Using soaker hose

[Chris J Dixon]

I have, with some success, been using a porous hose to water some of my flower beds, as they are rather dry because of clay soil, a neighbour's ivy hedge and trees in both gardens.

The side border is about 1 m x 8 m, leading to an area of about

20 sq m across the bottom of the garden.

I currently feed from the house, via a pressure reducer and timer, to both ends of what is essentially a loop, down the side border, leading to meanders to cover the most distant area. Naturally, the pressure, and hence flow, drops off at the end of the run.

As some of the hose is now a little _too_ leaky and fragile if jointed, I am looking to replace it this spring, before everything bursts into growth.

Something tells me that there ought to be a simple way to work out how to get best coverage (some sort of resistor calculation?). I guess a separate feed hose with reduced flow resistance, supplying sub-sections, might be the way, but I fear the maths might point to many short stubs, which means more joints and leak opportunities.

Chris

[newshound]

One complication in trying to calculate it formally is that the flow rate, and hence velocity decreases the further you get down the line because of the deliberate leakage. And that will affect the pipe friction (or pressure loss). You could investigate this with a simple pressure gauge. With it running, if the pressure at the far end is similar to that at the start, then it is not much of an issue (and vice versa). Another factor is that the permeability of different sections of pipe may vary from manufacturing variations.

If you identify "dry spots" either because of this factor or because you are at the end of the run, you could increase the porosity of these bits by applying pointy objects. You might need a bit of trial and error to find the right hole size. (I once manufactured a "sprinkler" system based on a flat spiral of hosepipe, with regular drillings of around

1/16 inch made using a cordless drill).

[Peter Burke]

Chris J Dixon [e-mail]> wrote in news: [e-mail]:

I have treated 2 similar situations differently:

One with soaker hose running at (decent) full mains pressure suffering the same problems I split one 35 odd metre length into a 20 and 15 by feeding the centre point using a hose via a T which solved the balance problem.

The other I used a 12 or 15mm pressure reduced irrigation system backbone with drip and spray irrigator spikes off short flexible stubs. V effective as watering and flow could be targeted to areas that needed it most and I felt this was the neater and possibly longer lasting solution.

I can look up sources if it would be useful.

[Chris J Dixon]

I'm reasonably familiar, thanks, I have such a system for my pots and hanging baskets, which also extends to a few plants in another border which need the water.

Certainly worth consideration, but the general advice seems to be that soakers are less wasteful than sprays. (Until they split and you have a paddling pool.)

Chris

[S]

I have designed several soaker hose systems keeping an eye on pressure drop and volumetric flow rates.

I have two currently in use.

One is for a greenhouse fed by 25 mm MDPE water pipe.

This is used for strawberry pots and then tomatoes during the course of the year.

There is a stop valve followed by a watering timer that allows you to set the frequency of the watering (4 times daily, twice daily, once daily, every other day etc) and the duration of the watering ( 1 min, 5 mins, 10 mins, 30 mins and hour). They are cheap at arounds 15 quid.

Then there is a venturi based dosing device.

I can connect a fertiliser bottle via a stop tap for the weekly feeds to the strawbs or toms.

This then feeds an equal Tee.

There is a hose pipe that runs round the perimeeter of the greenhouse and both ends are connected to the one equal Tee piece.

Think of this as a water version of an electrical ring main.

I have put in a Tee piece for each pot on that watering ring main, keeping the ring main loop as it is.

I then connect a short length of hose pipe, followed by a stop valve and another short length of hosepipe right down to the pot from that Tee piece on the ring main.

The stop valve is to turn off water to the one pot once the plant has finished fruiting or has died or is not needed.

You could conceivably use the stop valve as a crude "balancing" valve not unlike the lockshield valves on radiators.

The end of this hosepipe then feeds another Tee piece. I then cut a length of soaker hose to just fit the inside of the pot at soil level and connect both ends of the soaker house to the one Tee piece at the end of the hosepipe.

Thus, by custom fitting a circular soaker hose pipe round the plant, you "focus" the water onto that plant and as the active length of teh soaker hose is less, you get better pressure distribution and more even flow rates around the pots.

This has the capacity to water 30 pots with the greenhouse.

Its getting late now so tomorrow I will describe the system I use for my outdoor veg patch.....

Prod me if I forget!

[Chris J Dixon]

I'd be interested to read it.

Chris

[S]

OK, I have a veg patch. with a 25mm MDPE blue pipe water supply to it.

This is then fed into a 5m long 22mmm copper tube that runs along one side of the veg patch.

At approx 30 cm intervals, there is a reducing Tee like this:

so I have a 4m long "manifold" with 14 of these and the last tee is one of these

then there is a 25cm long 15mm pipe stub at the end with a 15 mm elbow and a 2nd pipe stub.

Immediately after each Tee there is a washing machine valve like these:

wiith a short 5 cm long 15mm pipe between the Tee and valve.

Then at this point, I fit either one of these depending on what I am growing:

for something that needs irregular watering or is influenced by the weather conditions

or

for regular watering, one of these:

The beauty of this is that rather than have the veg patch watered all in one go, I can stagger the watering across the patch to avoid low water pressure problems

So carrots at 6.00 am daily, radishes at 7.00 am, spring onions at 8.00 am etc

Then after each count down timer or electronic timer, I fit one of these:

then a hose pipe connector:

then a soaker hopse length is attached to this, and a stop end put on the other end of the soaker hose.

So its effectively a zoned watering system designed to water veg that are grown in rows like carrots and other root veg.

I do have some fruit bushes, and this is watered uysing the topology I described for the greenhouse.

I'll try and put some images up on a free image hosting website and post them later....

[Thomas Prufer]

I'd would have thought so too, but: The soaker hoses in a fairly hard water area became less and less even in their soaking. They were left in place for a few years, year-round. (These are the kind made of a sort of porous rubber mass.)

I assumed that the pores were clogged with limescale and/or silt from the outside. So I wrapped them around a smooth metal post and pulled them back and forth, thus stretching and kneading the hose, while it was hooked up to the mains with the restrictor disc (washer with a small hole) removed. This made a dramatic difference in the amount of water the hose dripped, and it became much more even.

So the resistance is not time-invariant here:-)

Thomas Prufer

[Chris J Dixon]

As I have been looking at options online, I have discovered another possible way to do it.

I hadn't previously come across Pressure Compensated drip pipes

Some of the ones available seem to have mixed reviews

Seems that they may be more durable than a porous hose, and less liable to low flow at the end of a run.

Looks like I have a whole new set of variables to juggle.

Chris