By Melody Kendall

Drought conditions loom again and it is advisable to plan our water use. For home gardens planning may include some research about different watering methods available. Drip irrigation is an easy way to curtail a garden's water use by directly distributing the water to the plant with little or no waste.

To some, the thought of installing a drip system might be overwhelming, but I have found it to be relatively easy. I was initially put off by the math calculations prevalent at each drip irrigation planning information site.  Calculating the water gph or gallons per hour relative to the area to be irrigated, etc., made my eyes roll back into my head. So, I just took the plunge, no pun intended, and installed a system tailored to my personal garden's needs. 

When planning your garden water requirements should be one of the first things to consider.  In a perfect world we would all be able to start from scratch and desire only California native plants along with others that have low water needs.  Native plants would make any irrigation a breeze, and in some cases not necessary at all. But, most of us have an existing garden and have also succumbed to the gardener's curse of coveting plants that are not suitable for our climate. Climate has become a moving target with global warming, but that is a topic for another time. The rule of water-use zones, or hydrozones, usually isn't applicable to most mature gardens. What can a gardener do to efficiently water plants with different water requirements?  I installed a very satisfactory drip irrigation system in my existing mature landscape that has been working well, with some minor repairs & retrofits, for over five years now. 

When purchasing irrigation supplies I have found that buying from the same supplier for all my needs yields the best results in terms of fittings being compatible.  A ½ inch drip line at one manufacturer/ retailer might be just a little bit too big for a ½ inch sized fitting from another manufacturer/retailer.  I'm really big on avoiding blow-outs and the ones I've experienced have come from purchasing the component parts from different suppliers. 

I talked about water-use zones based on the plant's water needs.  In my garden I irrigate by grouping in plant location zones. The city water pressure in our area will not provide suitable pressure to drip irrigate my entire landscape at one time so I have broken my yard into eight watering location zones. These zones are set up to come on one after the other and not ever at the same time. When planning the irrigation system I looked at the whole garden and mentally divided it into those location zones based on availability of a hose bib and how many emitters I plan to have on a particular line. Yes, a little math was involved.  I have come across a hose bib ‘Y' attachment that allows for two systems to be working at different times from one faucet and/or allows the use of a timer and a garden hose to be attached to the faucet for a hose.  I have both configurations working in my system and am quite pleased with the results.

I use the ½ inch drip line and lay it around the perimeter of the area to be irrigated leaving the end towards the faucet, with a little extra length, open and the opposite end closed with a figure 8 end attachment.  

I know each plant and its water needs in each location zone. For example, my hydrangea will need more water than my daylily plant.  When installing the emitters at each plant the hydrangea will get two 2 gph (gallon per hour) drip emitters to the daylily's one and the rest of the plants in this location zone receive the same consideration. My trees will get two concentric circles around their bases containing evenly spaced 2 gph emitters. 

At the end of the ½ inch line closest to the faucet I put a hose bib attachment. I then attach the timer to the faucet and the timer to the ½ inch drip line via the hose bib attachment. I like the hose bib battery operated variety of timer.  They are easy to set up and use, not requiring electrical installation and have very straightforward operation instructions, even with multiple line models.

Now is the time for testing the work. I turned on the faucet and walked alongside the lines looking for leaks and faulty emitters, preparing to get wet. I always come away from any irrigation adventure soaked. I repair any problems and along the entire length of the line, using purchased ‘u' shaped irrigation line staples to stabilize the entire structure.

Now for the timers. I start my timers on a rotating schedule of every other day for 15 minutes. For the first few weeks I keep an eye peeled and gauge any changes on the plants response to the watering schedule. If the plants are doing well I might cut back to 10 minutes and see how it goes. If the plants in an area are unhappy I might increase the irrigation timing to 20 minutes or to 10 min every day.  Each location zone is different and require fine tuning. Add into the mix the extended heat and dryness of summer and I will increase the water as the plants demand. The major point is to regularly monitor both your plants and the system.  

Hopefully, this information has empowered you to try your hand at installing your own drip water system. As with all things in the garden, remember to keep an eye on your lines and emitters regularly to correct any problems quickly.  If you see an unhappy plant do some sleuthing to discover the cause. Simply replacing a defective emitter or adding an additional one might be all that is needed. My quick solution to a discovered leak in the line is to plant a plant in that location, then everyone is happy. 

Further notes:

• To facilitate emitter installation into the different drip lines allow the ½ inch and ¼ inch lines to become more pliable either in the sunlight for an hour or so and/or just prior to installing the emitter dip the line into very warm water.

• When using the hole punch to create a hole for an emitter or ¼ line attachment in the ½ inch line make sure the punch is positioned in a way that the resulting hole is facing in the correct direction. 

• Make sure to purchase a packet of plugs to stop up any holes punched in error.

• Previously I would water in the morning because that allowed the plants to absorb the liquid but not remain wet for an extended length of time. Certain insect pests and plant diseases enjoy a moist environment and morning irrigation helped mitigate problems. But, with our current drought conditions, I am experimenting watering in the evening so that the plants are able to absorb the moisture at their leisure with less evaporation. We have been so dry lately I haven't noticed any increased pest or disease infestations yet.  Time will tell. 

Photo credits: Mel Kendall

Napa Master Gardeners are available to answer garden questions by email: mastergardeners@countyofnapa.org. or phone at 707-253-4143.  Volunteers will get back to you after they research answers to your questions.

Visit our website: napamg.ucanr.edu to find answers to all of your horticultural questions. Please see the our website napamg.ucanr for events including the Las Flores Community Center where instructional events are planned for the last Saturday of the month through 2022. Topics will center on research-based horticultural and climate change issues by featuring water saving plants and soil care. Join us each month at the Las Flores Learning Garden 4300 Linda Vista Ave. for these public education events.  

Information links:

UC drought mgmt

http://ucmanagedrought.ucdavis.edu/Agriculture/Irrigation_Scheduling/Evapotranspiration_Scheduling_ET/Frequency_of_Irrigation/Irrigation_System/

UC California Garden Web http://cagardenweb.ucanr.edu/Drought_/Drought_Irrigation_Tips_/

Santa Cruz County Water Conservation District

http://www.santacruz.watersavingplants.com/Garden-Resources/IrrigationType.php 

UC Davis-Surface Irrigation info http://lawr.ucdavis.edu/cooperative-extension/irrigation/manuals/surface-irrigation

UC DRIP: Watering the Home Garden http://vric.ucdavis.edu/pdf/drip%20irrigation_driphomegarden.pdf

UCMG Napa County https://drive.google.com/file/d/1QEstftNnkfFRceg9EYChBt446Qtpshmb/view?usp=sharing