I suppose somewhere, somehow there exists a perfect irrigation system. That is, an accretion of a water delivery complex that is completely durable, precisely distributive—excellently calibrated to avoid overwatering, under watering, run-off and erosion—is ideally suited in all locales to sun, shade, soil type, evaporation rates and temperatures; is easy to adjust, maintain and repair; is precisely balanced as to both water supply and water quality; is adaptive to the changing seasons; and as well, is simple to manage and is reasonably priced.

Well, there is not. Indeed as may be seen, a one sentence description of irrigation variables reveals a lot of issues that are brought to bear when we consider the overlapping complexities which should properly be considered when the need to develop a watering system arises. From a practical viewpoint, I find it helpful to acknowledge these complexities and accept a certain amount of imperfection. And, working out from this studied tolerance, to try and find solutions that largely work well given constraints of site, time, and budget that affect most circumstances.

Now, in most contemporary landscape garden environments, watering systems fall into two basic divisions: first spray or overhead irrigation and secondly drip, subsurface, or micro irrigation. Each of these types of watering systems has stronger and weaker characteristics. Let’s take a brief look at each.

Spray or Overhead Irrigation

Spray, or overhead irrigation refers to the method of dispersing the water, which is through the air to the soil and plantings. This is accomplished either through fixed or adjustable nozzles nested in sprinkler bodies that spray the water out in circles or partial circles in radii varying from 2 feet to 20 feet. Typically these sprinkler heads (nozzle and body combinations) are mounted either permanently above ground or in a below ground pop-up body which retracts the nozzle and riser back into its housing after watering, to decrease its vulnerability and to eliminate what can be visual clutter.

For areas requiring water distribution larger than 18–20 feet, there are various other devices that throw water in considerably larger patterns. Most of these sprinklers nowadays are known as gear drives or rotors and they are generally housed in below ground bodies that lift when charged with water and then spray through one or more nozzle ports to effect a distribution over the area to be covered. Most of these heads have a sizeable range of pattern and distance over which they may be adjusted or nozzled for water delivery. There are gear drive rotors, that vary in size and quality to address differing ranges of spray from 15 to 20 feet on the small size, all the way to 150 feet on the larger end.

There are also still available the somewhat antiquated but oddly charming and effective, impact type heads known generically as “Rain Birds®.” These are usually mounted permanently above ground, but they are also available in below ground housings, known when I was young as a “bird-in-a-bucket.” Also available for the 15–35 foot range are the useful and entertaining hybrid-like stream rotor heads that are especially valuable for sites that are hilly and erosive, have low pressure or low volume, are non-lawn applications; or for sites having an existing system that may be in need of improvement through the conversion and remodeling of either a spray, drip or gear drive system.

Overall, in a sort of sweeping sense, my first preference in watering systems is to favor overhead spray systems. If properly installed with good quality components, these systems are both more durable and easier to maintain than drip, micro, and subsurface systems. But overhead systems do have downsides. For example, the spray patterns usually become blocked at some point as plantings grow; their usage can potentially encourage or spread plant diseases if good horticultural practices are not followed; they may damage adjacent buildings or cars, etc., through overspray if improperly adjusted (and they not infrequently go out of adjustment); and potentially, they may waste water due to poor adjustment or an improper watering time span.

Drip Irrigation

Although ancient in practice, modern drip irrigation traces back about 150 years with further modernization in the 1950s and then continuous further refinement up to the present. About 40 years ago, various proprietary drip irrigation systems started to become available commercially to the landscape trade and there has been subsequently a steady growth in their use around the world. It is hard to deny the simple yet inspired concepts at work in the careful distribution of scarce water directly to root zones with minimal water pressure, flow, or waste. Consequentially, drip irrigation has consistently grown in use and is indeed a highly valuable and perhaps even necessary watering method.

On most of our jobs these days, we have some element of these drip, low-flow techniques in our mix of systems. They comport to irregular or small areas, they may save both water and energy, they can decrease fertilization cost and unwanted weed growth, they may decrease the vectoring of diseases and they do curtail undesirable overspray and evaporative water loss. Here again, however, the downsides of drip irrigation are worth noting.

Many systems are flimsy and highly vulnerable to animals, children, pedestrians, maintenance workers, and various garden variety miscreants attracted to the often frilly appurtenances perched unsteadily and visibly above ground. It should be said also, that because water placement is largely unseen, problems with drip systems may easily go undetected until plants start dying. Additionally, water distribution may be marginal, poor, or even pathological. Water filtration or mineralization issues can cause major failures, and quality systems may actually cost more than overhead installations.

As a craftsman and garden builder I am bemused and peeved both at the innumerable drip systems that I see splayed upon the ground like debris, having the appearance of being crummy impersonations of a water system. The facility with which lumber yards and big-box stores peddle tinkertoy-like components to inexperienced maintenance and landscape personnel, as well as to the noble do-it-yourselfer, has certainly contributed to many professional landscape workers’ scorn of drip systems. It has also soured many property owners who have had these goofy systems installed in their gardens and landscapes and have grown weary of hassling with trying to keep them serviceable.

Subsurface Irrigation

We have found for our uses that the best drip systems for us to install are subsurface systems with inline pressure compensating emitters that are fabricated right within a reasonably durable plastic pipe. While not as tough as schedule 40 PVC, this pipe is considerably more resilient than the common black poly pipe used ubiquitously in drip installations. We are in some situations able to run this inline emitter pipe in a grid pattern or in continuous curving and re-curving lines; however for most applications, we make hoops to circle individual plantings. We may then make larger concentric hoops for larger or established plants. This method serves a naturally growing and expanding root absorption area.

This subsurface system may be installed underground or on the surface of the ground prior to being covered with a permanent mulch to keep it down out of sight, and protected from sun, light freezing, and other common physical entanglements. We trunk out from our valves to numerous ports with schedule 40 pipe and then adapt or transition over to the emitter line. This practice provides a sturdy core structure which may be sourced back to in the future should the emitter piping be damaged or need to be reconfigured as changes occur in the garden.

Having this hard underground piping system as a distribution matrix—the same as what we use for an overhead type system—makes me feel that we are providing our clients with a lasting core of value. Along with high quality valves and controls, we can then provide a system that combines the virtues of drip irrigation with a permanent underground system which may be repaired and revitalized indefinitely, even if the clog-prone emitters and more vulnerable final distribution piping are damaged.

Micro Irrigation

As for micro irrigation, this generally refers to systems for small scale spray and low volume distribution. Micro irrigation is valuable for containers (as may be drip or subsurface); small areas; for low pressure and/or low flow situations; for soils with slow absorption rates; for temporary, semi-permanent or seasonal plantings; and for the remodeling or modifying of existing irrigation systems. These systems involve handy and varied contrivances. For example, nozzles may be fixed or adjustable, spraying or streaming, or bubbling.

These systems seem to generally suffer from similar deficiencies as drip when they are installed inexpertly: vulnerable, poorly distributive, and prone to gradual or rapid deterioration. They may, however, be installed with a greater degree of strength through a blending of a standard rigid pipe underground distribution network and the use of tough proprietary micro-spray sprinkler bodies, or with adaptive widgets which will allow micro-spray nozzles to fit conventional overhead spray bodies.

Irrigation systems, of course, should not be separated from a corresponding knowledge of plants and soils. Which, along with other variables and components of water systems, is beyond the scope of this elementary overview of basic distribution approaches. Valving, filtration, precipitation rates, pressure and flow rates, controls, installation criteria and techniques, cross contamination issues, maintenance, value engineering, freeze protection and hydro-zones all contribute elements of consideration in the development of a well conceived and constructed water system.

These subjects are for most people probably not necessary to become versed in, although, like with most things we get involved with, the more we know the better we are able to evaluate the cost, benefits, and qualities of the services and systems we are regarding. What is important to understand is that watering systems are not a one-size-fits-all proposition. Good irrigation systems need to fit the terrain and, as well, address the other particulars and variables unique to your site—in addition to matching your requirements and resources. There are significant gradients of quality in design, in the material components used, and in the degree of craftsmanship employed in the development of a water system.

All of these particulars contribute to complexity and ultimately to longevity and value. In a sense, it’s a simple complexity, but a complexity nonetheless. Knowing that you (or someone you engage to design and install a water system) need to think about these converging strands of relevancy gives you at the very least a bit of insight into how to proceed with a modicum of economy and intelligence.