Heat Stress in lawns
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Heat Stress in lawns

Given the hot weather we are experiencing it seemed fitting to put together some advice on heat stress in turf to help you better manage your lawn through the summer.

When turf becomes stressed or any plant for that matter it begins to shed its leaves particularly in drought conditions to conserve moisture. So its important to help your plants store and conserve moisture.

Plants in this case turf plants breath via the stomata small openings on the underside of the leaf. They open and close usually at night to release gases produced in photosynthesis. During the daytime the stomata are usually closed to conserve moisture. Plants require potassium to control the opening and closing of the stomata so its always good to ensure at least one of your feeds tops up your potassium levels.

To better help a lawn through the summer its really important to ensure that the spring and summer treatment is carried out correctly and on time to increase root development and prepare the plants before the hot weather appears. It is within the roots that nutrients can be stored so increasing root development by feeding and aeration to promote deeper rooting should be your priority before hot summers. You may also want to check your PH in spring and top up calcium levels. As calcium will create stronger vascular systems in the plants themselves meaning water and nutrients can move more freely.


Plants when stressed will begin to wilt once this happens they shut down as the cells collapse into a a state of plasmolysis. In some cases they are irreparable and it leads to a brown lawn. However as long as the roots do not bake and are deeply established the soft growth tissue of the leaf blade will regenerate. Though at a cost if the ground bakes too hard and gasses build up and increase the soil temperature not only the roots can perish but so can the beneficial fungi and bacteria that aid nitrification and amino acid production.

Energy stored within the root will be consumed when the plant tries to regenerate and once consumed those areas of the root may then die as reserves are depleted. Its usually at this time the plants become most vulnerable to pest and diseases most commonly red thread. So in order for the lawn to regenerate it must use up its resources and some of its root system which we have worked so hard to establish. When we water the lawn it creates what is know as a soil solution. The soil solution is exactly what it means a solution made from the elements within the soil which can be mineral, salt, macro, micro nutrients and trace elements.

When we water or irrigate it is predominantly the roots that absorb the soil solution unless we water late evening or at night when the stomata open. It is imperative to ensure the root system has air space to grow within along with a rootzone that is capable of retaining adequate amounts of moisture and soil solution. Firstly to avoid leaching and loss of nutrients but also to enable the plants a supply of water. If a lawns struggling spiking is usually the only option in summer if the ground is hard. In some cases the application of a wetting agent to open up the surface of the soil so water penetrates into the rootzone  can be beneficial and if found to be struggling can be aided with a sifted compost top dressing.

Stressed turf

Stress such as high temperatures, low humidity, high traffic, wear, etc. all have an effect on the turf plant metabolism, which results in a decrease in the quality of the turf, and an overall decline in turf health. By applying amino acids before, during and after these stress conditions, turf amino acids which are directly related to anti-stress have a role in prevention and recovery from stressful conditions. If we are experiencing very hot summers in some cases its best not to feed at all or just with organic bio feeds such as seaweed. It is most often when turf becomes stressed that disease comes to the forefront.


Plants synthesize carbohydrates by photosynthesis, low photosynthesis results in slow or no growth. Again if plants are struggling to photosynthesis due to damage elements can be absorbed via the stomata to allow the plant synthesis. Which again is why liquid feeds applied early morning or late evening will be best for stressed turf.

Summer tips

So what can you do to help your lawn in the summer heat? Increase the mowing height up to 4 inches if necessary to conserve moisture cutting grass short simply adds stress. Keep the mower blade as sharpe as you can to enable a clean cut. Try mowing either early morning or late evening in the coolest parts of the day. Consider spiking and compost top dressing the lawns. Lastly you can look at irrigation most lawns require at least 1 inch of water per week. You can water in the hottest part of the day it will not damage the lawn but you will loose water to evaporation. So its best to water at cooler times of the day deep infrequent watering early morning allows moisture to be efficiently absorbed by the root system.

Cost vs Quality

You really get what you pay for with a lawn treatment. If your lawns tired and your considering lawn care give us a call and see what our  program can do for you.


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