Poly Tubing, Drip Tape, Drip Line, and Soaker Hoses
In the world of drip irrigation there are many methods to deliver water to thirsty plants. These methods are referred to by many different terms, often used interchangeably. The purpose of this article is to elucidate the differences between these common methods. Drip tape, drip line, tubing and soaker hoses are all terms you have likely run across in your drip irrigation research, but these terms are often used without proper explanation.
Poly tubing is the most common way to deliver water to an irrigation area. Unlike the other methods considered in this article, tubing itself does not emit water, however emitters (also called drippers) can be punched into the tubing in places water is needed. We offer poly tubing in various sizes, from ⅛” to 1”. The ⅛” and ¼” sizes of poly tubing are most often used in short lengths with an emitter installed at the end of that length to deliver water to 1 or more plants. The larger sizes (½” to 1”) are most often used as mainlines to deliver water to the smaller sizes of poly tubing, drip line and drip tape.
As noted previously, the larger sizes of poly tubing can be punched and emitters installed anywhere along their lengths. For example, if you had a 100’ row of tomato plants planted at uneven intervals, you could run 100’ of ½” poly tubing along the row and place an emitter in the tubing wherever a plant required water.
To learn more about poly tubing, its limits and uses, please see our Tubing Buying Guide.
Drip tape is often confused with soaker hose and drip line, however it is actually a very different product that is free of some of the limitations that apply to drip line and soaker hoses. That’s not to say Drip Tape has no length limits, however it is not as limited as poly tubing and drip line. When long lengths are required, such as in farming or long residential applications, drip tape is often the go to solution. Drip tape is often used in low pressure applications, working optimally at 8-15 PSI.
While drip tape can be used in longer lengths than poly tubing and drip line, it is not entirely without limit. How long you can make a drip tape line will depend on many factors, including: size of the drip tape, inlet pressure, elevational changes and flow rate. These factors all affect the emission uniformity rate of the system. Calculating emission uniformity is a bit of an involved process, but probably not something the average residential irrigator will need to consider unless their project is larger than usual. A commercial irrigator will likely possess a deeper understanding of the formulas involved.
For most consumers the biggest limitation to consider is flow rate. Long runs of drip tape can quickly overtax your incoming flow rate. For example, if you have 10 100’ runs of drip tape with 1 GPH emitters spaced every 24”, you’ll have a total flow demand of 500 GPH; this level of demand could be difficult for many residential faucets to supply.
The last limitation to consider is in design. When drip tape is filled and pressurized it is not flexible and thus can only be used in straight lines.
To learn more about drip tape, please see our Drip Tape Buying Guide.
Drip line is most often confused with soaker hose, however as you will see they are very different products. Drip line is similar to drip tape in that it has emitters of various emission rates installed at evenly spaced intervals, however the similarities stop there. Unlike drip tape, drip line is limited in length to the same limits of poly tubing of corresponding size. This means that ¼” drip line should never be longer than 30’ in a single run and ½” drip line should never be longer than 200’ in a single run.
Drip line does have one advantage over drip tape in regards to flexibility. ¼” drip line is reasonably flexible, in fact it is often used to make rings around trees in order to water the entire root system of a tree evenly. ½” drip line isn’t quite as flexible as ¼” drip line. It is as flexible as poly tubing, meaning it can take gentle turns and bends but not sharp corners or 90 degree angles without the use of a fitting. Drip line uses the same fittings as poly tubing of the same size, this means that our Perma-Loc Fittings can be used with our ½” drip line and our Barbed 1/4" Fittings can be used with our ¼” drip line.
To learn more about drip line, please see our Tubing Buying Guide.
Soaker hoses are a relatively modern invention, and while drip line and drip tape are often referred to as soaker hoses they are actually a product unique unto themselves. In fact, soaker hoses are not compatible with drip irrigation or pressurized systems. Soaker hoses are most often made of rubber and other recycled material that is perforated throughout its length to allow water to seep out. In this regard it is similar to drip irrigation products, however there are some disadvantages inherent in its design.
Because soaker hoses seep water along the entire length, there is no fine tuned control to where the water is delivered. If your plants are spaced 6” apart, there is little sense in watering the dirt (or even worse, the weeds!) between them. Soaker hoses are also notorious for weeping more water out of the part of the hose closest to the water source than the ends furthest away. This is because soaker hoses do not (generally speaking) operate as part of a pressurized system. Even if water conservation isn’t a concern, the higher water bill from wasted water certainly is.
One advantage to soaker hose can be when a long hedge of bushes requires watering. Soaker hose is good at this aspect as it can be laid along the entire length of a hedge and the perforated design means every portion of the hedge will receive water. However the concern of uneven water distribution cannot be ameliorated and parts of the hedge may receive too much water while others may receive too little; this becomes even more noticeable on uneven terrain. Soaker hoses, at the end of the day, are among the most primitive form of drip irrigation and other methods would likely see greater success and less waste, but there are situations (such as long hedges) where it can be advantageous.