I know the feeling – you have worked on your lawn to make it look green and verdant, trimming, watering, and feeding it. Then it selfishly turns its back on you and starts producing puzzling little brown patches that grow and spread until the lawn you worked so tirelessly for resembles a distressed soccer field. There could be many reasons for these dead-looking patches, so read on.

This could be a fungus that spreads across grass leaves, leaving dead spots on the infested areas. Most fungi stay dormant in wait for the perfect conditions for growth and reproduction. The brown or dead spots will start to show during the warmth of the hot summer days and the moisture from the nighttime irrigation you are doing. It first appears as irregular patches of weakened grass that may enlarge to many feet in diameter, and fungal threads may be apparent. With time, fungal residue inhibits photosynthesis, as the fungi gradually spread across the grass leaves, leaving dead spots on the infested areas. The visual results are patches of brown grass.

Compaction could be another cause - dead grass patches in lawns may also appear if the ground beneath your turf is compacted. This is especially common for newly-sodded lawns, whereby homeowners usually overlook the importance of ploughing, aerating, and dethatching the lawn. Such compact soil causes drainage issues during watering or rainfalls, with the resultant waterlogging causing root suffocation.

Heavily shaded areas in your lawn are also highly susceptible to dead grass spots, and Bermuda grass in particular requires sufficient sunlight for photosynthesis. Too much shade exposes this grass variety to pests and diseases. If you’ve got trees and other flora in your lawn, they may be cutting off the supply of sunlight to your grass. Most grasses require at least 4 hours of direct sunlight each day. Less than this amount of sunlight exposure causes the grass to photosynthesize less, thus reduces the amount of energy available to the plant and retards growth. In turn, grass will suffer reduced tolerance to heat, cold, drought and disease.

Grasses have the ability to go dormant for differing lengths of time depending on their genetics and overall health. Most established lawns can stay in a drought-dormant state for 3-4 weeks without dying. During dormancy, your grass is conserving its energy and water and sending its resources down to the root system rather than to the grass blade itself. This will cause your grass to turn brown and appear to be dead but, inside, the grass crown remains alive. This is a normal condition; your grass will recover when the temperature drops and rain resumes.

Round brown patches might indicate animals are peeing on your lawn. The urine of pets contains high levels of nitrogen, and nitrogen overdosage can kill the grass. If your pet has a favourite spot, flush the area with water to dilute the acid.

Your mower blade is maybe too dull, which can lead to ripped and torn grass with frayed ends. Dull blades will tear and bruise the grass giving the lawn a brownish tint.

Too much water, not enough water, overmowing, grubs eating the roots – all causes for browning! Mowing the grass too frequently, too short, and leaving clumps can create a brown lawn or brown patches in your lawn. Make sure you are cutting the grass a proper amount for each season, only cutting a third of the length of the grass and removing grass clumps from the lawn after mowing.

If it is a fungus causing all this damage, apparently there are ones you can use that are safe to use around pets and children, but follow the product advice on the label, which very often means keeping them inside when you are spraying and until the product has dried. When shopping for a natural lawn and garden product, be sure to read the label carefully. Just because something includes the word ‘natural’ on the packaging doesn’t necessarily mean it is. If you’re in any doubt, visit the manufacturer’s website for more information, or contact them for details of the ingredients they use in their products.


Marilyn writes regularly for The Portugal News, and has lived in the Algarve for some years. A dog-lover, she has lived in Ireland, UK, Bermuda and the Isle of Man. 

Marilyn Sheridan