Welcome First name / fellow lawn addict to another instalment of “The Fulcrum”.
Today it’s time to jog our memories on how to look after our cool season grasses during the warmer months. This is a time of careful management and record keeping, so that we can make sure were not going to cause further issues. Careful water management in the heat, and input management are key. Although this specific time of year is the sweet spot for all of us, we need to ensure that we are getting the most out of this weather and push as much growth and strength as we can. This is needed so we can train and help our grass be more resistant to stressors.
Heat Management & Watering
Cool-season grasses like fescue, bluegrass, and rye struggle when temperatures rise above 28°C. To minimize heat stress, you should water regularly, applying at least 15mm three times a week as a baseline ideally in the morning. On days when temperatures exceed 28°C, you can add up to an additional 5mm per day, to cool off the turf, this is a practice known as Syringing. This needs to be done mid afternoon, avoiding the hottest part of the day and still leaving enough time for the turf to dry before night and especially not after mowing. This will prevent the grass canopy from becoming too warm and humid, which can encourage the growth of fungal diseases.
Watering early in the morning is crucial for three reasons:
Disease Prevention: Late watering can create a damp environment that promotes fungal disease in the grass.
Avoid Overheating: Water is an excellent heat conductor, so watering in the middle of a hot day can trap heat around the grass blades, essentially "boiling" them.
Limiting Evaporation: when watering during the cooler part of the day, there is less heat to take the water away from our grass. and with cool season grasses, every little bit counts.
Fertiliser. DO LESS!… I know what you're going to say... I can hear the cries of, "but if we don’t fertilise our grass won’t grow". I’m not saying don’t fertilise, more of a caution to not use too much.
Fertilisers are already tested and formulated to be applied at the optimal rates (on the label). I know a lot of you will be thinking, if some is good, surely more is better. In this situation certainly not, as growing too fast can be detrimental to the grass. If we are not extra careful, and putting down too much nitrogen, with the heat and humidity, we can create an environment ideal for growing disease and fungi. And like our warm season grasses cool season grasses almost go dormant during the summer as temperatures are too high for them to grow.
Soil amendments. Remember these things? Yes, they’re back. Regularly timed applications of amendments will make it easier to look after the cool season grasses. This can help us manage soil moisture and increase nutrient availability. Spot treatment of “hotspots” or dry patches rather than the whole lawn can be done using a watering can (yes you read that right) with a dash Hydrolink will help alleviate dryness.
Mowing. As usual, regular mowing is one of the best tools we have to maintaining an even grass surface. This is no exception with cool season grasses. As mentioned they will slow down during the warmer months which will reduce our frequency. However attempting to maintain 1-2 mows per week will be ideal, but this depends on growth. We don't want to go much lower (if at all) than 20-25mm.
