opinions please - irrigation types

[Gemizzel]

hi there,

We are currently looking at different types of automatic irrigation for our 12x15 polytunnel.

Is there a better method? Do sprinkler systems work better than soaker systems or vice versa?

We are very new to our allotment so don't have any personal experience.

Any pros and cons would be appreciated.

Will be growing the usual things.. if there is such a thing

TIA

[Kristen]

Sprinklers wet the foliage, that can cause diseases like Blight to get a foothold, and can also increase moulds etc. It can also reduce the temperature on a hot day, but because a lot of the water will evaporate (unless applied at dusk/night) it uses more water, so is somewhat wasteful.

Soaker systems (I presume you mean the likes of leaky hoses?) drip water directly onto the soil, so no waste from evaporation nor any wet foliage issues.

If it were me I would use leaky-hose and woven weed suppressing membrane (such as Mypex) and put the leaky hose under it, and plant through it. The membrane will prevent weeds growing, and keep the moisture in, so you will need less water and save the time that it would take to weed the crop. Planting will be a bit more fiddly though.

[Gemizzel]

thank you for your response. Yes i mean the leaky hose type. I presume it is easy enough to tee off to put the little tubing sprays for any baskets we have in there?

[Kristen]

I presume it is easy enough to tee off to put the little tubing sprays for any baskets we have in there?

Sort of. I expect that "drippers" will be best for the baskets. They need a low pressure circuit, but in other respects its the same type of connecting pipework. But being low pressure I don't think you would be able to run the drippers at the same time as the leaky hose. No problem with two circuits, and a tap to select between the two.

There are battery operated timers that will run multiple "zones", so if you want to automate it to that extent you would be able to have one zone for dripper, coming on a 7pm say, and another zone (or several even ) for leaky hose coming on at 8pm.

[Bigmallly]

As it's on an allotment, I take it you are planning on using water from containers & not from the mains. You will have to take gravitation into consideration as you may not have the pressure required to run certain systems..

[Gemizzel]

As it's on an allotment, I take it you are planning on using water from containers & not from the mains. You will have to take gravitation into consideration as you may not have the pressure required to run certain systems..

We do collect water but the irrigation would be mains fed. I dont want to take advantage of the mains water so it would be on the bare minimum to keep the plants ticking over.

[Kristen]

We do collect water but the irrigation would be mains fed. I dont want to take advantage of the mains water so it would be on the bare minimum to keep the plants ticking over.

Sorry, I'm probably being thick, but I haven't fully understood that

You have rainwater harvesting but want to use mains for irrigation - but only enough for "tick over"?

[Gemizzel]

we are harvesting rain for hand watering. The mains will be used for the irrigation system. Maybe its me being silly and people don't "waste" water by watering too much/too often. I just didnt want to abuse the fact that we have access to mains by putting the system on lots.
its hard to describe my thinking... my trail of thought was if there is a upper and lower watering amount to keep your plants healthy.. then i wanted to aim for the "lower amount of water used" to keep my plants "ticking over" until we can get there to use the "free" rain water to give them a good water.
Hope that makes sense!

[Kristen]

It will be a challenge to water, automatically or even semi-manually, using the leaky hose from the harvested rainwater [if the pipework is "normally" connected to the mains]

It will be a pain (I think!) to hand-water when minimal watering is not enough, from the rainwater storage.

A possible alternative is:

Configure the leaky hose to water from the rainwater harvesting tank

Fill the rainwater harvesting tank from the mains if the level falls, say, "below half full". You could put a ballcock in the rainwater harvesting at the half-way point, or lower even - at the "emergency level" - so you would use rainwater when available, mains at other times.

Make sure you get leaky hose that works with low pressure (suitable for water butt) and ditto any automatic watering time-clock - some of those require high pressure mains to make the valves close properly.

This would only get you watering by "gravity", so unless your rainwater harvesting tank is high up this won't work for hanging baskets.

If this is on an allotment they might not allow you to direct-connect your irrigation system to the mains water supply (many allow you to fill a tank with a hose, but not to run e.g. a sprinkler direct from the supply).

If you need "power" to lift the water up to the hanging baskets then you'd be looking at a leisure (car) battery, a small pump and a solar panel to recharge the battery - some cost and faffing about involved with all that

[Gemizzel]

we are allowed to use the mains, I just didnt want to look like i was taking advantage iykwim.
Maybe I'm just being over cautious

Thank you for the suggestions, its defo something we will look into, free water is always going to be the better option where we can

[Bigmallly]

The only time mains were allowed to be used on my old site was to fill water butts only. Best confirm before you start rigging up timers.

[bravo2zero]

Why do want auto irrigation?

[eccles_angus]

Anybody made use of one of those solar "fountain" pumps? They are too weak for much of a fountain but they might provide enough oomph for a relatively large drip irrigation loop? Best part is that it will automatically increase the flow rate when the sun shines, and turn off at night - no need for a timer.

[Philthy]

Make sure you get leaky hose that works with low pressure (suitable for water butt) and ditto any automatic watering time-clock - some of those require high pressure mains to make the valves close properly

Good tip. I bought a Hozelock Aquapod greenhouse watering kit earlier in the year (for anyone unfamiliar it's essentially a connecting hose to a water source that feeds into a plastic 'pod'. From this up to five separate dripper hoses can be extended outwards up to 1 metre each, to water containers, trays, beds whatever). Anyway, I bought this kit wanting to run it off a waterbutt and through a side window, but it transpired that even though the butt was a 500 L job raised 20cm above the sill of the greenhouse to facilitate a gravity feed, the pressure still wasn't adequate. A bit annoying. Connect to a mains tap though and the kit works fine.

I'd agree that leaky hoses or drippers are the way to go, rather than sprinklers / misting systems. With timers in place, I think hoses are easier to regulate, more effective and economical with water, and cause less problems with excessive wet in the environment.

One more thing, I personally think the irrigation mats that are designed to be laid across a bench / staging, and have pots sit on them, are a total waste of time. The idea is that one end of the mat rests in a container of water, and capillary action draws the water along the mat to the pot bases. Evaporation is a fairly major flaw in the design...

[Kristen]

I personally think the irrigation mats that are designed to be laid across a bench / staging, and have pots sit on them, are a total waste of time. The idea is that one end of the mat rests in a container of water, and capillary action draws the water along the mat to the pot bases. Evaporation is a fairly major flaw in the design...

I have capillary matting on my greenhouse bench, the front edge tucked into a piece of plastic downpipe, attached horizontally to the edge of the staging with 90-degree bends, upturned, at each end and used as the water reservoir.

Two things which make a difference: it is horticultural grade capillary matting - thick, and holds loads of water, unlike the thin flimsy stuff that is also available; it is covered with a micro-pore plastic sheet - this keeps muck off the capillary matting, stops it growing algae, and reduces the tendency for roots to grow into it.

Its been in situ for 3 or 4 years and still going fine. My only criticism is that it is a one-size-fits-all and is definitely too much water for some plants that I have on it (if doing the job again I think I would try flood-and-drain instead). As a time saver I have no complaints - in the morning I empty a watering can into the reservoir, and open the vents which takes just a few moments


Capillary matting and micro-pore installed, pipe not yet in place


Pipe reservoir in place