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Spring Lawn Care

Original article by David Chalmers, former South Dakota State University (SDSU) Extension Turfgrass Associate. Updated by Brett Owens, SDSU Instructor of Horticulture and Extension Associate and Kristine Lang, SDSU Assistant Professor and Extension Specialist in Consumer Horticulture.

The nights are still a bit chilly, but the sun is making up for that by giving us warm, shiny days. That must mean only one thing. It’s spring! And it is time to start thinking about that beautiful green carpet outside your window.


Gas-powered lawn aerator on lawn.

One of the first major steps in preparing your lawn for the new season is to help break up some of the inevitable compaction caused by the winter season. The weight of the snow, freezing and thawing and even those trots across the lawn to enjoy a nice mid-winter barbeque, all of these activities have an impact on crushing that precious layer of topsoil where your turf grass lives. Deciding when to aerate in the spring will depend a great deal on the climate and where you live. Be sure the top six-to-eight inches of topsoil are not frozen. It is best to use those hollow core tines (between two-to-three inches in depth), which will pull that core from the soil. Yes, your lawn will look like it just hosted an annual convention of geese, but that is short-term, as those cores will quickly break apart.

Fertilizer and Weed Control

You will find that just about every nursery, hardware store and big-box operation will have a huge selection of lawn food and weed prevention products this time of year. It can certainly be a bit overwhelming with the sheer number of options, but a lot of that tension can be eased by just doing a bit of homework before you head to the stores. Take a good inventory of your yard. Do you see obvious bare spots? Are unwanted spring weeds starting to pop up? How big is your yard? It is a good idea to take pictures, and don’t be afraid to show the salesperson when you head to the store. Keep in mind, the specialty shops (nurseries, seed and feed dealers, etc.) will most often have more knowledgeable staff. And remember the adage “you get what you pay for!”

Early-Spring Fertilizer

There are many different types of lawn fertilizer available, but the three primary types are granular, liquid and slow release. Selecting the appropriate fertilizer may seem overwhelming, but focus on the volume of nitrogen available in the product and take the time to read the label.

The fertilizer label will list nitrogen, phosphate and potash as three numbers separated by dashes (such as 10-4-3), and this represents the percentage, by weight, of each nutrient contained in the fertilizer. Most fertilizer products will tell you on the label how much to apply, and residential lawn products are often sold on a square-foot of turf stand basis (usually in units of 1,000 square feet).

For those that have applied a pretty good fall fertilization, you should plan to apply three-quarters and one pound of actual nitrogen per 1,000 square feet the following spring. If a fall fertilization program was not utilized, the first spring feed becomes even more important.

Cool-season grasses in our area like to come out of the gate quick in the spring. Their supply of carbohydrates built during dormancy helps the plants grow fast, so give that lush green carpet a mow or two before treating it to that tasty first feeding.

You should also be concerned with phosphorus and potassium levels in the spring, and the best way to understand how much of these two elements should be added to your lawn is by collecting a soil sample. It will save you time and money to use a soil sample for accurate recommendations on fertility inputs for your lawn.

Weed Control

Crabgrass Issues

If you wake up one morning and notice some crabgrass starting to sprout, you are not alone. Crabgrass is like that one pesky cockroach that somehow finds something to eat, and you have a heck of a time getting rid of. It is too easy to rush out and find any type of weed killing product, but again, knowledge and due diligence are the key. If you had to deal with crabgrass last year, you can bet it is going to show up this year. It is best to pre-treat for crabgrass using a good pre-emergent, usually during that two-week period from the end of April into May. The pre-emergence product is meant to disrupt the germination of the weeds. Keep in mind, though, it will disrupt the germination of new grass seed as well, so timing is critical.

Broadleaf Weeds

Most residential broadleaf weed control products typically contain mixtures of several herbicides to provide better control across a diverse amount of weed types than products formulated with only one herbicide. Weed-and-feed granular products for broadleaf weed control (like dandelions) on established lawns need to be applied to lawns that are moist from dew or watering, so the herbicide will stick to the weed leaves and be absorbed. Foliar spray products will often give you more-consistent control than granular products for this reason. Be sure to apply spray when the windspeed is low to avoid spray drift to sensitive plants. Always read the product labels for weeds controlled, rates to apply and safety precautions. Follow all label directions when making any pesticide application and wear appropriate personal protective equipment.

Lawn Mowing

green lawnmower being tuned up

Do not wait until the first cutting to be sure that your mower is tuned up and ready for the year. If you are not comfortable doing that maintenance on your own, no worries. There are plenty of companies out there that will take care of that for you. Remember though, chances are that many other folks are thinking the same thing, so the earlier you can get that appointment scheduled, the better. Be sure those mower blades are good and sharp. This should be done at least once per year to ensure a high-quality cut, which minimizes leaf shredding and ripping from mowing with dull blades. Clean cuts present a lower chance of introducing a fungal disease into your turf.

How often should I mow?

The rule-of-thumb when it comes to mowing is to never mow more than one-third of the turf plant in one cutting. In the spring, when that grass is full of energy and growing like crazy, that may be twice a week. Cool-season grasses do not thrive in the summer heat, and their growing patterns will certainly prove that. Mowing in the summer may be reduced to once a week or maybe even once every ten days depending on growth. It is not uncommon to think your grass is dying in the heat of the summer, but please know that these cool-season grasses are merely going dormant. A healthy lawn will start to speed up growth again in the fall.

The question arises: should I bag or just leave the clippings on the grass? There really is no right or wrong answer on this question, but an alternating pattern of bagging clippings and leaving clippings is good. Our lawns can benefit from some clippings, as they help return much-needed nitrogen back into the turf stand. Those clippings do a great job of building that strong half-inch layer of thatch that lawns can use for water retention and building up that organic matter.

Some other things to think about when it comes to mowing: Only mow when the grass is dry. A freshly-cut, wet lawn can become a petri dish for disease and other issues, not to mention all that wet grass will clog your mower (Nasty!). Always clean your mower when you are done mowing. Never try to clean your machine with the engine running. Try to keep your mowing speed consistent to get the best, most-even cut. Finally, changing direction each time you mow will help ensure the grass will grow evenly week-to-week and avoid unsightly stripes of growth that happen when you always mow in the same direction.

Special thanks to SDSU Extension Master Gardeners Tim Schreiner and Stacy Dreis for serving as volunteer copy editors of this article.