Irrigation Systems; brand recommendations, layouts, and system details.

This is the second of a three-part blog series that will introduce you to all things irrigation including basic principles of irrigation systems, laying out a system, and brand recommendations along with handy tips and tricks!

Part 2: Irrigation system recommendations, system details and layout examples.

In our last post Basics of Irrigation, we covered a few fundamentals of irrigating your garden. This post will cover examples of types of irrigation systems, provide visual examples of what an irrigation layout in your garden may look like, define vocabulary, cover self-installation notes, and provide brand recommendations. First let’s go over some irrigation brands! 

Which brand should I buy? 

Garden Girl’s recommendations for homeowner installation are the Rainbird or Hunter irrigation systems.

In Garden Girl’s experience, Hunter systems hold up better than Rainbird over a 15-year period. Regardless of which system you choose, both of these companies have excellent videos illustrating how to install a system. 

Download your FREE Irrigation Quick Reference Guide

Here are some examples of a Rainbird system layout before we dive into discussing individual components:

Pictured above is a digram of the Hunter Rainbird Irrigation system to highlight the components that are included; PVC Lateral, XBD-80, Tubing Stake with a cap and of course a water system. This is outlined as it shown as it would be set up in a garden bed.

• Layout: Start with the longest side. Create parallel rows to fill the area. Identify supply and exhaust header locations, and connect the lines. In flat areas, lay tubing in straight lines, accommodating curved edges by returning or branching lines.

• Slopes: Lay inline tubing perpendicular to the slope (parallel to contours, not running directly downhill). 

• Edges: Because hardscape edges and limits of planting are subject to wind, radiant heat, reflected sunlight, and other factors that increase evaporation,plants in those areas need more water. Place perimeter lines close to edges, typically ¼ of the regular on-center spacing, but no more than 4".

Here are two more examples of irrigation systems in planting beds with notated components. Pictured left (Rainbird System) Pictured right (Hunter System).

Above is an example of a vegetable bed irrigation layout.

Here is an example of a Hunter drip system in a planting bed.

Let’s talk about the components of an inline drip system.

Controller: A controller is the “brain” of every irrigation system. Wall mount or in-valve-box battery controllers are ideal.

Zone Control Kit: Every successful inline drip irrigation zone starts with three items: zone control, filtration, and pressure regulation.

Valve: A remote control valve is typically used to automatically activate inline drip systems. Alternatively, you can also use a manual valve or even hose bib for non-automatic systems. Irrigate each hydrozone with a separate valve. Hydrozones are areas with specific conditions that affect irrigation, including plant type, spacing, density, microclimate, exposure, and slope.

Please follow all local requirements to prevent backflow and back-siphonage. Filtration must be provided for all inline drip systems, regardless of water supply type. Filters remove suspended particulates that are present even in potable water, which may clog inline emitters. Filters also help reduce biological contaminants. For large or distributed systems, consider a disk filter near the point of connection. This provides a single, easily maintained item in an accessible location. Use screen filters at each drip valve as a secondary level of protection in case any debris enters the irrigation system downstream of the primary filter. Use a filter with a minimum filtration level of 120 microns (approximately 120 mesh, or 0.125 mm). Inline Drip Tubing Inline drip tubing consists of tubing laid in parallel rows. This creates a grid of emitters evenly spaced throughout the entire irrigated area.

Pressure Regulation: All the Hunter inline drip products feature built-in pressure compensation, allowing an inlet pressure of 15-50 PSI.Use a pressure regulator downstream of the valve and filter for mainline pressures exceeding 50 PSI.

Depending on the type of system you buy, you will purchase the appropriate Laterals, Supply Header, Barbed Fittings, AVR Valve, Exhaust Header, Flush Valves, and PLD Cap.

*Note: Flush valves are required on every inline drip system and must be located to provide an outlet from every point in each zone. Flushing regularly is important not only to remove debris and particles from the tubing; the high volume of turbulent water during flushing also helps dislodge biological growth. Flush valves can be either automatic or manual. The Hunter PLD barbed valve is an affordable option. FLUSH VALVE Manual or automatic EX exhaust header serves to equalize pressure and flow between runs of inline drip tubing and provide an outlet path for flushing. The exhaust header does not need to be sized to equal the supply header, but must be able to accommodate the flow rate of the flush valve, without exceeding 5 FPS.

Layout: A typical zone layout consists of supply header(s) and exhaust header(s) with parallel lines of inline drip tubing between. These may be either center-feed or end-feed configurations. Zone design and line layout follow these basic principles:

• Maximum length: To ensure adequate supply to all emitters, do not exceed the maximum run shown in the tables below, including the length of all branched runs.

• Line spacing: Spacing should not be greater than shown in the tables below, but lines may be closer together as needed to equally space lines within a zone or provide additional coverage. 

Note: Increased spacing on the EMITTER FLOW RATE – 1.0 GPH lower third of slopes is an exception to this guideline.

Hunter’s Chart for Emitter Rates

Spacing According to Soil type

When installing a system, please follow the manufacturer’s instructions. 

• Keep dirt and debris away from all pipes and fittings. Protect exposed ends by taping or plugging while assembling other components • Flush the system thoroughly prior to installing the last connections on every header • Ensure that all inline drip products are installed at an even depth throughout each zone • Use loop-type galvanized fabric staples or pins to keep tubing or mat in place • Verify the location of each air/vacuum relief valve in the field, ensuring one is installed at the high point of each zone.

Leak Testing: Test the installed areas for leaks prior to backfill. To test, operate each zone for 20-30 minutes and observe the distribution of water. Wetting patterns should be regularly sized and evenly spaced. If using an Eco-Mat, distribute equally. Repair any leaks that emerge. If this test is not possible prior to backfilling, it should still be conducted prior to planting. Run each valve until wetted areas appear at the surface and make adjustments and repairs as needed.