Here’s an important bit of advice that you will not see anywhere else. It could make all the difference in the success of your landscaping and in your water conservation efforts.
Conventional wisdom in the landscaping profession is that when the weather changes, you should adjust the amount of time that you water your plants, putting down more water when the weather is hot, dry, or windy, and less water when it’s cool, damp, or rainy. Nothing could be more wrongheaded. Here’s why:
First, watch this one and a half-minute video, then come back and I’ll explain why the information in the video, and all similar information that is commonly available, is foolish and dangerous. Here’s the link for the video: http://www.youtube.com/watch?v=VZyPqn7J2hs.
OK, that seems helpful, right? Well, it’s not only not helpful, it’s downright reckless. The water budget feature adjusts the watering time by a percentage, up in hot weather and down in cool weather. It sounds perfectly logical. But…by adjusting the watering time, the depth of watering changes, so that sometimes the water will go twice as deep as usual and other times it might only go half as deep as usual. The roots, and therefore the plants, don’t get what they need. And because the system won’t come on until the next regularly scheduled watering day, which is NOT changed by the water budget feature, the plants have to endure perhaps DAYS of parching weather when they really need a drink this very minute. Water is wasted and the landscape suffers. This is really stupid, don’t you think?
So what SHOULD you be changing to account for the difference in demand caused by variations in the weather? You should be changing the FREQUENCY of irrigations, going from, for instance, two days a week in normal weather to three days a week in hot weather or one day a week in cool weather. After all, isn’t that what you would do if you were watering by hand? You would say to yourself, “Oh, it’s hot and things have dried out more quickly than usual. I’d better get out there and water!” You wouldn’t wait until your “regular” watering day and then apply twice as much water as usual. So if you know better, instinctually, then how come the people who make irrigation controllers, the people who install them, and the people who teach other people how to use them, don’t get it? Beats me. It’s just one of those things that seemed like a bright idea to some engineer who didn’t know squat about horticulture, and nobody – nobody – has ever bothered to question it. And we’re talking about tens of thousands of knowledgeable professionals here. By the way, there may be a controller out there that allows you to easily change the frequency of watering, but I haven’t found it yet.
OK, so now you’re smarter than virtually every landscape professional on the planet. What are you going to do about it? That’s right. You’re going to trot out to the garage and stick a piece of duct tape over that “Water Budget” button on your timer and never, ever change it from 100%. It is set at 100% isn’t it?
Next, you’ll need a way to vary the frequency of watering. This is where things get a little sticky, because you’ll have to go into each program on your controller and add or remove days. For instance, suppose your lawns on Program One are set to water two times a week during “normal” weather. If the weather heats up, then add another day, going from, say, Monday and Friday to Monday, Wednesday, and Friday. And when the weather cools down? You guessed it: Cut it back to once a week. That’s not hard to do, but it’s a good idea to plan it out in advance to be sure you don’t create overlaps that would cause two valves to come on at the same time, overtaxing the ability of the water supply to operate the system at adequate pressure. That’s no big deal either; just be sure each program has enough open time during the week to do what it needs to do.
Next you have to keep an eye on things to be sure your new settings are actually delivering the water at the point when the plants actually need it. If you see signs of drought or oversaturation, tweak your schedule as needed. It’s really not that hard, just a matter of observing your garden as any good gardener will do. You see, those controllers aren’t very useful without the wisdom and watchful eye of the gardener to make them do the right thing. Automating the system is not the same as optimizing the system. The former is handled very well by the controller; the latter is up to you.
The rewards for better water management are lower water bills, more money in your pocket, healthier plants, and lower negative impacts on the environment. A little effort pays you back generously. Give it a try!
Or, you do what I do and just drag out the hose.
Exactly. Sometimes low tech is the best way to go. I’ll let you in on a little secret. I don’t have an automatic irrigation controller. I have a drip system that operates manually, and in fact I do the majority of my watering by hand. The folks at the American Water Works Association, who ought to know, assert that hand watering is the most efficient method of irrigation. So you get a gold star for being very sustainable (the environmental impact of making a garden hose is much less than the impact of making a controller and valves and all that, plus hoses don’t use energy) and sensible and water-wise. Congratulations!
And the best thing about hand watering is that it “fertilizes”, too. There is an old Chinese saying that the best fertilizer is the farmer’s shadow.
Perhaps we “pros” who don’t use automatic irrigation need to reveal ourselves en masse.
YES, PLEASE! There is a deeper question, which is: Why do we need irrigation systems at all? Aren’t they a sign of an ill-adapted design? (Well, I will answer my own question by saying that sometimes irrigation systems are a good idea, but that’s a whole other discussion.). Sensible people need to speak out, to the professions, to the manufacturers, and to the public. Let ‘er rip, Maureen!
Love the blog Owen!! I agree DRIP is the way to go!! One of the best controllers I have seen out there for the home owner recently is the Rain Bird ESP-SMT http://youtu.be/O1V4DYiFWJM The problem is not just cost but that to get the proper benefit is allow the clock to do its job vs. certain water days as required by law in areas.
I know we have all seen it – Its raining out yet the irrigation is on. Sure there is a mini click but it is hidden under the trees and does not perform properly. I know my neighbor whom I have educated says, “Its my day to water so I am going to water no matter what!”
Keep up the great posts!!
In my 25+ years of designing gardens, I have never yet specified an irrigation system. I have always believed that planting the right plants in the right places in the right way at the right time, to give them an excellent chance of survival and the ability to flourish. I always recommend watering with a watering can from a water butt(in small gardens) or a hose, and only if really necessary, usually as the plants are establishing and less able to cope with stress. Watering is one opportunity to check each plant in turn and give them some attention, something that is as important as the basic physical requirements of good soil, warmth, water and light.
BAN RETIC! Love the discussion.
I live in Perth Western Australia and am doing experiments with establishing a system that intensively and locally converts ‘waste’ to food.
I now call it Sustainable Urban Nutrition (SUN). Reducing food and waste miles. A network of food gardens within 1km of every house.
It operates as a partnership between local government, business (food and waste) and community : a cross between a commercial market garden and a community garden.
I have made a short video (http://youtu.be/B3mLTbNGMXw) that shows my latest garden beds that uses my own planting mix laid out to form 1m high letters and words with my own natural seeds coming up to highlight the letters in ‘natural green’.
The ‘page’ is mulch that surrounds every letter in a ‘word bed’. I doubt they are large enough to be seen using google earth, but probably with aerial photography.
The words are from an Australian song about Aboriginal land rights and an amazing Aboriginal man : “From little things”.
This could be a new form of sustainable advertising altho I intend using it for more writing : my next one will be only 3 letters about 4-5m high – I reckon that will be visible from google earth.
Then out to the farms with sunflower seeds, tractor and a seeder.
You can follow this over time (slowly) by subscribing to my haywoodfarm youtube channel or saving the google maps reference point on the little things vid.
And, elderly people and disabled should be allowed to use retic although I think hand watering is one of the most sustainable forms of therapy and nature connection there is.
This is particularly true for well-draining soils (like my sandy loam). Increasing watering times mainly just sends more water below the root zone, kind of a waste of energy. (I get the water back because it just returns to the water table aquifer that supplies my well.) The only useful response to dry weather here is to increase watering frequency.
With fine-grained soils (silt and clay), increasing the amount applied is more likely to cause local saturation, which isn’t good either. Much safer and more effective to increase frequency instead.
Owen, after nearly 30 years of practice I will venture to say in general my fellow landscape architects and irrigation designers and the engineers/architects I work with daily are guilty as you charge. Controllers are nothing more than a property owner’s time-convenience. I’ve sang countless tunes at my clients that if you have an irrigation system, then the controller should be “off” or “unplugged”…unless you go on vacation and the in-laws’ green thumb is in question (they typically won’t let me not spec one, not to mention local codes require an irrigation system to be “automatic”). Fiona has it going on: put the right plant in the right place and your water conservation and management issues will become simple and commonplace.
the key to water retention is maximising the organic content of the soil
Thanks for your comment. Actually there is plenty of evidence that gardeners add too much organic to their soils. It’s really the subject for another article, which is on my list. But organic matter can actually decrease water holding capacity under certain circumstances. Long story. I’ll cover it one of these days, so stay tuned.
Look fwd to reading it. I like ur stuff on water. There is of course a difference between perrenials and annuals – in my orchards we used to water as few times as possible as much as possible anytime after flowering. Encourages max root development and production. http://youtu.be/B3mLTbNGMXw
Rain Birds ET Manager Series uses a Managed Allowable Depletion model of irrigation scheduling. http://www.rainbird.com/landscape/products/controllers/ETmanager.htm
Hmm. This looks good. Thanks for letting us know about this. A breakthrough, I believe. Cool.
http://www.rainbird.com/landscape/products/controllers/ESP-SMT.htm
This is the weather station controller we’ve been installing on all our jobs. it gives the option to cut back on percentage or to skip watering days. Downfall is that it maxes out at 12 zones.
Great advice (in contrast with that video!) I’ve also noticed that a lot of the irrigation companies are opposed to drip irrigation — which is the most effective way to deliver water exactly where you want it. There’s a lot of bad advice out there; thanks for setting the record straight.