In the current era of stay at home orders, only go out for essential services, avoid crowds, etc. many homeowners are in a quandary, given they have more time around home, of what they should or shouldn´t be doing for their lawns. “Do I go to the hardware store to buy fertilizer, crabgrass control and weed killer, or is that considered essential? And what happens if I don´t apply any of these products?”
Let´s start by pointing out that your lawn will survive almost anything you do or don´t do short of spraying it all with glyphosate (which will kill it!) If you apply absolutely no fertilizer this spring, no crabgrass preventer, no weed killer, you will still have grass. It may not be quite as green. It may have a few more dandelions and a few more unwanted annual grasses (like crabgrass or foxtail), but the grass will survive. There are several things that you can do, regardless of what you did or didn´t get done, that will help improve your lawn.
First of all, set your mower´s cutting height high. How high? How high will it go? I´m only joking a little bit with this but seriously for tall fescue and Kentucky bluegrass three (3) inches is as low as I would go and for fescue 3½ would honestly be preferable. These species have very upright leaves. The leaves are the factory where photosynthesis occurs and photosynthesis is the biochemical process that takes sunlight, water and nutrients and turns them into food for the plants. You need a longer leaf blade to have enough “engine” available to keep the plant healthy, alive and growing. Longer leaf blades also shade open spots in the turfgrass stand. If sunlight can´t get to the ground then many of the weed seeds that are there won´t sprout and grow and be a problem.
When deciding when to mow you should follow the 1/3 rule. Never cut off more than 1/3 the total height of your grass. If you are cutting your grass at a 3 inch height don´t let it get taller than 4½ inches before you mow. You can mow more often if you want. The key here is regular mowing. As grass leaves get longer they produce more food and the plant produces more roots. If you let the grass get real tall and then mow it short, it shocks the plant and roots that were produced when the grass blades were long, will die. This all or nothing approach is hard on the plant. Mow regularly and it doesn´t get shocked.
Secondly, stop bagging your clippings. If you are mowing regularly, as I just described, and most of you probably can right now, the clippings aren´t going to create a thatch problem. Grass leaves are mostly water. If you are cutting regularly and don´t bag the clippings they will filter down to the soil level and break down fairly quickly. If you are leaving windrows of mowed grass then you are not mowing often enough! A little thatch layer in your lawn isn´t a problem, in fact it´s a good thing. It doesn´t become a problem until it is 3/4 of an inch thick or more and that rarely happens!
Crabgrass is going to start sprouting soon. If you are late getting your crabgrass preventer applied, that´s okay, apply it when you can. There are some very effective crabgrass killers that you can spray over the top later on to control that small crabgrass and the preventer will reduce how much crabgrass germinates later. More importantly, follow proper mowing procedures and then this fall, make sure to fertilize in early September and then fertilize again and apply broadleaf weed killer in mid to late October. Your turf grasses will survive all of this just fine as long as you don´t do anything too crazy!!
CHUCK OTTE is the agricultural and natural resources agent with the Geary County Extension Office.