Drought, Soil & Your Backyard

Hooray, we’ve just experienced the first significant rainfall of the winter in the San Francisco Bay Area. But was it enough to break us from our recent cycle of drought. Unfortunately NO.

In fact, we may be in for an extended period of much drier years to come in the future. According to UC Berkeley paleoclimatologist Lynn Ingram, California hasn’t been this dry since 1580. If that doesn’t alarm you, it should. Our water management infrastructure was created primarily in the last century when the climate in California was milder and wetter than previous periods in geologic history. Maintaining water supplies during decades of severe to extreme drought will require a decentralized parcel-by-parcel approach aimed at saving every drop from every yard and business.

So what does this mean for landscape professionals and gardeners? In short it means a 180 degree shift from the 20th century view of moving water from yard to curb and then storm drain, to the current view of capturing, filtering, and reusing as much water as possible on site with little or none escaping as runoff. It also means that we seriously reconsider the merit of every home and business having a lush green lawn and other thirsty plant materials not suited for our semi-arid climate.

To jumpstart the move to measures that will help all of us sustain our landscapes during a period of prolonged drought, I offer the following eight tips.

1. Lose Your Lawn (LYL)

It’s no secret that 70% of residential water use is for landscaping, and the biggest gulp of that swallowed up by turf. It should stand to reason then, that the easiest way to reduce home water use is to lose your lawn.

The days of the lush green escrow lawn are over! Future water use regulations are likely to prohibit conventional turf in landscapes, except in very special cases (and at extremely high cost). You’d be wise to make the switch from conventional turf to drought tolerant and native species now rather than be mandated to do so in the future. It won’t be long before a new breed of enforcement officers emerges to lay down the law on lawns and water waste.

drought resistant landscaping

Replace your lawn with drought tolerant and native plants. Image by: Beth Muramoto

If that doesn’t convince you, then maybe the impact on the value of your property will. I predict that within a decade homes and businesses that continue to maintain a lawn will be have a market value significantly less than similar properties where the lawn has been replaced with native plants.

If you need additional incentive, consider the number of lawn conversion rebate programs available to residential and commercial property owners offered by water districts and municipalities throughout the Bay Area. With rebate amounts ranging from $500 to as much as $20,000 it’s worth taking the few minutes needed to learn about the program in your area and whether you qualify. It’s important too that you do your homework before you run out and start killing the grass. Most programs require an on-site before and after visit and have limits on the total square footage of converted lawn eligible for a rebate.

2. Upgrade Your Irrigation System

Many residential and commercial properties were constructed with irrigation system controllers that apply water based upon time of day and day of week without regard to actual weather and soil moisture conditions. These 10-minute a day, 7 day a week controllers are no match for today’s modern generation of “smart” controllers. If you need a comparison just think back to the days when a rotary phone was hanging in your kitchen and then reach into your pocket for that mobile masterpiece of communications technology. You get the idea.

Smart controllers use real-time weather conditions, and in some cases soil moisture, to determine when irrigation is needed. Installation typically includes a programmable controller and weather sensor array (sunlight, temperature, rainfall, relative humidity, wind speed). The task of installing one of these water wise sentinels is best left to a irrigation pro like a Bay-Friendly Qualified Professional (BFQP) who has the training and experience needed to get the job done right. For a complete list of BFQPs in your area go to: http://www.bayfriendlycoalition.org.

An example of a “smart” irrigation controller equipped with real-time wifi weather sensors.

An example of a “smart” irrigation controller equipped with real-time wifi weather sensors.

Similar to the LYL rebates, many water districts now offer smart controller upgrade rebates. Some districts will even supply the smart controller coupled with a rebate for professional installation. In most cases, the cost to upgrade is fully recovered (or nearly so) by the rebate. Once again, it’s important to consult with your water district before initiating an upgrade. Not all smart controllers are created equal, and not all smart controllers qualify for a rebate. Remember to do your homework first.

3. Water Deeply

standard drip and deep drip emitters

Comparison of subsurface irrigated area with standard drip and deep drip emitters.

I’m sure that you’re familiar with sprinklers that put more water into the air and on the street than into the landscape. This is a common problem that results in a huge waste of water. Devices that deliver water to the landscape as a spray including the most efficient sprinklers, put moisture into the air instead of the soil.

You can correct this by converting the sprinklers in your landscape to deep drip irrigation.  Unlike standard drip emitters that apply water at or near the soil surface within a limited area, deep drip spikes deliver water from a few inches to several feet into the ground.

Getting water deeper into the soil profile will stimulate your landscape plants to develop a deep root system. Plants with deeper more developed root systems respond much better when water becomes less plentiful. Deep drip stakes have the added benefit of not needing to be moved as often as plant materials grow.

deep drip stake

The deep drip stake shown in this image delivers water at the root zone 2 ft. into the soil profile. Deep drip stakes come in a variety of lengths including those long enough to irrigate trees.

4. Capture Every Drop

Arguably the most significant change in landscape water management is the emphasis on capturing, filtering, and reusing water where it falls. As drought conditions persist, rain gardens, rainwater catchment, and gray water systems will become the norm in landscape design.

You can get a jump on the trend by becoming an “early adopter” and incorporating one or more landscape water saving features into your yard now. These include “sculpting” your garden to include a network of small depressions for collecting rainwater and disbursing it throughout the site without the need for mechanical assistance. In other words, letting gravity have all the fun moving the water that you’ve collected.

 

Harvesting every drop of available water

Harvesting every drop of available water is the key to sustaining your landscape during a prolonged drought.

 

example of a residential rainwater harvest system

An example of a residential rainwater harvest system.
This model holds 1,200 gallons.

If you’re thirsty for more, consider installing a rainwater catchment system with a cistern. Doing so could have you harvesting 14,000 gallons or more of rainwater off your roof that otherwise would have gone down a storm drain.

This is water that can be used to irrigate your landscape, protect your property against wildfire, and sustain your life during a disaster. Watch for insurance companies to start offering policy discounts for homes and businesses having rainwater harvest systems

If you want to take water harvesting to the next level, consider installing a gray water system. The focus here is making the most of the water resources that you already have available including the water in your household plumbing.

Remember that all water is recycled and that you need to make the most of each drop as it passes through the recycling process. There are no “new” sources of water to be found. All that we have is already here, and we need to make the most it.

greywater-system

A gray water system directs reclaimed household water to the landscape for irrigation.

One last point on capture, filter, and reuse. Be sure to check your local building code before you become a water harvest crusader. Codes have a tendency to lag behind allowing what ecosystems do naturally.

5. Plant Water-Wise

When it comes to planting with water use in mind think drought tolerant and native species. Selecting the right plants can be a bit tricky, but thanks to a new labeling partnership between the Bay-Friendly Landscaping and Gardening Coalition and Devil Mountain Nursery the job of identifying drought tolerant plants got a lot easier. Plants bearing the “Drought Devils” label will take the guesswork out determining which plants will survive under drought conditions.

Beyond looking for label identification of drought tolerance, plan to purchase your plant materials in the smallest container size possible. Ideally you want to buy plugs, but any size up to 1 gallon is acceptable. Why small plants? They need less water, experience less transplant stress, and consequently will send roots looking deeper and farther out for moisture. Also be sure to space your plants far enough apart to accommodate growth over time. Plants that are spaced too closely tend to have limited root development and are prone to pests and disease.

To be plant water-wise in an established landscape, divide or thin plant material to remove those that are stressed or diseased.

 

drought resistant landscaping

Maintain space around plantings to encourage deeper root development. Image by: Beth Muramoto.

6. Stop Fertilizing

Drought is not the time to apply fertilizer (either synthetic or organic). Fertilizers promote new plant growth that requires additional water. In the absence of the additional moisture needed to sustain the new growth, the plant will become stressed, creating an opportunity for invasion by pests. This isn’t a pretty picture!

To make the situation worse, fertilizers can “burn” plant roots and create a buildup of salts, particularly sodium salts, that cause soil aggregates (soil structure) to breakdown. Loss of soil structure leads to erosion, compaction, loss or porosity, higher bulk density, and other soil ills. There is a better way to provide your landscape plants with needed nutrients without the use of fertilizers, and I bet you know what it is (if you’re a faithful reader, you certainly do).

7. Apply Compost

The single best action that landscape professionals and homeowners can take to improve moisture retention in soil is the addition of 1-2 inches of compost (organic matter) every other month. A 1% increase in soil organic matter quadruples the water holding capacity of the soil (textural differences aside) while also feeding soil microbes responsible for moving water and nutrients to plant roots. And, in case you’re wondering, compost retains soil moisture as well as, or better than, all of those polymer-based products that are now being marketed as magic water magnets. Don’t be tricked by slick marketing schemes. My advice is to stick with a stable and mature, high quality compost like WM EarthCare™ Homegrown Compost, to improve moisture retention.

Remember, however, that to protect the moisture retention of compost it must be covered with at least three inches of organic mulch – recycled wood, straw, pine needles, or shredded newspaper. Failure to apply an adequate layer of mulch on top of compost will greatly diminish its water holding capacity.

Everyone together with me now: Compost! Compost! Compost!

8. Apply Mulch

With compost being tip #7, is follows that my final tip is to apply mulch. Lots of mulch! The easiest way to achieve immediate water savings in your landscape is to apply at least three inches of recycled wood mulch. Mulch not only aids in soil moisture retention, it also inhibits weed growth, moderates soil surface temperatures, guards against soil from erosion, and a long list of other benefits.

The point is: Mulch! Mulch! Mulch! And do it now!

If you have a landscape or gardening question that you’d like me to answer, send it my way via email at: sandrews@berkeley.edu.

Keep thinking rain, and make the most of every drop!

~The Soil Sommelier