Can't think how to make this work (automatic watering of raised beds in poly)

[gardening_gal]

I've got 2 water butts that I'd like to set up so that I have automatic irrigation in the polytunnel.

I've seen the kits with timers suitable for water butts. My problem is one of height.

Because I have raised beds inside the tunnel (approx 25cm high) I need to have the water butt tap raised higher than this (that in itself isn't a problem I can build something for the butts to sit on) but then I have the problem of how to get the water pipe inside the poly at a height above ground level.

The pipe can't just lie on the ground as that's obviously lower than the bed and that will impede water flow but I don't know how to deal with this without making a hole in the plastic cover to feed the pipe into the tunnel in a higher spot, which I really don't want to do.

Not sure if anyone can think of a way round this?

[bearded bloke]

Lay it on the ground gal,all the time that the level of water in the butt is higher than the outlet it will flow by gravity

[gardening_gal]

But will gravity be enough to get the water back up from the ground and over the 25cm wall height of the raised bed? I keep reading stuff about not running water up a slope and here am I wanting it to climb a wall.

If I build some sort of platform for the water butt that's maybe 50cm high, might that be enough to help with this?

I know nothing about this kind of thing. Had you guessed?



Thank you btw, for replying.

[Kristen]

If there is no air in the pipe, and air cannot enter from the low end (a valve / timer / whatever) then the water IN the pipe can flow uphill one side and down the other - outlet end must be lower than the water level in the tank / water butt, but the bit in the middle should be fine - as it will syphon.

So you might have to have the timer thingie at the plant end, not the water butt end.

I think that will work!!

Alternative, perhaps, is to have a higher tank. Pump the water from lower tank into higher tank using a poxy slow low power solar pump. So long as it can lift enough water in a day for the irrigation it is fast enough, so a trickle will do. On sunny days the pump will move more water, and the plants will want more, so the balance will hopefully be OK.

[RaptorUK]

But will gravity be enough to get the water back up from the ground and over the 25cm wall height of the raised bed? I keep reading stuff about not running water up a slope and here am I wanting it to climb a wall.

If I build some sort of platform for the water butt that's maybe 50cm high, might that be enough to help with this?

Water will always try to find it's own level . . . so if the top of the water in the butt is higher than the end of the pipe water will flow, as long as the pipe doesn't go higher than the water level at any point between the tap and the end of the pipe.

[gardening_gal]

Thanks everyone. I'm happy it looks like this can be done ok even if it means messing around with it a little. I don't mind doing that but I wouldn't have liked to try and set something up that was doomed to failure from the start.

I'll go give consideration to where to site the butts now.

[Bill HH]

They are all quite right, it matters not that the pipe is on the ground so long as the tank is higher than the outlet. Mind you the higher the tank the better the pressure will be but if its just drippers i dont think you need much pressure.I dont know how big your tank is but water weighs a lot so any structure to raise it needs to be substantial.

[bearded bloke]

Ere we go GG,the picture shows a domestic gravity system,look at the expansion pipe from the hot cylinder to see how far the water rises back towards the cold water storage tank

[gardening_gal]

I was planning on building it with treated 4" x 2" lengths of wood. I'll have some of this left over after making the poly base frame. (That's another thread, lol.)

I've just been out measuring and I figure I can get one butt either side of an unused (and concreted in) washing pole so I'll build the raised platform round this. That way I can put a ratchet strap around the whole thing and hopefully the fact the pole is between the butts will also help keep it stable during windy times. This means the butts will be at the rear of the poly and out of sight.

The butts aren't big ones to be fair, they are only small ones I got cheap from Aldi or Lidl some time ago. 100l each I think.

I can make the platform 600mm high and the top of the butts still wont be visible over the top of the poly so it should all fit in nicely. Famous last words!

Wish me luck!

[bearded bloke]

As Bill says the higher the tank the greater the pressure,if you need to calculate it,a tank 10 metres higher than the outlet will give 1 bar (14 psi) IIRC.

[gardening_gal]

As Bill says the higher the tank the greater the pressure,if you need to calculate it,a tank 10 metres higher than the outlet will give 1 bar (14 psi) IIRC.

Thank you.

I think I'll just stick to posting 'can I do this' and you all either saying yes or no.

I was never good at maths at school.

[gardening_gal]

Ere we go GG,the picture shows a domestic gravity system,look at the expansion pipe from the hot cylinder to see how far the water rises back towards the cold water storage tank

Ah. I do so much better with pictures. Thank you.

[Bigmallly]

If you have plenty of 4"x2", play safe and fasten 2 pieces together giving you 4"x4". Will be much stronger.

[Bill HH]

Apart from making a stand strong enough to take the weight (and even 100L is heavy) The tanks themselves are most at risk when they are empty from blowing away. Also if you or any friends have childrem make sure the tops are secure, wouldnt want to find a pair of feet sticking out the top.

[Potstubsdustbins]

Everyone is quite correct in what they are saying follow their advice and you won't go far wrong.

One further point each 100lt container when full will weigh approximately 220lbs, make sure the stand you build can take this sort of weight and most importantly that the butts are secure the last thing you want is for a full butt to land one someone.

BB want a job mate?

Potty