Stress effects of shade turf

  Shaded lawns are subject to more stress than lawns that are grown in full sunlight. Reduced sunlight can be caused by the shading effect of trees, shrubs and buildings. Fallen leaves can also shade a lawn and prevent sunlight reaching the grass blades. The fi rst stress is a result of too little sunlight. This means that the amount of photosynthesis that takes place in the grass is greatly reduced. Photosynthesis uses  the energy from sunlight to produce ‘food’ for the grass so that it can grow. The rate of growth in  shaded lawns is therefore slower when compared to sunny aspect lawns.

A side-effect of a lack of sunlight is that it results in the lawn being more subject to moss infestation as the turf is damper due to the lack of the sun’s drying effect.


The other main stresses on the lawn are caused by the roots of trees and shrubs which overhang the lawn. The roots of these trees and shrubs compete with the grass for both water and nutrients. Large trees can  lose hundreds of litres of water a day by evaporation through their leaves. They replace this water by drawing it up from the soil and through their roots. The trees’ root system can deprive grass roots from being able to take up suffi cient water. Trees can also prevent rain from reaching the lawn and soil as it can be intercepted by their leaves and branches and then lost through evaporation. Trees and shrubs also take up nutrients
from the soil and so the lawn suffers because there are fewer nutrients that are available to the grass roots. All lawns need some degree of sunlight for suffi cient growth and if this level of sunlight is not available then the lawn will not grow properly and it will be impossible to establish / maintain the lawn. If this is the case then an alternative ground cover plant should be considered along with other alternatives such as bark  mulch, synthetic turf and gravel.


Some measurements to reduce shade effects are:

  • Overseeding
  • Choose suitable grass mixtures containing tufted hair grass, red or hard fescues (see Barenbrug mixtures)
  • Water thoroughly (roughly once a week in the hottest parts of the year)
  • Mow higher than lawns that receive full sunshine
  • Only remove 1/3 of the grass