Building a large planter (how do I drain it?)

[maf20]

Evening all

I'm builiding a large planter box tomorrow which is 2.4m long by 0.6m wide and deep. I've got no problem building the frame. However, with it being so large I'm not sure how to ensure it drains away. Everywhere I've read it says to use a liner (with drain holes) which is fine. With it being so large and heavy I can't build it so it's off the floor as it will break with the weight. So, I'll need to ensure that it drains away whilst the whole of the flat bottom is flat on the floor.

Any ideas?

 

[Thermo]

whats it sitting on?

 

[LeadFarmer]

Im also about to build a large planter.

You could stand the planter on pieces of slate or roof tiles so that it is raised from the floor slightly, enough to allow air to circulate underneath. Spread the slate so that it fully supports the bottom of the planter. If it just sits on wet ground then it may rot quicker. And drill plenty of drainage holes in the bottom, and paint the insides with plenty of wood preserver.

I plan to line the sides of mine with some polystyrene for insulation, and then line the polystyrene with plastic sheeting. Then cut slits in the bottom for drainage.

You can often find slate in builders skips outside peoples houses, if they are having roofing work done. Then you can become an official skip rat.

 

[maf20]

Thermo - This is what I'm after. With it being so large I was initially not planning on sitting it on anything other than the floor. I've now realised that this isn't the way forward. What about a load of bricks? I've calculated that it's weigh about 0.8-0.9 of a tonne when full

LeadFarmer - that sounds like a lot of insulation. The wood I'm using is already pre-treated would that not be enough with some polythene liner?

Thanks guys

 

[LeadFarmer]

LeadFarmer - that sounds like a lot of insulation. The wood I'm using is already pre-treated would that not be enough with some polythene liner?

Thanks guys

I never fully rely on the qualities of tanalised/pre-treated timber. I dont think you can go far wrong by putting more preservative on, just to be safe.

Im sure bricks would do the trick. You could always inset them slightly, and put a fascia board over to hide them if need be.

 

[r896neo]

Fill the bottom foot of your planter with clean stone then put your liner onto this as it will take mega weight without settling and it will drain freely and easily.

 

[LeadFarmer]

Fill the bottom foot of your planter with clean stone then put your liner onto this as it will take mega weight without settling and it will drain freely and easily.

Good idea. You could also fill the bottom fot with pieces of polystyrene to bulk it out, then soil on top. That way you dont need as much soil and it wont be as heavy.

 

[Thermo]

Thermo - This is what I'm after. With it being so large I was initially not planning on sitting it on anything other than the floor. I've now realised that this isn't the way forward. What about a load of bricks? I've calculated that it's weigh about 0.8-0.9 of a tonne when full

LeadFarmer - that sounds like a lot of insulation. The wood I'm using is already pre-treated would that not be enough with some polythene liner?

Thanks guys

but what is the floor????paving, earth???

insulation isnt needed around a planter, decent soil will do that job

 

[maf20]

Ah, Gotchya!

It's paving Thermo

What's with all this polystyrene? Are you saying to put a flat layer of it in the bottom (and sides), with holes and then soil on top? Must admit I never thought of that. It would certainly protect the wood wouldn't it?

Also, I can't think of any polystyrene shope near me! I'm presuming the usual B&Q etc..?

 

[r896neo]

Where has this polysterene obsession come from? A planter does not need to comply with building regs????

 

[Thermo]

take a couple of paving slabs up or drill some weep holes in the face of the planter. to be honest a planter that size isnt going to have a massive issue with drainage

 

[LeadFarmer]

I guess I need to explain my obsession with polystyrene

When planting up a plant pot you would normally put some stones or similar in the bottom, to stop the drainage hole clogging with soil. Pieces of broken up polystyrene do the same job but are much lighter.

In a really large planter, you can but broken up pieces of polystyrene in the bottom to bulk it out, reducing the amount of compost needed. And assist with drainage. And as its lighter, maf20 can reduce the weight of of his planter.

Im planning to line my planter with some sheets of it, to help with insulation, and keep the soil away from the timber.

And its free! Think of all the polystyrene packaging you throw away.

Oh, and did I mention I like using polystyrene?

 

[Thermo]

yep understand it for the drainage but no need for the insulation

 

[LeadFarmer]

yep understand it for the drainage but no need for the insulation

Point taken, but as ive got loads of it saved up in my shed I ought to put it to some use

maf20, have you made your planter? Any photos?

 

[maf20]

I'm about half way through after this weekend. I was hoping to finish it today but it P****d down from lunchtime onwards. I'll chip away at it over the next few days if the weather stays dry!