Bob Mann

Expert Q&A

My water bill is out of control. Is there anything that I can do to reduce the amount of water that I am using in my landscape, or should I just start ripping things out?

A: It’s just human nature – if you spend many thousands of dollars to have an underground irrigation system installed to water your landscape, you think it should be used every day. The fact of the matter is that most people irrigate far too often and when they do irrigate they apply too much water. Plants have been around a lot longer than irrigation systems so they know what to do when things get a little dry. The United States is a very big place with many wildly different climates so we can’t give specific advice that will match everyone but consider backing off a little bit at a time to see if there’s room for water savings.

I use an irrigation system to water my lawn and ornamentals. Now that the service technician has opened the system for the season, I should be all set, right?

A: An irrigation system should be thought of as a machine that does work, and because of that it is going to break from time to time. The problem is that most of the system is underground and out of sight. A good practice is to operate the system manually once per week (after mowing is a great time) and observe the system running. One or two minutes per zone will be sufficient to make sure that each sprinkler head is operating correctly. See that the head is spinning around as it should, that the water is unimpeded by surrounding plants and that it is not leaking. Sprinkler heads should also not apply water to impervious surfaces like your driveway or the street. Adjust the heads as necessary to remedy.

I was listening to a gardening talk show on the radio and the discussion turned to soil testing. Why is soil testing important, especially for saving water?

A: A soil test is analogous to the blood tests that your doctor orders for you. It gives a snapshot of what’s going on and points out problems that affect your lawn and ornamental plants. The first thing that is measured is the soil pH, or how acid or acidic the soil is. Think of soil pH as being the door to your refrigerator. If the measurement is less than optimum, the plants will not be able to access nutrients in the soil, much like trying to get food out of your refrigerator if the door is blocked. A soil test will also measure levels of many different nutrients your plants need to grow, too. An enhanced soil test will measure physical characteristics of your soil, for instance how much sand, silt and clay it contains and how much organic material is present. Getting soil chemistry right is fundamental to gardening success. If you have questions, reach out to an NALP landscape professional for help.

I hear people talking about something called “soil health”. What is it and should I be concerned?

A: Plants are a lot tougher than we give them credit for – certainly you’ve seen crabgrass growing though a crack in an asphalt driveway in the middle of the summer, right? The sad truth of the matter is that in the building industry making the kitchens and bathrooms bright and shiny is important. Installing quality topsoil for the landscape is not. You would not believe the things that professional landscapers find buried in their customer’s soil. The good news is that plants can and do create their own habitat. The longer plants occupy a site the more organic matter will build up in the soil.

When buying topsoil, try to find a source that has sufficient organic matter (the stuff that makes the soil black), will drain readily but also hold sufficient water (the correct balance of sand/silt/clay) and has decent soil structure. What’s that? Soil particles that cling to one another forming larger clumps. Perhaps you threw “dirt bomb” at each other when you were kids, that’s what I mean.

I was watching the golf tournament on television on Sunday. The course looked amazing. I want my lawn to look like that. How do I do it?

A: Take it from someone who worked on golf courses for a long time – don’t do it. What you see on Sunday afternoon is the culmination of years (yes, years) of preparation so that the course would look perfect for that specific moment. The amount of money, time and resources it takes to achieve perfection is completely out of reach for the average homeowner. The funny thing is that homeowners want to cut their grass short so that it looks like a golf course, while a golf course superintendent wants to let the grass grow taller so that it’s healthier. There’s a lesson in there somewhere.

My old lawnmower is on its last legs. What kind I should buy to replace it?

A: This is a great opportunity to up your lawn care game. So many of the problems that we see on customer’s lawns are actually caused by the customer’s poor mowing habits (sorry for the tough love there). Residential lawns need to be cut much taller than what the conventional wisdom currently dictates. Each species of grass has its own optimum height of cut and most lawns are a mixture of different species but a general rule of thumb is 2 ½” to 3” in height. If you can, cut it taller. A higher height of cut shades the soil surface, lowering soil temperature and reducing weed pressure. Frequency matters, too. Follow the one-third rule when mowing. That means that with any one mowing, do not remove more that one-third of the total height of the lawn. For instance, if the lawn is at 3” in height, do not cut below 2”. What this means for the average homeowner is that for most of the season, a single weekly mowing is sufficient. OK, that’s a long way around to get to talking about lawnmowers, isn’t it? Consider purchasing a mulching mower, one that finely chops up the clippings and redeposits them on the lawn surface. Why? Yard waste is a big problem in the total waste stream and when you throw away clippings you’re also throwing away money and the prospect for soil health. Contrary to what you may have been told, grass clippings do not cause thatch to build up (thatch is a layer of intermingled living and dead plant tissue that exists above the soil surface but below the verdure (the green part) of the lawn). Thatch is the result of slow decomposition of plant tissue that contains significant quantities of lignin – the stuff that makes roots and shoots stout. Grass clippings have little lignin and decompose quickly. What’s also true about clippings is that they’re full of nutrients (fertilizer) that can be readily recycled