On Saturday, 7 May 2016 15:33:02 UTC+1, MM wrote:
I'm trying to set up a home-brew drip feed irrigation kit for 6 tomato
plants. I've already got a lot of suitable tubing, the T-pieces,
connectors, drippers etc. The water feed is off a new 230 litre water
butt to which I have attached a brass tap instead of the black plastic
one. To the tap I've connected a Hozelock electronic water timer
(AC1), which Hozelock customer services confirmed will work with a
water butt, and it does.

So I placed the tomato plant pots close to each other and close also
to the water butt, then ran the tubing from one to the next. I then
switched the AC1 to "always on" for testing.

The problem is that even when the butt is brimful it seems to have
only enough head of water to feed three of the drippers. And even then
the third dripper furthest away from the butt dribbles rather than
drips. The water will just not flow around the circuit to all 6
drippers, and I can't understand why not! I even tried sucking on the
little pieces of tube as if to "bleed" them of air. No improvement.

The feed to the first 2 pots is excellent and the water drips really
nicely. So it would work for 2 plants, possibly 3. But where am I
going wrong? The water butt is mounted on the typical black plastic
stand, which is about a foot off the ground.

MM

You need your water butt to be higher off the ground.
Much higher.
Things will be even worse when it's nearly empty.