my Sister's Sister in laws..........

That is a very impressive garden .
All my beds are raised and I used concrete borders , only 75mm wide but about 350mm high . Its really quite simple and lasts forever . The advantages are less bending into a raised bed and concrete holds the heat so your soil temperature , more important than air temperature , stays high . It is a great heat bank . I used plywood formwork and pieces of electrical conduit to hold it apart , then holes drilled in the ply to line up with the conduit and coach bolts through that to prevent it spreading when poring in the concrete . F52 mesh is more than enough . The form work was then moved along after 1 or 2 days . The same tecnique I used to build some of my farrowing pens . 6:1 concrete mix is ample .

Worked for me .


Regards
Rick

[gazaly]

H4 treated pine, will outlast the garden. 1000's of wineries can't be wrong hey Eastie!

[FrankS]

Am having a bit of a rethink as I was heading down this path but might try a more lasting bed construction.

This is my Sister's Sister in laws..........

WOW!! That is an impressive garden. I too want to build raised beds (cain't bend too fer these days). I'll only need "sleepers" for 2 beds about 3mx1.5m...for vegies only. I can get regular used sleepers from Queensland Rail but they are too big. I wonder, are there other sleepers sort of the sizes used for cane train tracks and where would they be available. The leeching of chemicals from timber poses a real problem. I'd hope whatever I use would outlast 30yrs...I may not want to band at all by that time.
Cheers

[Clinton1]

From what I remember the cane rail lines use the same sleepers as normal tracks. In Melbourne they sell "garden sleepers" that are 200mm x 50mm, a lot smaller than the rail ones.
As for chemicals leaching - you are probably right, so raw timber should be good, or at least the piece of mind will be good :D
If the $ are a bit much now to do the whole lot, leave the uprights that you will use to bolt the sleepers to at the envisioned height. Each year you can add a row of sleepers. The uprights can be the same sleepers as you use for the surrounds.
I did my veggie garden over winter, and I'm still going out every day to check on my potatoes and all the rest. Feels good for an ex-Qld ex-country boy.

I still like Rick's idea of cast concrete though, seems a smart choice if you have a concrete mixer.

[rick_rine]

Thanks Clinton for your vote but really you dont even need a concrete mixer , it is really small amounts of concrete involved and a wheelbarrow is easily big enough , just 3 or 4 barrows will go a long way , maybe as much as a 6m stretch . It is only 75mm x 350mm .
And it is cheap . 0.026 cubic meters to the lineal meter . It is nothing . For the garden bed I had a 150mm wide by 75mm deep footing .

Regards
Rick

[goodwoody]

I would have to disagree with the comments about leaching as the chromium ion acts as a mordant between the arsenic and the cellulose structure of the timber. So therefore the arsenic is chemically bonded and will not leach into the surrounding soil. As for raw timber sleepers, how long do you expect them to last in the ground with excessive moisture from constant watering of the vegies.
I think we should be more concerned about genetically modified foods!

[Eastie]

here here...

Occupational Exposure Standards:
Arsenic 0.05mg/m3 (contaminant in air)
Chromium 1mg/m3 " "
Copper 0.5mg/m3 " "

From what I've found the levels of exposure from directly breathing in CCA wood dust, when analysed by Inductively Coupled Argon Plasma Atomic Emission Spectroscopy (say that in one breath), CCA wood dust exposures of upto 10mg/m3 (twice the recommended exposure limit for softwood) equate to levels of copper, chromium and arsenic less than 10% of the OES (>0.005 mg Arsenic, >0.1 mg Chromium and >0.05 mg Copper - all as time weighted averages given cutting H4 treated pine for 8 hours straight). Current research into leaching is finding similar ultra-low rates from properly treated timber.

Look up the CSIRO website and see what they say about the risks.... For those with an eye for stats see below - from only 7 results of cca wood dust exposure >5mg/m3 these are the results for arsenic and chromium (in mg/m3) .

NZ has it right by not blindly following the US like sheep

[FrankS]

Thanks for all the input and after reading replies to my query I think I'd like to go "au naturel" i.e. timber of sorts. Being in my mid-70's and with an unstable back, I want something that we can just grow some of the most used staples...tomatoes,lettuce, beans, strawberries, etc. It's my belief that a little garden has more therapeutic value than anything else...get your hands into the Mother Earth.
Thanks

[Clinton1]

Sorry to all the Treated Pine advocates - right or wrong its a comfort level thing with me. It just feels wrong. I might well be completely incorrect however as it makes me feel uncomfortable, I avoid it.
One thing my wife taught me was that it doesn't need to make sense when its a "feelings" thing. :D
As for untreated red gum in contact with the ground - my house has a lots of sleeper edging that is 14 years old, and it is still going strong. So I'm happy about that. The rot mainly gets into any surface defects, I reckon if you sealed them it might be worth it.
As for termites - guess I'd better use treated pine woodchips instead of wood chippings as the mulch too hey.

[Clinton1]

Eastie - I didn't understand any of that - its an ignorance thing on my behalf. What did it mean (in simple terms please)?

[bennylaird]

Another working bee saw my sister get a good start on a new garden.

Funny I don't seem to have the same landscape views?????