Topic: capillary matting and greenhouses

[gwynleg]

Hi - I have used some capillary action matting in my coldframe - it was a kit thing I brought cheaply with a tray underneath which holds the water. It has been really good - holding the water for 2 weeks. I want to do the same on a bigger scale in the greenhouse as I can only get up there a couple of times a week.

Probably daft question: I have two shelves which I could put potted plants on. Do I need to put the capillary mat onto a tray or could I put polythene only onto the shelves under the matting? Would that hold the water?

Hope this makes sense. First year of having a greenhouse so very green
thanks

[chriscross1966]

You can link trays with wicks of capillary... I did it last year and it worked ok.... look out for the trays designed to act as saucers for grow bags.... certainly the ones I've got (Sankey IIRC) ar the same size as four standard seed trays side by side.... very very useful....

[Vinlander]

I use heavy polythene - damp-proof membrane - and it's fine.

It's not that difficult to make a long wooden trough and line it if you get the folds right (I like to have at least 3cm of water in the trough, with the mat supported at least 1cm above that on a platform made of old slates - they are the same width as a standard tray).

A couple of inverted 5l water containers will keep 4 or 5 trays of plants going for a week in the hottest summer. Saw cuts in the necks will let the air in and the water out - best they are slightly different heights.

Cheers.

[tim]

Not exactly an answer, but thought it worthwhile to include.

Our 6'x3' bench has 2" polystyrene - (a heat mat) - a membrane - capillary matting - and 2 water tanks at one end.

Capillary wicks give a 4" lift onto the bench.

[gwynleg]

Thanks all
have installed matting into the greenhouse and to my lovely new cold frame (OH doesnt like digging etc but is happy to construct things - which makes me happy!).

Hoping this will all work well now - very exciting
thanks again

[brown thumb]

this is probably a stupid question but if u have constant water touching the roots wont the plants drown

[tim]

No - it's not so much 'water' as the 'moisture' the plant needs.

There is no 'free' water.

[Hector]

I use heavy polythene - damp-proof membrane - and it's fine.

It's not that difficult to make a long wooden trough and line it if you get the folds right (I like to have at least 3cm of water in the trough, with the mat supported at least 1cm above that on a platform made of old slates - they are the same width as a standard tray).

A couple of inverted 5l water containers will keep 4 or 5 trays of plants going for a week in the hottest summer. Saw cuts in the necks will let the air in and the water out - best they are slightly different heights.

Cheers.

This sounds great but I can't quite visualise how you do it, can you describe it a wee bit more as I'm being a bit dense :)

[tim]

Bit different, but this is my way. Same principle.

Those are 1gal tanks on the left, but they could be any size.

[Vinlander]

I use heavy polythene - damp-proof membrane - and it's fine.

It's not that difficult to make a long wooden trough and line it if you get the folds right (I like to have at least 3cm of water in the trough, with the mat supported at least 1cm above that on a platform made of old slates - they are the same width as a standard tray).

A couple of inverted 5l water containers will keep 4 or 5 trays of plants going for a week in the hottest summer. Saw cuts in the necks will let the air in and the water out - best they are slightly different heights.

Cheers.

This sounds great but I can't quite visualise how you do it, can you describe it a wee bit more as I'm being a bit dense :)

You need a thick plank (15mm +) a touch wider than a standard tray - and as long as you can fit in. It's not going to get wet so blockboard or OSB is OK, though I wouldn't use chipboard or MDF because the tiniest splash can ruin it.

Then get some thinner planks that are 100mm wide (I use tongue and groove cladding) and screw them to both sides and the ends so you have a long trough. It doesn't matter if there are lots of joins because you are going to line it with polythene.

Practice making little paper troughs from spare A4 until you are sure that all the folds rise right up to the top at 45deg so the water can't get out.

Use thick polythene (DPM) to line the trough. The folds will need pinning in place at the very top. Drawing pins are adequate.

The trough will be VERY heavy when it has 3-4cm of water in it, so make sure it's supported at every 60cm or so on very strong supports (I use bricks stacked one on another).

Get some old slates or anything else rot-proof that is the same width as the trough (or glass, perspex, Upvc), and make a platform inside the trough by putting them on rot-proof supports that are say 4-5cm high. I used bits of polystyrene foam cut into beams - it won't float float off when the slates are on it. Don't make it a tight fit - the water needs to move through. I also used the plastic from fax rolls once - so old waste pipe will be good.

If you are going to use bottle feed (budgie waterer) then you need to leave spaces one end  of the platform to fit them in (or both if the trough is very long).

Cut your capillary mat so it can drape over the long sides of the platform into the water (right down to the bottom). It doesn't matter if it's in pieces, as long as they but-up neatly and have their own drape into the water. You need to put an agri-textile cover on it anyway or else roots will find their way into the mat and clog it.

Does this help?

Cheers.

[Hector]

Many thanks for this. I've been really worried about watering plants whle I'm in my caravan...so this is super.

[brown thumb]

so basically you have a trough of water some thing being used as i wick raised above the water  so the pots are stood on this and the roots are above the water line and the water is drawn up when needed through the wick ive always been weary of using saucers be neath any pots always left them to drain but will try this method 

[Hector]

I have some tomatoes growing in open-bottomed pots resting in clay granules in those long growbag trays. It lets me add a wee reservoir but not enough if we are away for a long weekend or of the weather is warm. Any ideas how i can adapt the capillary approach for this set up. I can't remember what the open bottomed pot thing is called...senior moment :)

[Vinlander]

By open-bottomed pot do you mean the open-bottomed bottle (usually) that is used as the water reservoir? (like budgie waterers) - or something else?

Granules and the like actually operate mainly by capillary action when the water level is below their surface - until the roots escape the pots and find their way directly to the water level (isn't this a good reason to use capillary matting instead?).

If you can work out how low the water goes before the granules' capillary action gives up then you can arrange a 'budgie waterer' reservoir system to maintain that level (the key point is the place the air gets into the bottle to let the water out) - but you will need a bit of spare tray where you can dig a hole in the granules to fit in the reservoir.

[Hector]

Thanks Vinlander :) The tomatoes are growing in a ring culture wayy. I have trays with the clay and on top of them are compost filled puts with bottoms cut out. So feed at top and water into the tray? I think its supposed to encourage a strong root system. It worked really well last year (Thanks Teegee for advice). I've already got the pots in place or I would have tried capillary matting.
My physics is a bit ropey but with the chicken/budgie waterer..i it the case of sinking into the granules I already have and it wont totally drain away?