June is typically a transition month from cooler wet weather to warmer and drier weather in NH and VT. While you may enjoy the warmer weather, your lawn is composed of cool season grasses and disapproves of 80 or 90 degree days. Your grass is designed to flourish in 60 or 70 degree temperatures, but set the weather to broil and you will have consequences. For instance, even a healthy green lawn with plenty of water is still susceptible to leaf scorch – a condition similar to taking a vacation in Mexico in January. The lawn has succulent leaves, full of moisture, and they may not be fully prepared for hot weather. I have seen lawns turn from a vibrant green to patches of white or tan overnight! I can hear the phrase “what happened?” echo down the street from front porch to porch.
How can such a thing be prevented? You can mow regularly with a sharp blade to 3,” not too short as to cause stress. Don’t over fertilize either because too much of a good thing is never healthy. A lawn cranked up on the golden juice of high soluble fertilizers is predisposed to stress and what we in the business call the classic “crash.” This crash is a like watching a nice sports car hit a concrete wall – most unpleasant. A lawn that is racing in terms of growth can be dangerous, especially if that same lawn runs out of soil moisture and/or hits a period of 90 degree days. This type of weather can spell all kinds of trouble for what seemed bliss for you as a homeowner. You may see all kinds of white blotching as “hot spots,” as the sunniest areas tend to dry out first and turn a dull purple or off green.
Don’t confuse this type of situation with summer diseases which may also be present. Dollar spot, brown patch, and a hoard of numerous villains await a weak, dry lawn, or one that stays wet overnight due to late watering or humidity. Drought stress or sun scald can mimic diseases like dollar spot or patch diseases during the summer. If you are in doubt, have a professional look in order to determine what course of action may be required.
When it comes to watering, anything is better than nothing when it comes to your lawn turning from green, to dull purple, to light tan, to all out brown. Drought stress, combined with hot weather, can cause a lawn to crash and brown out in mere days if left unattended. Any irrigation is better than no irrigation in the sense that once your lawn goes brown, it takes weeks to start new growth and push out new green leaves. Brown grass leaves don’t just rehydrate and turn green for the most part – they are gone and need to be replaced. Early intervention by watering can either minimize or prevent massive browning if done correctly. Most turf wants 1” of rainfall per week to continue normal activities. If you can water in the morning, this is preferred to help minimize disease and evaporation in the day’s heat. Watering for a soaking is better than a light misting. In other words, a 1hr soak is better than 15 minutes a day, yet 15 minutes a day is better than no irrigation at all. Early watering will yield faster results and help the lawn stay green before things turn tan or brown. Watch for those hazing dull patches, those sections that don’t bounce back after you walk over them so you can still see your footprints. These are the priority areas that need water versus turf that is still a vibrant green.