Marine grade plywood

[daiviet_nguyen]

Hi,

I have only heard of "marine grade plywood" last week.

Would anyone know of its suitability as grow-box please?

Treated pine boards last several years. But obviously the longer the better.

(I have also made some enquiries for fibre-glass boards, but so far found none.

Also there is recycle plastic board, which has been made into raised-bed for vegies and flower etc. But it is sold in a complete unit for $300.00; not individual boards.)

Regards.

[Bougy Fan]

It is made of harder timber than ordinary ply and waterproof glues. It will last longer than ordinary ply but the expense of it would probaly make it not worth it. I would also be painting it as boats are protected usually with fibreglass and don't sit in the water with bare plywood.

Tony

[daiviet_nguyen]

Thanks Tony.

It would make sense to paint the inside as well. Would the paint affect the health of the tree somehow too, Tony?

And what kind of paint should we use?

Thanks again

Regards.

[reddoggy]

Yes i agree with the other guys, marine grade plywood is made out of hardwood and is only as good as the glues they use to bond it together, as a builder of some 45years experience I have used the best quality plywood and it still breaks down over time especially if it is not sealed every few years, would suggest if you want to use it you could line it with a metal tray or maybe a liquid membrane such as a bathroom waterproofer., but I am not sure how this would effect the tree should be alright because most of them are water based.good luck

[Bougy Fan]

Well if I was going to the expense of making them I would paint them with enamel - and all of the edges before assembly. I wouldn't bother with marine ply - I have made a few from kwilla decking offcuts and they seem to weather OK without painting. They haven't cost me anything except time and they will be turfed out when the are no good.

[kcpoole]

I woud use an epoxy based paint ( 2 pack Paint + hardener) to paint with
any timber Boat uses Marine ply, and is then painted with epoxy and or Marine Varnish.

Both of which are UV stabilised which normal interior paints and varnich are not.

as marine paints these days must not be polluting and not leach bad stuff, they should be safe to use around Plants as well I think.

Ken

[FlyBri]

Gday Daiviet!

My experience with marine ply is that it is very heavy, which is OK if your grow-boxes are going to stay in one place.

I have used recycled Merbau decking to make boxes, and it seems to be lasting fine. Of course, not everybody has access to recycled timber. I would seriously look into WPC (wood plastic composite) decking/fencing as a durable, lightweight and easily machined option - in fact, I am thinking of replacing the rotten hardwood boards on my Bonsai benches with WPC.

Thanks, and good luck!

Fly.

[rawhide]

I use normal pine and paint it with a water sealing paint that you use for lining cocrete to stop it
Leaking .it is used for fish ponds so it is relative harmless I presume I have at least six trees that have grown happily for two or three years in them.

[alpineart]

Hi Daiviet , Marine grade ply is made from certain tropical hardwoods , however all plywood is basically veneered or laminated softwood or hardwood and glued together using Phenol Formaldehyde resins . It is compressed during a process of lamination which impregnates the timber with the resin .High temps/steam are used to expand the fibers as well as high pressure up to 1000 tonnes to impregnate the resins into the timber .This compresses each layer of resin and timber together . Which ever ply you use it will break down under constant moisture and bacterial attack .

I have used form ply which is used for concrete pours , raft slabs and form work . It is or has a water proof coating applied to the exterior however it begins to break down in 12 months when used as grow boxes , it will and can be used dozens of times when used as form work , due to the very short period it is actually wet . Marine ply will no doubt last 3-4 times longer however it is designed to be used in wet conditions . Old ply boats had water in the bulge to prevent them from drying out , It does however suffer from dry rot , that is when moisture is present and then dries out and continues in a cycle of wet /dry .

They local timber mill here in Myrtleford produces thousands of tonnes of form ply and structural ply and uses the same resins as in marine ply . The only difference is the timber is Pine not Tropical Hardwood . Price wise it would be very expensive to make grow boxes out of and the weight factor would and is a big downfall . I have begun to use various size seed trays 350 x 300 x 75mm or tube stock trays 500 x300 x100mm and place a piece of shade cloth in the bottom , in some cases i have screwed 2 trays together if a deeper tray is required and cutting the top piece out to fit the tree in leaving a lip around the top to prevent the mix being washed out . I picked up some large trays 600 x350 x75mm from a Native nursery closing down on Springvale Road Cheltenham a while back , i have used them with fly wire inserts for landscape training trays . Hope this helps

Cheers Alpine

[Luke308]

I have dismantled wooden pallets that I have got my hands on, and was planning on making grow boxes from them. They look like pine, which I assume is treated. I would have never thought that would be an issue though. Can someone elaborate on effects of leaching, and also the cheapest and easiest way around this? Obviously I was thinking it was only gonna cost me a few stainless screws, and some time. Perhaps not

Thanks guys & gals
Luke

[daiviet_nguyen]

Hi everyone,

Thank you very much for the detailed replies.

So my own conclusion is not to proceed with this material due to weight and expense.

As FlyBri suggests, wood plastic composite is something to look into in the future.

You are lucky FlyBri, to have access to recycled Merbau

Hi Luke,

I am just being cautious. I have not read of any instance where paint, etc affect the healths of potted trees.

I am guessing that we can stick to the suggestions above.

Best regards

[Watto]

I use timber from second hand pine pallets. Now this timber only lasts about two or maybe three years and that is the time required for stabilisation after digging so it is just fine. When the box is no good it is time to re-pot - perfect timing. If you want then to last for years, buy a cheap bonsai pot, but if you are growing them on (or they are from a dig) the pine is fine.
Just another opinion.

[Bougy Fan]

Hi Luke I would be very surprised to find pallets were made from treated pine - it would be too expensive and not worthwhile. I have made boxes from left over treated pine palings and have not noticed any leaching problems.

Tony

[Shane Martin]

As Bougy Fan says - I have made a few from kwilla decking offcuts and they seem to weather OK without painting. They haven't cost me anything except time and they will be turfed out when the are no good.

x2 on that. I made around 6 using kwila decking offcuts just before the growing season got underway. End up around the same weight as clay pots, and I think I'll be long gone before they fall apart..... and the best thing is they are way better looking than those ugly white foam boxes I used for the past 30 years.

[bonsaibruce]

Howdy,
Interesting the discussion on paint affecting the tree.
There was a test at Bimer years ago where some copper sulphate was mixed with the paint that was used on the inside of some pots. Trees were fine but there was no roots all the way to the pot. There were no roots that grew in a circle in the pot. We stopped doing it as the trees need re-potting every few years what ever you grow them in. I always considered a wooden grow box to be disposable. Happy bonsai, Bruce