5 Steps to a Great Lawn, pt 3- WATER

Kill em with kindness might be the theme to the majority of water related issues for ALL plant material, including turf. Just like fertilizer, proper amounts are critical. Too little, it flops over dead, too much and you drown the plant, kick off out of control growth, fungus and insect explosions, erosion, etc. So what exactly should you be doing with your water? Relax, it’s not that tough to get it down and it’ll give you healthier plants while saving you a bundle on that water bill!

We live in a desert- Truthfully, unless you actually do live in the West Desert, parts of south eastern Utah or St. George, you probably don’t. You see, a desert is an area that receives 10” or less of rainfall per year and in some years, zero. This does not likely describe the area where you live and the media campaigns using this tactic, I believe, are actually causing people to over water, thinking that their plants are drying out and about to die each afternoon. The hard facts are that, in Utah, people water on average, 2.5 to 3 TIMES the amount they need to! Triggering diseases, rot, unneeded, weak growth on their plants and wasting away a finite resource. Most of the population of Utah does not live in the desert, but in high altitude, urban communities nestled at the foot of mountain ranges that receive abundant water. So let’s address the water needs of plants and turf specifically, in that setting!

Deep and infrequent- If nothing else sticks with you here, remember those three words…deep and infrequent…for this is the real secret to watering. Why? This is the pattern for developing deep roots that can enable turf to take the extreme heat and ultra low humidity of mid summer here. Yeah, that’s right, you CAN determine what your plants’ roots are doing with little things like managing soil compaction, fertilizer and most importantly, watering. You see, plants put their roots where the water is. This is why a bonzai tree can be grown in a dish or a thousand year old cedar can live where there is only a fraction of water you have available. Ever see a 50 foot pine go down in a windstorm on the news? Notice that it’s always in a lawn and that the root ball is surprisingly small for the size of tree? This is our doing with water patterns. Tree roots all over your lawn, making it a lumpy, bumpy nightmare to mow? Again, a symptom of watering. Why am I choosing trees as an example while we’re talking turf? Because they’re big enough to gain your attention as the casual observer and also it’s important that we think about the other plants in our landscapes that share the watering schedule and how it affects them as well.

How low can you go? Oddly enough, many people think that their grass may put it’s roots 3-4 inches deep, if they think about it at all. Truth is, bluegrass can set roots as deep as a foot and improved tall fescue blends may reach up to 4 feet deep! Why care? Here’s why. Say I wet my grass down on a smoking late July morning. I wet the tops of the grass to “give it a little drink” and figure it’s good to go for the rest of the day as temps rise to 105 and humidity drops to 11 percent. Well, in about 20 minutes or so, that water has evaporated, just like the stuff drizzling down your swamp cooler pads or the sweat off your brow. Unlike those things, however, your grass cannot get more water automatically or by picking itself up and going over to the nearest spigot. So that leaves what? Yeah, the beginning of shutdown. Let’s assume instead that you ran your sprinklers overnight and you were able to wet up the top 8” of soil with a nice deep watering. Now, as the day progresses, the top couple of inches of soil start to bake out, but your plant is sipping as much as it needs from those lower soil depths. It “sweats” off water, cooling itself and takes more in from it’s “reservoir” that you established overnight. Ever notice how walking over to turf on a hot day can lower temps by a good 15-30 degrees? That’s Transevaporation happening, baby and it’s Nature’s airconditioner. Trees do it, your lawn does it, all your plants do it. It’s a major benefit of having plants in an ornamental setting, but it means you are generating a water cost. Now, for the next day or two (depending on your soil type), your lawn is tapped into that moist, lower level of soil and not in need of additional water. By training plants to seek water at this level, they will develop their root system to seek water there, allowing you to bank water for several days at a time, in the hottest points of the year, in an area less prone to evaporation. This is the most effective way to cutting your water and creating plants that can survive the heat of the summer. Water out the top inch or two, it’s dry in hours and now your plant goes into stress in the hot afternoon. Deeply water and train your roots deep from the beginning of the season, you cut your water needs dramatically and your turf becomes stronger and stronger as the seasons progress. This direction of thought is also beneficial to the rest of the plants in your landscape, ensuring enough water at deep enough levels for your trees and shrubs that are often on the same zones.

Time of Day. So we kind of touched on evaporation playing a role in how low we go above, so let’s talk about how the time of day will play a role in how much you lose that way and how much will make it into the soil profile for plant use. Here in Utah, we can have wild temperature swings day to night, sometimes as much as 50 degrees! So, of course, with evaporation in mind, we’d like to aim our watering at the very coolest point of our scheduled water day. This often occurs just before dawn, after solar heat gain has had it’s longest period of darkness to dissipate. The cooling earth and air also tends to drop wind levels, making it easier to put water on target through sprinkler heads. So this is the ideal time. Now, say you have 8 zones that you want to run 40 minute cycles on. 320 minutes of watering that you likely do not have the pressure to run simultaneously. Start at the magic hour just before dawn? Finish at that hour? Put it in the middle? I prefer having my runs finished by 8 am at the latest in order to give as much time as possible for the water I just put down to soak in before heat starts to rise. Because we don’t need to water daily, even during the hottest parts of the summer, I generally break up the landscape into two, maybe even three parts and cut the window form 320 minutes to 160 or even 110 in this example. This allows me to pack the majority of my water as close to the that predawn window as I can, even on large, commercial properties. Of course, this is only possible in the mid summer months by training my plants early on and getting them used to the deep infrequent cycle so that I do not have to water daily at the mid point of the growing season. The point is, the cooler the Earth and air are, the more efficient your watering will be, allowing you to use less water and have more drought resistance for your plants.

Soil,Soil and some more Soil Clay, loam, sand..or do you just think of it all as dirt? Without getting into the technical issues of what constitutes what, let’s just say it like this. Clay packs up hard like cement, is often gray or a rusty red in our areas, is very hard to get a shovel into and if it can accept water, generally holds it for a long period. Sand is larger particles that stay loose, water runs right through it and unless you live directly in one of the desert areas or in an old gravel pit, you likely will not have a pure sand base. Loam, well, it’s the perfect middle ground, often full of organics and a little sand and a little clay and has the consistency of good potting soil you’d buy at your nursery or garden center. Unless you live on old farm land, you likely do not have this either. The good news is, all soil can be improved, whether by amendments or cultivation techniques or combinations of both. The point here is really what to do with any of these soil types as far as water is concerned. Let’s start with clay. As I said above, it’s outstanding at holding water for long periods, as long as you can get the water into it in the first place. On really tough, compacted soils, you can do this through aeration, as I covered elsewhere in this series. If you do have clay and you’ve been able to open it up, you will need to water even less than others with different soil types, but may have to break your watering into cycles in a single night ( short runs, followed by soak in time, followed by more short runs, to “stack and push” the water in). If you have a sandy soil, you will lose your water quickly as it soaks through with not much to hold onto. Loam will generally be the baseline for water recommendations. It’s important to know your soil type so that when you do see water recommendations for your plants, you will know that you may need to go lighter or heavier, based on the soil type you have and it’s water holding capacity.

Insects & Disease So how does watering affect insects & disease issues on your plant material? Many fungal diseases are caused in our state by leaf surface staying wet as he heat comes on, creating high humidity like you might see in an unvented bathroom after a long, hot shower. Just as that’s a trigger for mildew around your tub, it becomes a trigger for a whole host of problems like powdery mildew, rust, leaf spot etc. on your plants. It also can become prime habitat for many insects that can cause trouble for you or your plants. We generally have very low humidity in our state and because of this, we do not naturally have nearly as many issues with fungal diseases as gardeners elsewhere. When we do, 95% of the time, it’s due to our own actions and therefore remedied by changes we can make. Plants drink by the root, not the leaf, watering appropriately allows for many of our pest and fungal problems to be greatly reduced, often eliminating the need for pesticides in our landscape.

Hopefully, this will give you some basic ideas on proper watering whens, whys and hows. There is a plethora of information on specific for your area and turf type run times available from local water resources like the Jordan & Central Water Conservancy Districts, SlowtheFlow.org, USU extension services and many more. A little homework now can reap rewards for a lifetime, both in plant health and water ($) savings.