
Drip Irrigation Design Guidelines - bryanrasmussen
https://www.irrigationtutorials.com/drip-irrigation-design-guidelines-basics-of-measurements-parts-and-more/
======
leemac
I have a small irrigation setup that works somewhat well for my needs. I have
a small pond/waterfall pump inside a rain barrel that pushes a decent flow to
my emitters that water my lettuce and cucumber plants. The pump inside the
barrel is connected to an outdoor Z-Wave switch that is ultimately controlled
by my SmartThings hub.

The main downside is it's currently manual and water is limited in the barrel.
The rain barrel can only hold so much water and at times, I find my ZWave
switch will turn off, then back on, which eventually drains the barrel if I'm
away. I usually turn it on/off on hot nights when I'm home so I can monitor
it.

Next summer I'll take a different approach with some of the ideas from this
article. Perhaps use the rain barrel only if it's full (using sonar sensors
that ping off the water level), but use the main house line as the primary.

That hacker/tinkerer in me wants to ultimately build a system that waters
based on weather patterns/demands. I'll save that for next year.

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MrTonyD
This seems way, way too complicated.

Just last weekend I visited a 30 acre University farm - where they teach
agroecology and have graduates worldwide who are running farms. I noticed that
they were just using normal water spigots at different locations on the farm,
and they had timers of different sorts on those spigots to what looked like 1"
poly tubing. When I asked about how they adjusted for all their different
crops, they said they just adjusted the timer for a set of rows and used a
sharp point to poke different sized holes in the tubing at the base of plants.
No big deal. They said it sometimes takes a few adjustments, but it works
fine. The have been doing this successfully for decades. Very easy and very
low cost.

~~~
mmmBacon
So one issue with what you posted is that it's a recipe for contaminating your
drinking water. You need to have some type of anti-siphon device to prevent
the back flow of water from your irrigation system into the house water
supply. My guess is that somewhere the farm you are talking about had a giant
and very expensive double check back flow preventor. Having designed and
installed several irrigation systems I can tell you that pressure drop is a
thing. To get the correct CFM, I had to install 1 1/2" mains so that the rear
of my lot would have enough pressure to deliver the cfm I needed. Also, water
hammer is a thing if you have lots of pressure. Your consumer grade fixtures
will be destroyed by water hammer and your system will need lots of
maintenance. Also, if you live around the system, water hammer is noisy and
when your system trips on at 5am, it's going to wake you up. So while I don't
doubt the farm did this, I'm not sure it's an appropriate installation for a
home owner that just wants the system to work reliably for years with little
to no maintenance.

~~~
djrogers
In California every outdoor spigot has to have an anti-siphons installed
directly on it, so it’s not too hard to imagine that being the case here.

~~~
MrTonyD
And they adjusted for low water pressure by poking a few more holes for each
plant nearer the end of the the poly tube. By avoiding "nozzles" on their
tubing - which would require pressure to operate -- they greatly simplified
the design of their irrigation system.

~~~
mmmBacon
Again anything that moves liquid from point A to point B requires water
pressure or the liquid will not move. So the system you describe still
requires water pressure to operate. I really don't see how this simplifies
because you have to empirically determine the number of holes at each plant.
If you have thousands of plants, I just don't see how this is efficient or
scales. Maybe I'm missing something. For small numbers of plants maybe it can
make sense. Driving through Watsonville, Ca today on my way home from the
beach I saw hundreds of rows of crops growing with traditional drip lines.

~~~
MrTonyD
Go visit the UCSC agroecology center farm. They have been using variations of
this technique for years. I was surprised when I saw it too - I'd thought that
it would need to be more complicated.

------
mmagin
My experience:

Use valves that are suitable for low flow/pressure and work off 24 VAC so you
can use them with a cheap line-powered electronic timer.

If you need to filter or pressure regulate before the valves (probably at
least filtering), be sure to use parts rated for continuous pressure at above
typical household pressure. (100 psi ratings are probably enough)

Minimize the types of different tubing and emitters you use, it's easier to
have spares that way, so if you weed with sharp implements and cut something
it's not too annoying.

Don't go significant distances with less than the 1/2" black polyethylene
tubing.

Drip-tape is super-cheap but mostly for farm-scale row crops.

The emitters I've had the best experiences with are the Netafim Woodpecker
emitters and the take-apart-to-clean-out "flag" drippers sold by dripworks.com

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Jedd
As always, anyone trying to work with gravity fed systems that sit in the
range between ~2 metres head (the usual maximum of very low-head valves) and
standard / city pressure, are somewhat stuffed.

I'm working with about 10 metres of head - a decent standing pressure, despite
coming through 400 metres of 50mm polypipe - but it's too much for the
specialised 'water barrel' type valves mentioned here. Combined with no power
(if i had power I'd have a pump :) means it's also not feasible to use always-
closed solenoids, or have sufficient pressure to reliably get residential
grade water computer valves to open / close.

~~~
pedrocr
Have you tried something like this:

[https://www.aliexpress.com/item/Irrigation-water-
timer/15107...](https://www.aliexpress.com/item/Irrigation-water-
timer/1510781067.html)

Since it's a ball valve operated by a motor it works with zero pressure. It's
a relatively small ball valve but should be enough for almost all
applications. I have one of those controlling about 100 meters of drip tubing
from a source that's not more than 2 meters high (less if the tank is empty)
and it works fine. For better flow I'll be trying one of these ball valves:

[https://www.aliexpress.com/item/Stainless-Steel-
BSP-1-Actuat...](https://www.aliexpress.com/item/Stainless-Steel-
BSP-1-Actuator-Valve-2-Way-DN20-Electric-Motorized-Ball-Valve-
DC12V-3-Wires/32802819942.html)

It's much less convenient as they don't have an integrated controller. I'll be
trying it with this controller:

[https://www.aliexpress.com/item/NO-NC-220-240V-timer-
switch-...](https://www.aliexpress.com/item/NO-NC-220-240V-timer-switch-
multipurpose-programmable-digital-timer-module/32692258610.html)

and a 12V battery together in a waterproof casing of some sort. I've been
looking for a plastic case similar to the water timer one that's a screw on
with an o-ring but haven't found one yet.

~~~
Jedd
I actually picked up a few of the first ones there via ebay a while ago, to
trial off a smaller tank with around 2 metre head, but haven't plugged them in
yet. Winter means frosts, and no great need for automatic watering. I note
someone else has had bad experience with them - I've used the normal pressure
versions of those with some success - a couple of years, with 9-monthly
battery changes, seems reasonable for the price - just frustrating when they
go wrong (usually just before a fortnight of 40+ Celsius days).

The actuator though, that looks very relevant to my interests. I've just done
a google spiral on CR02 (and similar) wiring, to control via an arduino, say.
With 3s to close / open, and only 12V required, this seems quite feasible to
have a cheap solar charged battery sitting and running a half dozen of these
of a manifold. The benefits of a switching solenoid in terms of power
consumption, with a simpler control mechanism?

The last link you posted seems to imply it will talk to a solenoid (NC or NO)
only - would be very curious how that goes.

I have several dozen old water timers with the o-ring seal ... where the
o-ring seal has failed, and the insides rusted out. I now cover them all in
thick plastic bags, and keep them under pit covers / galv steel lean-tos.
Probably explains why they tend to last more than one Australian summer, too.

~~~
pedrocr
_> The last link you posted seems to imply it will talk to a solenoid (NC or
NO) only - would be very curious how that goes._

The way CR02 wiring works is that you have a common ground and then you feed
the 12V to one of two wires. The valve takes care of stopping the motor when
fully open and fully closed so it should minimize power consumption. So my
plan is take that normal NC/NO relay and feed the 12V to the common wire and
wire NC and NO to each of the two valve wires. Since the programmable relay
itself is also powered by 12V I get away with a single power source. My hope
is a simple pack of low self-discharge 8xAA NiMH or similar will last a
season. But a 12V lead battery and a solar panel could work as well.

Aliexpress has a very big selection of different kinds of actuated ball
valves. If they actually work reliably it seems like a great solution as it's
a normal valve operated by a motor. See this for example for a selection of
voltages and the 5 wiring types:

[https://www.aliexpress.com/item/CWX-25S-mini-electric-
actuat...](https://www.aliexpress.com/item/CWX-25S-mini-electric-actuator-
control-ball-valve-with-manual-override-function-
DN8-DN10-DN15-DN20/32812620201.html)

That one I linked was picked quite carefully to be stainless steel and CR02
wiring which seems to be the easiest to operate with just a single relay. I've
received the relay but not the valve yet so I haven't tested everything yet.

 _> I have several dozen old water timers with the o-ring seal ... where the
o-ring seal has failed, and the insides rusted out. I now cover them all in
thick plastic bags, and keep them under pit covers / galv steel lean-tos.
Probably explains why they tend to last more than one Australian summer, too._

Those are some rough conditions if the o-ring failing is enough to rust
everything. I'd expect the threading itself to provide quite a bit of
protection already. Can't imagine how you'd get much moisture through all
those threads. One thing I have noticed is that you shouldn't torque the lid
hard so as to not deform the o-ring too much.

~~~
pedrocr
UPDATE: finally got the valve and it works fine with the controller. The combo
uses 8mA when closed, ~80mA while opening (for ~5secs) and ~40mA while open
(half is the relay in the controller half is the valve). This makes it outside
the range of a simple battery but should work fine if you have a solar setup
with a 12V battery or an AC mains and a simple 12V power source. So far I'm
happy with the domestic all-in-one I linked so I'll probably not pursue this
more. If a simple NiMH pack worked I'd probably trial a full setup. But if I
was going further I'd use a DIN 12V programmable relay like this:

[https://www.aliexpress.com/item/New-DIN-Rail-Time-Relay-
Swit...](https://www.aliexpress.com/item/New-DIN-Rail-Time-Relay-Switch-
Digital-LCD-Power-Programmable-Timer-DC-12V/32785835109.html)

and a DIN 12V power source like this:

[https://www.aliexpress.com/item/DR-15-12-Hot-sales-China-
mai...](https://www.aliexpress.com/item/DR-15-12-Hot-sales-China-
mainland-15w-12v-Din-Rail-power-supply-single-output/32702839079.html)

all enclosed in an outdoor distribution box like this:

[https://www.aliexpress.com/item/Free-Shipping-
IP66-Waterproo...](https://www.aliexpress.com/item/Free-Shipping-
IP66-Waterproof-Outdoor-Distribution-Box-4-Way-Air-Swith-Box-High-voltage-
Electrical-Box/32515199355.html)

That way everything gets properly packaged using DIN elements. If you have a
12V panel/battery you don't need the AC->12V power source of course.

------
krzyk
Why not use something like a Tropf-Blumat system? It doesn't need electricity
and is self regulating. You only need a water source (it can be a barrel of
water at some height or a regular water source) - it stops feeding water when
the soil is moist enough. It uses ceramic cones to regulate the amount of
water.

~~~
andrenotgiant
This is the first I've heard about Tropf-Blumat systems, sound s pretty great
if it really works as promised.

I wonder why it isnt popular in US, price too high?

~~~
baruch
I use such a thing for a pot on the garden table but a larger drip system for
the garden itself. The Blumat doesnt require running a pipe from under the
deck onto the table and is movable but does require filling in water every few
days.

------
chabes
I've been planning an automated (raspberry pi controlled) watering system for
my garden lately. This page is a great source of information about irrigation.
It took quite a few web searches for me to find this kind of information
before I found this site. Great to see it on HN

~~~
twothamendment
I had 24 zones running with opensprinkler on a pi and loved it. About half the
zones were drip. I'm in a new place now and I'm about to put in the first
zone. I'll use the same hardware. It was stable and easy to use.

Best advise I saw in the tutorial was to make sure tubing and fitting sizes
match. It will take a few days, but they will blow apart when you aren't
looking.

------
jordanwallwork
> Drip irrigation (sometimes called trickle irrigation) works by applying
> water slowly, directly to the soil, bloop, bleep, bloop, bleep.

Such a satisfying description

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airbreather
Anyone know of some kind of in line valve for each dripper that senses
moisture and will stop flow once adequately watered?

I container garden in pots and have to over water to ensure everything gets
enough, but this causes all sorts of other problems of pooling water and
leaked water onto the balcony, leaching of nutrients.

~~~
rsync
"Anyone know of some kind of in line valve for each dripper that senses
moisture and will stop flow once adequately watered?"

There are different emitters for different rates ... I have 1gph as well as
.5gph emitters for various purposes and I think there are other choices as
well.

I would think you could run the water the same duration for all of them, but
vary their irrigation with different rate emitters.

I recommend graduating from the hardware store tooling to the professional
Netafim hoses/emitters/couplings.

------
GrumpyNl
This is how my grandmothers does it. Put a glass / bucket of water next to the
plants, take a string of wool, hang it in the bucket and push the other end in
the soil. Perfect moist for the plants all the time.

~~~
agumonkey
how high is the water in the glass ? capillary traction can pull water a lot ?

------
yugoja
I'm pretty skeptical about drip's performance compared to flood method when it
comes to resource intense crops like sugarcane.

Is anybody qualified enough on this topic here to counter me on this?

------
shostack
I want to landscape my yard and switch from sprayers to drip. I have an old
system, and honestly am completely overwhelmed by setting up irrigation.

Am I overcomplicating things? Or is it really that hard to get it set up
properly with correct pressure such that I'd be better off just hiring someone
to install it?

~~~
mmmBacon
Slow down, take a deep breath it's not hard! It should not be hard
particularly if you are on a city water supply. If the system is old you'll
want to check that there are appropriate backflow preventors on the system and
that they are installed correctly and that they work . Once you have that you
install an inline pressure regulator to get the pressure down and simple
inline filter on the line at the manifold where your valves are. This helps
keep the drip lines from clogging. If you have pop up sprinkler heads you can
easily retrofit them with drip. If you have the old style fixed spray heads
you can still retrofit them to drip but it may be more work if you want to
hide the drip lines. The whole conversion is very easy because your main lines
have already been trenched. Trust me I've trenched my own lines and this was
hard tiring work even with a trenching machine.

Some good info here: [http://www.urbanfarmerstore.com/converting-sprinkler-to-
drip...](http://www.urbanfarmerstore.com/converting-sprinkler-to-drip-at-the-
spray-head/)

~~~
shostack
Thanks for the info. TBH, it seems like describing the process at a high-level
is very easy, but each of those steps you listed probably has some education
that is needed to set them up properly, know what to look for, research into
brands, etc.

Or am I overthinking that part of it?

------
WalterBright
For spot drip irrigation, I take an empty gallon jug, poke a hole in the
bottom with a tack, fill with water, and set it next to the plant.

------
bfu
Zero mentioning of limescale

