Your water consumption is dictated by this critical landscape choice between drip and spray irrigation. Several key factors affect your choice. Consideration to the type of plantings, terrain, sun exposure, fire exposure, wind and salt spray exposure are to name just a few. Consider the following when deciding whether to drip or spray irrigate.
Do you need a play surface? Do you really need a lawn? The bulk of your water and maintenance will be spent on it. Consider drought tolerant Bermuda hybrid instead of the thirsty and expensive to maintain hybrid fescues. Spray irrigation is the most reliable method of irrigating. Subterranean lazer tube (netafin), can be used for small scale lawns.
Slope: If erosion control is a factor and groundcover is desired, spray irrigation should be used. It is impractical to attempt to drip irrigate groundcovers planted on close spacing. Therefore overhead spray makes the most sense. Low precipitation heads insure slow percolation of water into soils and lessen their runoff and waste. If the slope is not in a fire hazard area or does not exceed a certain steepness, an organic mulch can be applied over top of soil in a 2”-3” depth. This will be used in lieu of a living groundcover. You will however most likely require a high density of shrub and tree planting to avoid a “sea of mulch”. Always consider exposure to santa ana winds and increased fire exposure when making your selection. Mulch will have to be added each year as well.
Planting Beds Atop Flat or Gently Rolling Terrain
This is the terrain that drip performs most admirably in. The gentle terrain allows for good percolation of water and the myriad of mulched and xeriscape soil coverings bond to the soil without slippage and erosion. Soil coverings from fine particle decomposed granites to chip seal and larger aggregates both smooth and angular may be used atop of a commercial grade weed fabric between drip irrigated plantings. These coverings reduce weeding and water consumption greatly.
Vast outlying areas of larger properties: From a shear expense, maintenance and water consumption stand point, most areas of such nature should be drip irrigated and mulched.
Most fruit trees grown locally enjoy infrequent deep waterings. We highly recommend a separate hard piped bubbler valve or dedicated drip valve for such trees. It may be practical to separate citrus from stone fruit depending upon quantity of trees to save wintertime watering on the deciduous stone fruits. (Peaches, plums, nectarines etc.). Avocados require frequent and much water.
We highly recommend a dedicated drip valve and multi-outlet emitters for clients with many containerized or potted plants. This can be programmed into the controller for automatic watering.
Herb Vegetable Gardens:
Netafin Lazer tubing or soakertube may be the best water conserving method. Combine with heavy mulching, weed fabric or black plastic to help reduce weeding and evaporation.
Spray Irrigation Systems
While easier to adjust and maintain a hard piped irrigation system will also broadcast water across planters and lawn areas, thus increasing your water bill as well. A few things we recommend to our clients are:
- Below grade valve installation in lock top valve boxes to prevent breakage and U.V. exposure.
- System wide backflow prevention – a code requirement.
- Master shut off valve and ball valves at each valve box location to aid in maintenance and repairs.
- Automated digital controlling with rain sensor and remote controls
- 100% overlap or head to head coverage on all irrigated areas to insure even application of water (strongly recommended).
- Low gallonage heads will help increase percolation and prevent runoff.
Drip Irrigation Systems
Initial sizing of drip emitters is critical as well as their location relevant to planted materials. Emitting water to the uphill side, both sides or at the drip line of the plant may depend on species and terrain. Adding more emitters to trees as they grow may aid in their overall health and vigor. Introduction of dirt undetected into a drip system may indeed turn nightmarish as it may easily plug emitters. We highly recommend
- End flush valves.
- Cartridge filters and pressure reducers are mandatory for any drip system.
- Bug caps keeps insects from crawling in and clogging drip pipe and emitters.
- Constant monitoring of the plantings to see if there is a problem with the drip system as visual inspection of the system under mulch is impractical. Long duration of watering is normally the case with drip systems as their gallons per hour delivered to a plant need to be low to allow for percolation without runoff. Careless maintenance workers can easily cut through plastic drip pipes or dislodge hoses by simply walking through beds, so keep it simple!
- Large diameter drip pipe pinned securely to grade with metal staples close together
- Emitters snapped into the sides of drip pipe helps prevent breakage.
- Avoid spaghetti tubing at all costs as we find it does not perform well over time except for use on pottery.