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Many years ago, I came across a short item
in Sunset Magazine (August 1991) that described using a bucket to feed a drip
irrigation system. This had a great deal of appeal to me, as I did
not want to mess with the complications of hooking up a drip system to a
water supply.
My recent Google search for "bucket drip" or "gravity drip" revealed
that this system is in widespread use in the developing world.
The bane of drip irrigation is clogging of the drippers, and to a lesser
extent, the lines, so some sort of filtration is needed.
The basic system is very simple: drill a
3/16" hole as close to the bottom on the side of a 5 gallon paint bucket or other
container as you can. Insert 1/4" drip tubing (use a small screwdriver, and
this will take some force). No additional sealant is required if the fit
is tight.
Inside the bucket, place an adaptor
(which serves as a filter: see below). Hint: it is much easier to
attach the filter to the line and then insert the line into the hole in
the bucket from inside the bucket, rather than trying to put the filter
on the line after it is inserted in the bucket. Place the bucket on something to elevate it, and
turn the the bucket so that the tube is at the lowest point.
I prefer to use the more supple 1/4" vinyl (rather than polyethylene) tubing, as it is
easier to work with. The 1/4" size is often
referred to as "micro tubing". |
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If your bucket is too transparent (some
food supply buckets are) the light will encourage the growth of algae.
Whatever you use to elevate the bucket needs to be sturdy, as water is
heavy (5 gals is about 33 lbs.). Try to place the bucket on the highest
ground. I would use a larger container (such as a small heavy duty
garbage can), but I don't have a way of elevating it. |
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For the filter, I use DIG corporation part number 21 (also known as
C37B).
It
comes with a conical screen filter washer, into which I insert a very small
quantity of
aquarium filter floss (about 3/4 of a teaspoon; don't pack
it tight). You can get part 21 at some
Home
Depot retail stores (as of August 2007). You can also use
polyester batting (available from fabric
stores; the stuff seems identical to aquarium floss) instead of filter floss.
An
alternative part is Raindrip Swivel Connecter A325C (3/4" Hose
Thread Swivel x 1/4" Compression Adaptor), which are available at
Amazon.com and
Lowes retail stores for about $1.50
(as of August 2007). Also, Mister Landscaper makes
a part that
actually looks easier to use, since inserting tubing into the adaptor is
not easy.
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Other alternatives are to make filters
out of found materials. Drill a hole in a bottle cap or a drinking
cup, inset tubing, seal the seams with silicone seal or
Amazing Goop, and fill
loosely with filter floss. A section of window screen cut to fit just
inside the bottle cap or cup will keep the floss from coming out. |
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Bucket lid details: Attach a piece of scrap wood
(such as a piece of a old broom handle, or any small block, as shown,
using a wood screw) to serve as a handle for the lid. Be sure to
drill a small air hole in the lid to allow air into the bucket -
otherwise the water will not run out the tube. Without a lid, debris
will fall into your bucket and create clogs. Also, since you will have a
small amount of standing water in the bucket, you want to keep
mosquitoes out. |
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Inline
drippers have two barbed prongs (left). Terminal drippers (right)
have one.
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Inline drippers.
I prefer to use
Raindrip mini inline
drippers so that I can string them all in a line. If you use terminal
end drippers, you end up with too many divergent lines. The disadvantage
to a long line of inline drippers is that a clog in the tubing denies water to all of the drippers downstream.
I end the line with a terminal dripper.
I
like to keep the drippers elevated off of the soil (with
stakes) so that
I can see the drops as a visual check.
You will need to purchase a supply of barbed
connectors to join parts of the line together, as your lines become a
patchwork of different lengths spliced together. |
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I use pliers coated with
electrical tape to put (and remove) the brass adaptor on the
faucet: the sharp threads are not friendly to bare hands. |
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Dripper testing and unclogging.
I throw all suspect drippers into a jar and soak them in a vinegar
solution, with some jar shaking.
To
test them, I hook up one of the filter adaptors (see above) to a faucet,
using Python part
number 69HD brass faucet adaptor. You can get this part from
pet/aquarium stores or online, and I suspect that a similar adaptor is available
from hardware stores. Python does make a plastic version of this
adaptor, but I found it very difficult to use. |
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You may have
to rig up a different adapter setup if your faucet has different
threads. I add a short length of
tubing; I then connect up a dripper and turn on the faucet (just a
little pressure is needed). With inline drippers, you have to cover the
end with your finger to force the water out of the dripper hole. If it
doesn't drip, I try to clean out the hole with a dissecting needle. If
that doesn't clean it out, I put it aside in anticipation of the day
that I discover a better method of unclogging. |
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:
Tools: the right tools will make
work a lot easier |
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Light duty
pruning shears: Tubing is harder to cut than it looks; you
can use scissors or wire cutters, but good pruning shears do it
effortlessly and make for a cleaner cut. |
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Pliers: use
two pairs of inexpensive pliers to pull tubing apart from drippers
or connectors; it can take quite a bit of force to get them apart,
especially in cold weather. |
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Locking
Forceps: (also called hemostats) inexpensive non surgical versions
are used by fishermen to help unhook fish. I use these to
close off the flow of water when working on replacing drippers and
tubing sections.
Jann's Netcraft
has inexpensive versions.
Vise Grip Pliers might also be used instead of hemostats.
I imagine a
C-Clamp (which could be a lot cheaper) would also work. |
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Dissecting
Needle: instead of a safety pin for unclogging and piercing, I
prefer to use a
dissecting needle, basically a pin with a handle.
You can often get these at college campus bookstores or on the web.
For safe storage, stick the needle into a cork. |
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