Thread: Sealing a plant box?

Line it with fibreglass and resin, or maybe the paint on stuff sold for waterproofing fish ponds.

paint the inside with one of the tar waterproofing mixes

or change the design of the box to incorporate joints (like bare faced tongue and groove) that will self seal when the wood swells when wet

I thought the tar might be the easist way out, just wondering if it would be safe for plants though, its not practical for me to use a more labor intensive way to construct the box like tongue and groove as I have to make a lot of them for the least possible cost.

I have made a plant box I lined it with water proof plastic then siliconed around the top so water couldn't get in then drilled holes the same size as the ends of soft-drink bottles siliconed them in put fly mesh on top and siliconed that down so the potting mix could not get through.
Regards Ben

Originally Posted by Crawford

I thought the tar might be the easist way out, just wondering if it would be safe for plants though, its not practical for me to use a more labor intensive way to construct the box like tongue and groove as I have to make a lot of them for the least possible cost.

The easiest way would be to buy some 50mm wide tar backed aluminium damp course material. It cuts easily with a sharp knife and you would fold it in half lengthways to seal most, but not all of the right angle joins and any longitidional joins between boards.

Next choice would be a latex waterproofing paint. It comes in standard white but can be tinted. one coat would almost certainly be enough, just miss a bit in the corners so that the pot drains a bit. The disadvantage is the clean up time

It depends on how you cost your time.
The damp course material would be very quick, and the box would be ready for sale as soon as you put it down
the latext paint is possibly less expensive, but you would have to factor in the cleanup time and the time and space needed while a batch of boxes dried

a bead of silicon in the corners smeared out flat with a finger might be good enough — give it a go

Originally Posted by Bupton

I have make a plant box I lined it with water proof plastic then siliconed around the top so water couldn't get in then drilled holes the same size as the ends of soft-drink bottles siliconed them in put fly mesh on top and siliconed that down so the potting mix could not get through.
Regards Ben

Sounds good to me.

Easy way is get a tube of roof and gutter silicone and do the inside joints.
Regards
John

Hey, went out and bought a tube of silicone and a gun to put it in and got to it, half way through the job the plunger on the gun popped through the back of the tube of silicone and silicone oozed out everywhere , finished the job off by hand with a stick, turned out to be a bodgy mess but I think I'll get away with it, looks like it will do the job , just hope the silicone isn't toxic to the plant .

I have used it to seal the bottom of flower pots that had too many holes and the plants were ok. Let it set for a few days first and it should be ok.

Silicone sealant is expensive. I used bitumen paint on some window boxes I made for SWMBO. It's messy to apply but does the job cheaply and effectively. The boxes were made from cheap form ply and have been outside in the weather for two years with no deterioration to the sealing.
Cheers
Graeme

is that treated pine? if so, would you be concerned with the chems to treat the pine leaching into the soil. I know i was recommended not to use treated pine for that reason for a vegie plant box, but since you aren't eating the bonsai this might not be a prob. Or i was given a complete bum steer by whoever gave me that advice and it doesn't leach, feel free to correct me if this is the case.

Hi, yes treated pine, have had plants in them for years without any problems, don't know if I'd grow vegies in them though
They are constantly flushed with water so theirs no build up of chemicals at all.