KPUD Home | Contact | Employment | Sitemap

Using Micro-irrigation

- by Ron Hall, Turf Magazine

Micro-irrigation is one of the most valuable water-conserving techniques for keeping flower beds, trees and hard-to-irrigate areas of a landscape healthy and attractive. Just about any landscape with small, oddly shaped areas, young trees or flower beds would benefit from micro-irrigation.

What exactly is micro-irrigation and, in particular, micro-sprays? Do you currently install them? Installing micro-sprays is a relatively simple task, which we'll discuss later. Let's get back to the definitions.

Thomas F. Scherer, an agricultural engineer from North Dakota State University, defines micro-irrigation as low-pressure irrigation systems that spray, mist, sprinkle or drip. They dispense water via emitters with rates measured in gallons per hour (GPH), rather than gallons per minute (GPM) like most systems to irrigate turfgrass. Micro-irrigation systems may be arranged in a variety of branched layouts to provide water as close as possible to plant roots or to the base of plants. Variations of these systems have been used throughout history for agriculture, but more recently in plant nurseries and greenhouses. The use of micro-irrigation in the landscape industry is increasing, as systems are designed to apply precise irrigation to areas of a landscape with differing plant types (hydrozones).

Micro-sprays or micro-sprinklers - the name varies depending upon specific function and manufacturer - comprise one category of micro-irrigation. In most cases, micro-spray is delivered through poly tubing to nozzles attached to risers, either pop-up or fixed. Bubblers are especially effective for irrigating ornamentals in containers. Drip irrigation is another category of micro-irrigation. Drip systems release small amounts of water via emitters to plant roots belowground (subsurface drip) or to the base of plants aboveground. Just about all methods of micro-irrigation operate with pressures between 15 and 30 PSI. Low-volume systems have a low precipitation rate, so typical system run times are much longer than high-pressure systems.

From the above description, it's apparent that micro-spray is a cross between surface spray irrigation and drip irrigation. One of the advantages of micro-sprays is that they can easily be configured to connect to PVC pipe, risers, poly tubing, distribution tubing and both high and low-pressure pop-ups. They're especially suited for any area where there are many low-profile plants close together, such as beds of annuals, small areas of ground covers, and in some instances trees, including street trees or specimen trees, and especially those that have been newly planted.


Micro-Sprays at a Glance

Uses

  • Large groupings of plants with similar water needs
  • Misting of new bedding plants

Advantages

  • Emitters available in a large variety of spray patterns
  • Easily moved to new locations
  • Emitters can be simply exchanged or removed
  • Emitter lines can be easily repositioned
  • Easy to tell if emitter is clogged
  • Can be used for all soil types
  • Fertilizers can be applied with water through the system to reduce labor requirements

Disadvantages

  • Many parts can be easily damaged
  • Visibility can lead to vandalism
  • Generally have greater maintenance requirements
  • Water is sprayed into the air, where it is subject to wind drift and evaporation
  • Animal, and especially rodents, may cause damage to components
  • If emitters are poorly placed (too far apart or two few in number), root development may be hampered
  • Drip tubing can be a tripping hazard especially for children (cover with mulch and fashion with anchor pins every 2 to 3 feet)
  • Drip lines can be cut while doing landscape maintenance


Installing Micro-Irrigation

Design is the first step in installing any irrigation system. In the case of micro-sprays, keep it simple. Make a sketch of the areas you would like to water; consider using graph paper. Take into account plant types, location of trees, shrubs, ground covers and bedding plants. Don't overlook plant density and plant water needs. This will give you a reasonably accurate assessment of the type and number of micro-sprays you will need. Also, keep in mind plant growth. Will the plants grow so large that they will block irrigation before the season is over? Also, take into account sidewalks and other areas with hardscapes when selecting micro-irrigation products.

Installing micro-spray emitters is relatively simple. All landscape irrigators should know where and how to install them. Technical and practical information can be found on irrigation product manufacturers' websites. A little searching on the Internet turns up several short and practical videos on micro-sprays as well. They're well worth the few minutes they take for a refresher on the subject.

For example, Sean Stefan at Sprinkler Daddy (www.sprinklerdaddy.ca) has posted a seven-minute YouTube video that walks viewers through the installation and use of micro-sprays using 6-inch, 12-inch extension, staked and pop-up risers. He provides tips on where to use each, including how to attach the risers to the .75-inch supply line. He also shows the different types of micro-sprays - quarter, half and full-circle sprayers - and how easy it is to punch them into the .25-inch "spaghetti" tubing.

View the video by typing "Sprinkler Daddy micro-spray" into your browser search function. Visit websites of irrigation manufacturers for detailed product specifications. Several also offer similar and more detailed videos explaining micro-sprays.

Generally, it's not recommended that the system include various heads within the same zone, since different emitting devices often require different run times for efficient water application.

A well-designed and installed low-volume micro-sprinkler system can be just as durable and easy to maintain as a conventional sprinkler system, and if the system is monitored on a regular basis, both water savings and improved plant growth can be achieved, according to Stuart Spaulding, CLIA, technical service manager at DIG Corp.

Ron Hall, editor-in-chief of Turf magazine, has been reporting on the green industry for the past 28 years. Contact him at rhall@mooserivermedia.com.

Education

Events

  Events List

Learning Center

  Drinking Water

  Kids

  FAQs

  Free Private Well Class

   The Groundwater Story

Presentations

  Program List

Water Conservation

  WUE Rule

  Commercial

  Residential:
Indoor

find us on facebook