Drip Irrigation Tubing – What's the Difference?

The drip irrigation industry does not currently maintain standards concerning the various sizes of irrigation tubing. When you hear tubing referred to as 1/2", 3/4", 5/8" etc., these designations are just generalities. For example, many manufacturers produce 1/2”  tubing (also referred to as "poly tubing" because it is made from polyethylene), but the outside diameters (OD) and inside diameters (ID) can be quite different. In fact, 1/2" poly tubing can refer to at least 3 different tubing sizes. 

This lack of standard sizes often results in incompatibility with tubing and fittings between manufacturers. If you purchase all of your tubing and fittings from the same manufacturer, you can be certain that they will all be compatible. However, If you have an existing drip system and you want to add to it, you'll need to ensure that you get the proper sized tubing and fittings, or get the correct reducing couplings to mate the systems. In contrast, smaller diameter 1/4" tubing also comes in different sizes, but even different sizes of 1/4" tubing will usually work together.

 

To match your fittings to your tubing, you'll first need to obtain the OD and ID of the tubing. The OD and ID is usually listed in thousandths of an inch. For tubing with an OD of .700 and ID of .600, that translates to an outside diameter of 700/1000 of an inch and an inside diameter of 600/1000 of an inch. The thickness of the tubing can be calculated as the difference between the OD and ID, or 100/1000 of an inch in this example. Some suppliers also offer universal fittings to match a range of OD or ID dimensions to make it somewhat easier to mate unmatched tubing.

“Drip Line” differs from standard poly tubing as it has emitters embedded within the tubing at specific distances apart, such as every 12”. “Drip Tape” is generally the same as drip line, but it differs in the wall thickness and lays flat on the ground when not in use. Drip tape thickness is commonly listed by the manufacturers in metric units, and is usually available in thicknesses of 8, 10 or 15 mils (millimeters). Drip tape must be laid out in straight lines, while drip line can be curved somewhat. For sharper turns, elbow fittings should be used with drip line or standard poly tubing to avoid kinks in the line which can decrease or even cut off the water supply. Kinks in the tubing are common when it is coiled, bound and shipped.  Kinks rarely result in leaks, and the tubing will usually revert to a naturally rounded shape once it is laid out, allowed to warm up, and the system is pressurized with normal use.

Vinyl irrigation tubing, most often found in micro tubing only, is made from flexible polyvinyl chloride (PVC) and performs the exact same function as polyethylene or “poly” tubing.  The inside and outside diameters of the vinyl and poly micro tubing vary only slightly.  The primary difference between the two are that vinyl tubing tends to be more flexible than poly tubing. This can be either good or bad depending on your needs. Vinyl tubing can make tighter turns without kinking, but vinyl tubing tends to have a slightly shorter lifespan than its poly counterpart. Poly tubing is made from a more stable polymer than vinyl tubing, and as such, is less likely to break down and enter the water stream. In the end, you should use whatever tubing material you feel comfortable with.  

Different tubing sizes have different capacities in regards to maximum single run lengths and maximum flow rates.  For ¼” tubing, the maximum single run length is 30 feet, and the maximum flow rate is 30 gallons per hour (gph).  This relationship is sometimes referred to as the “30/30 rule”.  For ½” tubing, the maximum single run length is 200 feet, and the maximum flow rate is 200 gph (the “200/200 rule”).  For 3/4” tubing, the maximum single run length is 480 feet, and the maximum flow rate is 480 gph (the “480/480 rule”).

For example, if the distance between your water supply and the end of your planting area is over 30 feet, you would not be able to use the 1/4” tubing for that run, since you will have exceeded its maximum single run length limitation.  As another example, if you are using 32 gph micro sprinklers with 1/2” mainline tubing, you can only use a maximum of 6 of these sprinklers to stay within the tubing capacity (32 x 6 = 192 gph required).  Exceeding the tubing capacity in either run length or flow rate may result in inconsistent water flow at your emitters within your drip irrigation system.  

Drip Irrigation poly tubing, drip line and drip tape can be buried underground and/or covered by mulch. Keep in mind though that burrowing rodents like gophers can chew through the tubing. If you decide to bury your tubing, make sure to monitor your system regularly so any problems can be identified and corrected in a timely manner.

Whether the difference is size, material or type, the differences in drip irrigation tubing can sometimes be confusing. These differences, however, also allow more flexibility in obtaining just the right components for all your varied watering needs. Happy gardening!

 

Introducing the ECO1 Ambient Light (Solar) Powered Irrigation Timer

Drip Depot is proud to offer the world’s first sustainable low maintenance, easy-to-install irrigation timer that does not use electrical wires or batteries. It’s patented ambient light technology is so advanced that it doesn’t need direct sunlight.  In fact, it can generate enough power from moonlight as well as dim, ambient light to stay charged and continue working both day and night in any weather condition.  In addition, the ECO1 Timer http://www.dripdepot.com/1747 employs SimpleSmart™ technology which automatically adjusts irrigation schedules as seasons change to help eliminate over and under watering, ensuring a healthy landscape while saving you time, money and water.

In addition we offer the timer model (ECO1 MVA) http://www.dripdepot.com/1748 that includes a manual valve actuator, which replaces an existing manual valve stem in a brass anti-siphon valve to make it automatic. A hose end timer model will be available soon, allowing the timer to connect to any standard hose bib or garden hose.

Uses Renewable Energy:

No batteries to change or replace

No wires

No direct sunlight required

Features:

Up to 5 start times per day with run times from 1 minute to 6 hours

Instant manual watering with a touch of a button

Suspend and Rain Delay functions with automatic restart

Set seasonal, monthly and daily irrigation restrictions

12 month budgeting from 0 to 200%

Benefits:

Saves water

Rain Sensor compatible for improved water savings (rain sensor not included)

SimpleSmart™ technology uses regional climate programming to automatically adjust for seasonal changes

The ECO1 Timer is manufactured by the DIG Corporation, founded in 1981, which provides a comprehensive line of quality low volume irrigation products. The ECO1 Timer is the latest in their line of controllers powered by ambient light, which is much more sensitive than solar powered controllers.

We love getting feedback, so please feel free to share your experiences on this topic, whether or not you found this article helpful, and if there are any specific topics you would like us to cover in the future.

The History of Drip Irrigation

Drip irrigation is quickly becoming the standard irrigation method for many applications such as home gardens and landscapes, greenhouses, vineyards,  row crops and orchards. The technology and materials have seen some significant changes throughout the years, but the basic concepts have generally remained constant.

Innovative irrigation methods, other than just getting water onto the ground, have been practiced since ancient times. One early method involved burying clay pots filled with water within a planting area, allowing the water to gradually seep into the soil at the plant's root zone. The era of drip irrigation began in 1866 in Afghanistan, when researchers began utilizing clay pipe to both irrigate and drain planting areas.

In the 1920's, growers in Germany began using perforated pipe to irrigate plants. Once plastics were developed and widely used after WWII, an Australian inventor named Hannis Thill began to use a specific plastic pipe configuration with long passageways to evenly distribute water to crops.

In 1959, Simcha Blass and Kibbutz Hatzerim developed and patented the first practical surface drip irrigation emitter. The emitter concept was developed several years earlier by Simcha and his son Yeshayahu in Israel. Instead of releasing water through tiny holes easily blocked by tiny particles, water was released through larger and longer passageways which decreased the water velocity as it exited the piping.

Drip irrigation options have also expanded to include compatible devices such as micro-sprayers, bubblers and misters, which deliver water in a different manner than drip emitters. These emitters with a wider water dispersion are generally used on plants and ground cover with wider root zones.  Subsurface drip irrigation (SDI) uses permanently or temporarily buried dripline or drip tape located at or below the plant roots. This type of drip irrigation tubing has emitters embedded within the tubing spaced evenly apart. It is becoming popular for row crop irrigation, especially in areas where water supplies are limited or recycled water is used for irrigation.  Careful study of all the relevant factors like land topography, type of soil, water supply characteristics, crop and climate conditions is needed to determine the most suitable drip irrigation system and components to be used in a specific installation.

Modern drip irrigation has arguably become the world's most valued innovation in agriculture since the invention of the impact sprinkler in the 1930s, which offered the first practical alternative to surface irrigation.  Crops are now growing in desert climates which would not have been feasible without drip irrigation.  Water conservation efforts in some regions of the world susceptible to drought have incorporated drip irrigation as the primary method of watering crops.  Crop yields in virtually all environments have significantly increased while utilizing less water due to drip irrigation technology.

Dr. Daniel Hillel, a research scientist at Columbia University's Earth Institute, was recently named the 2012 recipient of the World Food Prize honoring "individuals who have advanced human development by improving the quality, quantity or availability of food in the world."  He has worked in Turkey, Pakistan, Sudan and other Middle Eastern countries to spread drip irrigation technology to all who could benefit from it.  Described as the "Father of Sustainable Water Management", he promoted agricultural development which does not rely on industry for fuel, pesticides to control pests and chemicals to increase soil fertility.

Drip irrigation is still evolving, and advancements are still being made in materials and techniques.  Growers are increasingly becoming aware of how precious water is as a resource, how it’s efficient usage and management can assist agriculture, and how drip irrigation technology can positively affect society as a whole.  Drip irrigation has truly become, and will continue to be, a benefit to us all.

We love getting feedback, so please feel free to share your experiences on this topic, whether or not you found this article helpful, and if there are any specific topics you would like us to cover in the future.

Know Your Soil Types

When putting together your drip irrigation system, it is useful to know what type of soil you have in your planting area. You do not need to be a soil expert, but you should be aware that water moves differently and creates different wetting patterns through the different types of soil: sand, loam and clay. The term “wetting pattern” refers to the way that water is distributed below the surface of the soil both vertically, through the force of gravity, and horizontally, through the capillary properties within the soil.

Sandy soil – Water moves quickly through sandy soil and does not travel far from the dripper. The wetting pattern is much more vertical than horizontal in this type of soil. If your soil is sandy, then you may want to use higher flow drippers and drippers that are spaced closer together to ensure your plants receive enough water. With a higher flow, you may also want to water for shorter durations, but more often.

Loamy soil – Loamy soil is more dense that sandy soil so water will travel slower allowing it to spread more evenly through the soil both vertically and horizontally. Mid-range drip emitters may be a good choice and you can space drippers further apart since the wetting pattern will be larger.

Clay soil – This type of soil is very dense, which causes water to be absorbed very slowly. Drippers with the slowest flow rate are a good choice to prevent the water from pooling on the surface of the soil near the plant. Any water at the surface of the soil could eventually be lost to evaporation or runoff to areas you don't wish to water. With lower flow rate drippers, you should water for longer durations to ensure your plants receive enough water.

For any soil type, you should only see a small wet spot of about 3 to 4 inches in diameter on the ground below a dripper. All the action is really happening below the surface. To determine the actual wetting pattern for your specific soil, run your drip system for about 30 minutes, let sit for 30 minutes and then dig into the soil below a dripper to see how far the water has traveled vertically and horizontally. You'll be able to see exactly how the water is dispersing at the root zones of your plants, and you can adjust your system setup accordingly if necessary.

A simple method to determine your soil type is to grab a handful of dry soil from the area or areas you wish to drip irrigate. Make a fist while holding the dry soil in your hand, then open your fist. If you have sandy soil, the soil in your hand will crumble without hesitation. If the soil holds together but slowly falls apart, then you have loamy soil. Lastly, if the soil holds its shape, then you have clay soil. This method is not scientific, but works well for most people. If you need a more detailed analysis, there are agencies that can test your soil for you.

By knowing your soil type and how water behaves under the surface, you'll be able to design your drip irrigation system with the right components and the right watering schedule to ensure your plants stay healthy. Happy gardening!

We love getting feedback, so please feel free to share your experiences on this topic, whether or not you found this article helpful, and if there are any specific topics you would like us to cover in the future.

Zoning your Drip Irrigation System

Many smaller residential drip irrigation systems do not require “zoning”, or dividing the system into two or more areas. Some medium and larger systems, however, would benefit by zoning in order to increase the system's overall efficiency, minimize water waste, and improve the health of the plants.

Zoning might be desired if you have plants with very different watering requirements. For example, you might want flowering plants, shrubs, and trees all on separate zones as the amount and the frequency of watering is quite different for each type of plant. If all of these types of plants were on the same zone, some plants would invariably be over-watered while some would be under-watered.

Zoning might be required if the number of plants and their cumulative watering needs would exceed the capacity of the water supply or irrigation tubing. For example, a water supply with a flow rate of 300 gallons per hour (gph) would not be able to sustain a single planting area requiring 400 gph, but it would be able to sustain two separate planting areas requiring 200 gph each if the two separate zones were watered at different times. Another example would be if a single planting area with ½” tubing required a flow rate of 400 gph. That would exceed the maximum capacity of 200 gph for 1/2” tubing, so splitting into two zones would be necessary. With all the math floating around the process can seem very overwhelming but we have created a lot of reference material in our online classroom to help you.  In addition our knowledgeable staff is always here to help you through any of your zoning questions. We can be reached at  support@dripdepot.com.

Zoning can be accomplished by several methods. One common configuration is to use a faucet splitter and create two zones and a more complex option involves PVC piping, with the water supply pipe connected to a manifold consisting of two or more electronic valves which then direct the water to different planting areas. Modular multi-zone manifolds are also available which can be adapted to connect to standard hose bibs and standard irrigation tubing. Some battery-operated water timers are designed for two zone operation. These timers can be connected to a single hose bib, and have two separate water outlets with separate timer options. An innovative product which has recently become available consists of a compact valve box which allows a single water inlet connection and four zone outlets controlled by separate compact electronic valves.

If your planting area consists of plants with different watering needs and zoning is not an option for any reason, you can still vary the amounts of water each plant gets by varying the number and types of emitters at each plant. Adjustable flow rate drippers can give you that variability, but it is sometimes quite difficult to balance the output on adjustable drippers if you have more than one adjustable dripper on the zone. You can also vary the drippers in your planting area by the dripper's individual flow rating. For example, if you have two plants and the second plant needs twice as much water as the first, you can install a 1 gallon per hour (gph) dripper on the first plant, and a 2 gph dripper on the second. If you only have drippers with the same flow rating, you can install twice as may drippers on the plant that needs twice as much water.

Being able to zone your planting area and vary the drippers and/or drip rates at individual plants will give you the ability to very precisely control the water usage. You'll be able to give all your plants just the right amounts of water. An efficient, correctly-zoned and well-balanced drip irrigation system will inevitably result in less water waste, more cost savings and healthier plants.

Do-It-Yourself Tips for Drip Irrigation

As drip irrigation systems become more user-friendly, more individuals are successfully designing and installing systems themselves and saving the expense of hiring irrigation professionals to accomplish these tasks. Most systems, in fact, can be installed quickly with no tools necessary other than a standard household pair of scissors. We’ve compiled some tips from installation professionals provided especially for those “weekend warriors” to help with the  DIY installation process of a standard drip irrigation system.

Hot Water for Tubing:
 A trick among drip irrigation professionals is to briefly insert the end of a piece of tubing into a cup of hot water before attempting to connect fittings to the tubing. As a side note, lubricants should never be used on drip irrigation tubing.

Place Tubing in the Sun:
 Many drip irrigation installation experts place their roll of tubing in the sun prior to installation, which allows the tubing to “warm up” and become more flexible.

Punching Holes in ½” or Larger Tubing: 
 A little known but valuable tip is to punch holes in your poly tubing when it is cold, like in the morning before the sun warms the tubing too much. Punching holes in tubing when it is warm can be a challenge and frustrating.

Know your Soil Type:
 Most drip irrigation installation experts agree that before installing any drip irrigation system a person should identify what type of soil they have. Soil type greatly influences how water penetrates and travels to your plants' roots. There are 3 soil types: Clay, Loam and Sand. Clay soils are tightly packed and water does not penetrate quickly into the soil. Drip emitters with slower drip rates, like .5 gallons per hour (gph), are ideal for this soil type to prevent water from accumulating on the surface. Sandy soil experiences the quickest water penetration rate, so a drip emitter with a faster flow rate, like 2 gph, would be recommended.  Loamy soil falls in between these two in regards to water penetration rate, so a drip rate of 1 gph would work well.

Cutting Tubing:
 Don't be fooled into buying a special tool to cut poly tubing, which can easily be cut using household scissors. 

Don't Over Tighten:
 Many drip irrigation installation professionals note that a common mistake made by first time drip irrigation installers is to over tighten pressure regulators, backflow preventers and other faucet assembly parts. Over tightening these products can actually damage the products and cause them to leak. All parts in a drip irrigation system should only be hand tightened, and teflon tape or glues should not be used.  Keep in mind that  two different thread types are commonly used with drip irrigation systems.  Hose threads are sometimes referred to as MHT for male hose threads and FHT for female hose threads.  Pipe threads also can be designated as MPT or FPT.  Hose threads and pipe threads are not compatible, but adapters are available to make connections between the two when necessary.

Control Your Water:
 A great way to manage the water flow in your drip system is by using shut off valves for the specific size of tubing you are installing. Drip irrigation professionals use shut off valves in two ways. First, the valve can be installed inline which allows water flow to be adjusted based on your watering needs. Secondly, the 1/4" valves can be used as a drip emitter. This allows the amount of water to an individual plant to be adjusted or shut of completely depending on your watering needs.

Fixing Holes in your System:
Holes in tubing happen. Fortunately, a tubing coupler can repair holes in poly tubing without having to replace the whole system. Experts simply cut out the damaged part of the poly tubing and then reconnect the two “fresh” ends with the coupler.

Reuse your Fittings: 
Some reusable tubing fitting brands (like Perma Loc) have become popular among drip irrigation professionals. These fittings are unique in that they can be reused an unlimited number of times as opposed to compression or barbed fittings which can only be used once. Drip systems can change from year to year and reusable fittings allow you the flexibility to do so easily and economically.

Insert Goof Plugs Easily:
 A well kept secret among drip irrigation installation professionals is how to install goof plugs easily. Anyone that has tried to insert a small goof plug into ¼” micro tubing will appreciate this tip. Try using a pair of needle nose pliers to grip the opposite end of the goof plug that you wish to insert into the micro tubing. The added leverage of the pliers will make this task a breeze.

Install a Timer:
 Drip Irrigation experts recognize that in order to reap the maximum benefits from a drip irrigation system a timer is a must. Timers allow water schedules to be set and carried out without worry day after day. Although drip systems are efficient without a timer, an addition of a timer will save you more time and more money.

Clean Your Filter: 
Drip irrigation professionals note that regularly cleaning the filter in a drip system can help keep your system running at full efficiency. A filters is an important component of any drip system, and keeps debris out of your system that could clog the small openings on most drip emitters.

Winterizing your System:
 Winterizing a drip irrigation system is easy. Timers and head assembly components (backflow preventers, filters, pressure regulators) need to be removed and stored indoors. Most drip irrigation parts are made of extremely durable plastic which can withstand freezing temperatures as long as the water is removed from the system. Drip irrigation experts commonly install a threaded end cap at a low point in the system which allows the water to be drained out of the system easily. Once the water is drained out, they simply screw the cap back on and it's ready for the winter.

Meet the Staff - Aaron

We will occasionally feature a member of the Drip Depot staff in our blogs to let our customers get to know a bit about the people working hard to provide the best products and service to them. 

  
Aaron works in the Drip Depot warehouse in White City, Oregon, and is responsible for such tasks as packaging and shipping orders. He was born and raised in southern Oregon, and is a football fan of both the University of Oregon Ducks and the Oregon State University Beavers. That's quite a juggling act since most Ducks and Beavers fans prefer that everyone choose a side, especially when the two rival teams play each other in the annual “Civil War” football game. You can often find Aaron outdoors on the weekends, mainly camping or dirt bike riding, or both. Aaron enjoys wake boarding in the summer, and his favorite type of food currently is Indian. Ask him again, he says, and he will probably give a different answer each time. One of his favorite places he's visited recently is Multnomah Falls near Portland, Oregon. The falls features a beautiful arch pedestrian bridge, and is the second highest year-round falls in the U.S. Aaron likes the often fast paced work environment in the warehouse, and really enjoys the variety of tasks he performs. He is proud that the company offers the best drip irrigation products available.