Rain Water Harvesting - The Good, the Bad and the Bunyips.

The Monsoons are supposed to be coming, hopefully. When they do, how much water will remain on your property? Will it cause problems on your property like flooding, erosion or foundation settling? If it happens to be a big rain, how long till you turn your irrigation system back on? Two, maybe three days?

I recently attended a very interesting seminar here in Phoenix. The topic was Rainwater Harvesting. If you live in Phoenix you may not know much about rainwater harvesting. We seem to have the attitude that water is cheap and plentiful, and it is thanks to the CAP. But this isn’t the case most everywhere else in Arizona. Tucson, for instance will be mainstreaming rainwater harvesting into their city development plans very soon. Starting this January all commercial projects in Tucson will have to provide 50% of the landscape irrigation through rainwater harvesting.

This is big news and no small step for any municipal water district. But what do you know about rainwater harvesting? Would you like to know more?

Well, the seminar was basically an introduction to an on line information module just now available for free through the University of Arizona, The Technology and Research Initiative Fund (TRIF), and The Water Sustainability Program. The actual module site was created by the Arid Lands Information Center team: Carla Casler, Theresa Crimmins, Damian Hammond, Chris Hansen, and Katherine Waser.

The goal of the site is to provide Arizonans who are new to rainwater harvesting with the tools and information they need to begin planning their own rainwater harvesting system. They discuss some of the most useful backyard water harvesting strategies, including some that you can implement yourself without a lot of expensive equipment or tools. They even offer a How-To video on Bunyips.

A bunyip is a mythical creature from Australian folklore, but also a very old and useful tool for grading. Personally I’ll stick with my laser level, but bunyip is such a cool word, I had to work it in.

You must register, but use of the module is free. Check it out: Simple Techniques for Back Yard Water Harvesting.

Have you ever noticed how happy your plants look after a good rain? It isn’t your imagination. Your plants prefer rainwater. I encourage you to get your feet wet (pardon the pun) and try a small project. If you have children, they will love it and it might get them away from the game console for a little while.

Landscape Irrigation without the Numbers – Step one.

Step 1) Discovering your watering rate:

Basically in step one, we want to figure out how many minutes it takes your system to wet the root zone of your plants.

First we need to let your yard or garden dry out a bit.

Then you will water it once for the normal amount of time.

Then you will measure the depth of the wetted area under your plants.

Let the soil in your yard or garden dry out for the regular interval between irrigation cycles, plus maybe one or two extra days. Watch your plants carefully. You may need to hand water certain plants, especially your pots and containerized plants that begin to stress.

When you are satisfied the ground is dry, or when many of your plants are beginning to wilt, turn your irrigation system back on manually for one cycle. Everything should get the normal drink of water. If your plants normally get 30 minutes, run it for 30 minutes. The best time to do this is early in the morning or just after the sun sets. Wait about an hour after the normal watering cycle is finished, then grab your soil probe. You are going to gently push it into the soil about 4” - 6” away from the drip emitter or bubbler of each plant. Remember, I said gently.

**** But first, a word of caution. ****

Every yard has utility lines, water, electric, phone, cable TV, natural gas and sewer. Add to that, landscape irrigation pipe and hoses, pool piping, landscape lighting, electrical for outdoor kitchen, patios, fountain pumps, drainage line, etc. Anytime you dig or push a soil probe into the ground, you should understand where these things are and take proper precautions not to hit any of them. There is a chance that you could make contact with an electrical line and receive a lethal electrical shock. Never use a hammer or anything to drive or pound your soil probe into the ground. Also make sure your probe is rounded or blunt on the tip. This way, if you do bump a drip line or pipe, your probe will probably slide off rather then puncture or cut the line.

Always call before you dig or excavate! Arizona Blue Stake will mark your utility lines in your yard for free.

The soil will be wet so the probe should push in easily. My wife can do this with one hand. If you have very little hand and arm strength, you might need to use two hands, but be careful. If the probe doesn’t go into the soil easily, don’t force it. You can move to the other side of the plant and try it, or move to another plant and try it again. I have been using soil probes for a very long time and I have never damaged anything. However, I use them very gently as if I expect I might hit a drip hose or pipe.

When the probe hits dry soil, it will be become harder to push it down. Don’t force it. You are measuring the depth of the wet soil only. Hold your finger, or mark your probe at ground level and then pull it out. This is the depth of the wet zone or soil reservoir your irrigation system has provided for your plant.

The 1, 2, 3 rule works well for mature plant root zones. Here in the desert, ground covers have a root zone about 1 foot deep. Shrubs feeder roots will usually run about 2 feet deep. Tree feeder roots usually run about 3 feet deep. Lawns should be watered to about 8”.

Adjust your timer till you have the right wetted depth for most of your plants. You don’t have to be perfect, just get close and write down your results. I usually make a simple drawing with the wetted depth for each plant along with the number of minutes used on the timer. This is very close to the amount of minutes you will use to irrigate each given zone or valve.

Don’t go out and buy a bunch or drip emitters and try to balance each plant just yet. In the next step we will talk about proper wetting of the entire root zone and balancing the water rate at each plant. You may need to change or add some emitters in this next step. That will be when you can go out and buy stuff.

Work through your watering depths and check back here for Step 2. Wetting the Root Zone.

Landscape Watering by the Numbers

Ok, it’s mid July and the Monsoons haven’t made much of an appearance yet. Recently we’ve had the hottest days of the year (so far) and some of your plants are probably looking a little sick. Many of us actually over-water this time of year because we worry about our plants out there suffering in this heat. So, in the spirit of hot air and since July is now Officially National Smart Irrigation Month, here is the beginning of a series on how to water your plants.

There are some pretty good guides and pamphlets out there that cover the subject very well.

This is the best pamphlet I’ve seen so far and you can download a PDF here.

The problem is these guides take time and to read and follow and we are all busy, right? Sometimes it’s just easier to add more time to the controller. And so this is how it happens that people get big water bills and many times sick plants from over watering.

Would you like a quick start guide? OK!

I have a fairly simple process that is part of a program I use on almost all of the properties where I manage the Landscape Irrigation. I have developed this process because everyone’s yard, garden and landscape is unique. Every yard is a micro-climate all its own. Plus the irrigation system is almost always different too. Sometimes they need some work, but I’ll cover that in another article.

However, the goal is almost always the same. We must deliver just enough water to wet the root area of the plant plus just a tiny bit of extra. Then to let the root zone dry a bit, then repeat. I’ll show you how to do that in your yard in three steps.

You will need a soil probe for this process. I think every gardener should have one. It doesn’t have to be spiffy. A very long screw driver or a piece of rebar with a point on one end works great. A three foot long soil probe is best, but a 24” probe can work. I use an old piece of rebar with a “T” welded to one end and grind stripes every 6”.

Here is a picture mine. It’s old and not real trendy.

You don’t need a “T” on the end. Rebar bent to an “L” on the end will also work great. I think almost any hardware store that sells rebar, sells shorter pieces and can bend an “L” on one end for you. Concrete installers use bent rebar all the time to brace concrete slabs. Very long screw drivers are cooler looking but they can be expensive.

**** A word of caution. ****

My soil probe is all metal. Yours doesn't have to be all metal. I have used all metal soil probes for many years without a problem. Used properly, they are about as safe as any other tool. However, there is a chance you or I could make contact with an electrical wire, conduit, irrigation line, sewer line, or water line that has been buried in your yard. There is a chance you could come into contact with a lethal amount of voltage. If you decide to use a soil probe of any kind, use it at your own risk. Never use a hammer or anything else to drive of force your soil probe into the ground.

In the next article, I will cover the proper use of a soil probe. Used properly, I believe they are about as safe as any other tool. There are some really cool soil probes on-line that range from $80. on up. There are a number with fiberglass shafts that should insulate you in the event you strike a high voltage line on your garden.

So go find one in the garage, build one or buy one and then come back for step one.