Advice for Homeowners
watering Residential LAWNS and Landscaping
This information is intended to be a general guide for watering practices in Lafayette, CO. Creation Landscaping does not provide sprinkler services, however, we install, repair and update sprinklers and drip lines as part of a larger landscaping project.
How much water does a xeriscape Save?
I am often asked how much water can I save with a xeriscape. My answer is usually something like, “… a lot, I don’t know exactly, but I do know a typical Rain Bird pop-up spray uses about 2 gallons per minute, and a flowering perennial emitter uses 2 gallons per hour….”
It’s winter time now, so I decided to sit down and figure out a better answer. I have designed and installed sprinkler systems and xeriscapes for the last 15 years; I should be able to give you an idea of how much water can be saved when you replace a lawn with a xeriscape.
Summary: My front yard xeriscape used 10% of the water my lawn used, and saved 21,000 gallons of water in the first year.
Every variable here is based on my experience in Lafayette, CO. Here, you must have an automatic sprinkler system to efficiently water a lawn and keep it green. In other parts of the country, a lawn will thrive on natural rainfall. The most important factors in my analysis are: what size is the lawn? How often is it watered? What type of sprinklers are used? Is the lawn shaded or in full sun? Is the lawn kept green all summer? The list goes on… I will apply the following assumptions to get as close as I can to a realistic answer.
My lawn is a 900 SF (square foot) front yard. The sprinkler system employs 12 Rain Bird 1800 pop-up spray bodies with four 1/4 circle (15Q) and eight 1/2 circle (15H) Rain Bird 15 series fixed spray nozzles – the most common front yard sprinkler system in this area. I am using best practice head-to-head spacing and a common sprinkler timer. For GPM, (gallons per minute) I am using Rain Bird’s published flow rates at 30psi (.92 and 1.85 respectively). How often will I run the program? Once every 3 days. How long will it run? I am using 30 minutes to water a lawn in full sun (it would be less if partially shaded). To further simplify the analysis, I am looking at the 18 weeks from mid-May to mid-September (18 weeks, x 7 days = 126 days/ 3 = 42 runs). Here’s the math: 42 runs x 30 minutes =1260 min. x 18.5 GPM = 23,310 gallons of water.
My xeriscape is a typical 900 SF Creation Landscaping design. I put in 25 plantings so each plant will have its own space. I have one compact evergreen tree, two low-growing evergreens, 5 flowering shrubs, 12 flowering perennials, and 5 ground covers. Each plant has emitter(s) on a drip line. A compact evergreen tree usually gets 4 GPH (gallons per hour). A ground cover usually gets 1 GPH. Shrubs usually get 3 GPH. Flowering perennials get 1 or 2 GPH depending on how xeric they are. By sizing the emitter/drip line this way and running it for an hour every three days, each plant gets the water it needs in the summer. In my example, the average planting gets 2GPH. Here’s the math: (42 runs x 1 hr = 42 hrs run time) 42 H x 50 GPH = 2,100 gallons.
Summary: This lawn used 23,310 gallons; the xeriscape used 2,100 gallons. We saved 21,210 gallons. Another way to say it, the xeriscape used 9% of the water that the lawn used.
How much money will my new xeriscape save on my water bill? The answer depends on a whole different set of variables. Our water rates are based on usage. The first 3,000 gallons (tier 1) are one price, the next 7,000 gallons (tier 2) are another price, and so on. According to the City of Lafayette water rates page, a typical single-family household uses about 3,000 gallons of water per month for normal indoor consumption. If you are watering a large back yard, the next 7,000 gallons would be billed at tier 2. Assuming your front yard is billed at tier 3 rates, in 2024, you would be paying about .01 (cent) per gallon. So, if we use the 2024 tier 3 rate, 21,210 x .01 = $212.10 saved.
I am sure you see that every situation will be different. Some people might be thinking, I thought I would save a lot more money than that; it would take 40 years to pay for a $9,000 xeriscape at this rate. Maybe. You might also consider, your lawn could be larger, your water rates will higher in the future, you won’t have to buy gas for your mower or pay someone to mow any longer.
Watering your New Xeriscape on a drip line
With our drip line/emitter set-up on your xeriscape, the ideal program is about 1 hour every three days throughout most of the summer, when high temperatures are in the 80s. Here’s why: For a small evergreen tree or large shrub that comes in a 5 gallon bucket, we would put on 2 red rain bird emitters. The red ones drip out 2 gallons per hour (the black ones emit 1 gallon per hour) so, if you run the drip line for 1 hour, the root ball of that evergreen gets 4 gallons of water – a good soaking. We do not run drip lines more often than every three days because plant roots need to dry out before the next watering. So, for newly established plants (the first 2-3 weeks), and in the heat of the summer (highs 90s -100s) you can run up to 90 minutes every three days. You should never need any more than 90 minutes every three days – and usually only during weeks where temps are in the 100s. In the spring and fall, when highs are in the 70s- you can run your drip line for 30 minutes, and also spread out to every 4 or 5 days.
Winter watering is important, especially the evergreens, especially during dry spells. I try to wait for a warm winter day, and just go around with the hose. If the ground is frozen, just wait for it to thaw. Some people will start up their sprinkler to run the drip line during the winter, But only do this if you know how to drain it when you are done.
After your plants are established (say 2 years after planting) you should be able to water every 4 days in the summer. How do you know if your plants need more water? The best way to tell is to check the soil. Dig down next to the roots of your plant to a depth of 6" and pinch out a bit of soil. If it's soaking wet the day after you watered, cut back. If it's damp, it's fine. If it's dry and crumbly, increase the water.
Some people make the mistake of putting flower pots of annuals, or vegetable garden beds on the shrub/tree/perennial (xeriscape) drip line. Patio pots, vegetables, gardens, and annuals usually need daily watering for them to prosper and so these two things are incompatible. A xeriscape drip line can provide supplemental watering every three days, but if you ask it to water your tomatoes every day, you are watering everything else too much. Mixing micro sprays with emitters on a drip line is an issue because one red drip line emitter puts out 2 gallons an hour, and a red micro spray tip on a stake will put out as much as 25 gallons per hour.
I hope this helps with watering your xeriscape, and don’t hesitate to ask questions if any of this needs more explanation.
Always water new plantings once a month in the winter – for the first two-three years, unless the ground is frozen.
Watering Your Lawn
In Colorado, proper watering with an automatic sprinkler system will have the greatest positive effect on your lawn than anything else that you can do. After watering, I believe organic fertilizer is the second-most important aspect of maintaining a healthy lawn. Finally, how you mow your lawn will make a big impact. This article will focus on best practices for efficient watering of your lawn in Colorado. Before developing a watering plan, check to see if your municipality has watering restrictions in place. In Lafayette, you may not water between the hours of 10:00am and 6:00pm. This is not a problem for most homeowners because it is better to water in the early morning, and an automatic sprinkler system will do just that.
A word about sprinkler systems: If you have an automatic sprinkler system, it must be winterized every fall to avoid freezing and cracking the copper and brass plumbing and back-flow preventer that feed water to your system. The average last freeze date for Denver around May 15, that means the last hard freeze that could break your system is usually mid-April. I suggest waiting until at least May 1 to start your sprinkler system. The average first freeze date for Denver is around October 15, and the first hard freeze is usually not until after October 30, to be safe, try to have your sprinkler system winterized by October 1.
New Sod: If you have new Sod, it will need lots of water during the first 4-6 weeks. The rule of thumb is to keep it damp so that it does not dry out. Sod watering is highly dependent on weather – the average need is about 5 minutes in the morning, and another 5 minutes in the afternoon. Watering restrictions may force you to hand-water sod during the day until it is established.
Principles of watering: Deep watering (6-12″) and less frequent watering (every 3-7 days) is the only way to achieve a super healthy lawn and conserve water at the same time. Deep watering improves plant health because the grass roots “chase” the water down. As your deeply watered lawn dries out, water is percolating deeper into the soil, and grass roots are chasing the water down, effectively aerating your soil – and eventually eliminating the need for aeration. The principle of deep and infrequent watering allows the lawn’s roots to dry out in between waterings, and this is critical to preventing diseases that thrive in the humid areas of your lawn. In Colorado, established lawns should be watered no more than every 3 days. If you put your mind to it, a healthy lawn can be watered as infrequently as every 5-7 days. A deep root system is essential to a drought-resistant, disease resistant, water-efficient, weed-choking, green lawn and the key to deep roots is deep and infrequent watering. The easiest way to see how deep the roots of your lawn are is to check the soil; push a spade down into your lawn and look; the deeper the better. If your spade will not penetrate the soil, your lawn is too dry. If you have been watering every day, you will find the grass is green on top but your lawn’s roots are shallow because they cannot grow in the mud underneath, and you will almost always see disease in a lawn that is not allowed to dry out in between waterings.
Timer Settings: Using a cyclic or interval setting on your timer is more efficient than picking days of week although sometimes, this is not an option (such as when mandatory watering restrictions dictate specific days of the week for watering, or your timer does not offer this function). Although I often start with every 3 or 4 days, it is possible, over time, to water as infrequently as every 5 days or more. Watering your lawn at night will reduce evaporation and save water so we usually set watering times to end by 6:00 am. To do this, figure the longest run times you will need during the heat of the summer and work backwards. Example: if you will be watering for a total of 4 hours in July and August, start at 2:00 AM so you will be done by 6:00 AM. I usually set timers to start at 12:00 am, and this usually provides enough time to get all the watering done before the sun comes up. Water application rate is crucial for clay soils. If you water your lawn all at once, the soil will not absorb the water fast enough, causing run-off. Address this problem by breaking up your zone watering time with soaking time. Instead of starting program A at 12:00 AM, and watering zone 1 for 30 minutes, zone 2 for 30 minutes, and zone 3 for 30 minutes, break each 30 minute zone watering time into 3 separate 10 minute watering times by setting three start times for each zone and setting the zone run time to 10 minutes, like this: Program A, start time #1: 12:00 AM, start time #2: 2AM, start time #3: 4:00 AM (and zone watering times are now set to 10 minutes to get a total of 30 minutes of watering). These intervals give the soil a chance to absorb water more evenly and deeply, and by watering this way, run-off is minimized. This method can also reduce brown spots, because the soaking method gives water a chance to move horizontally as well as vertically. TIP: Make sure you are in the right program before you start setting your timer – most timers provide for 3-4 programs (A,B,C..). Using the soaking method can make changing your schedule very tedious. Since you will need more water in the summer and less in the spring and fall, change the frequency from every 5 days in the spring and fall to every 3 days in the summer. If you still need more water in the summer, turn up the seasonal adjustment from 100% to 125%, so that you are watering deeper, but not more frequently than every three days.
Many timers have a seasonal adjustment feature: Let’s say that in June, you are running each zone 3 times, for 10 minutes each, for a total of 30 minutes. In the cool months like May and September, if you adjust the percentage to 50%, and each run time will be shortened by half (5 minutes) and so each zone will run for a total of 15 minutes. Likewise, in July and August, when your lawn needs more water, simply turn up the percentage to 150% and now you are watering for a total of 45 minutes. Again in the fall, you can adjust the percentage back down again. Using the seasonal adjustment feature is much easier than changing each run time time for each zone. Tip: if you leave your timer plugged in all year and just turn it to “off” in the winter, all of your programs will still be there in the spring.
Sprinkler Heads: Most traditional residential pop-up sprinklers have a fixed spray pattern and put water on too fast. This provides another opportunity for the homeowner to save water. Some sprinkler manufacturers like Hunter offer rotating pop-up sprinkler heads that apply water more uniformly and at slower rates than traditional pop-up spray heads. Additionally, these heads can reduce evaporation because they put the water on in bigger droplets than pop-ups.
Sprinkler head adjustment is another key to a water-efficient lawn. In many locales, it is illegal to have water running over the sidewalk or other impermeable surfaces so making sure your sprinkler heads are adjusted properly will save water and reduce brown spots. Many times, brown spots can be addressed and even eliminated with proper sprinkler head adjustment. The installation of a rain sensor provides another opportunity to save water because it shuts down your sprinkler system during and after a rain event. Rain sensors can be purchased wherever sprinkler system components are sold and they are fairly easy to install. See local city information and rules for watering lawns and landscaping in Lafayette.