You may have noticed the wet weather in recent weeks has had a detrimental effect on the lawn and could have removed a lot of nutrients leaving the lawn looking yellow and impoverished, this can happen especially if you removed the clippings from the lawn or perhaps your lawn is appearing lush in appearance following applications of fertiliser resulting in soft excessive growth. We are beginning to see some lichen, algae and liverwort appearing in areas of the lawns along with a common disease at this time known as red thread or pink patch.

This disease is quite distinct in its appearance and lives up to its name as it turns the leaf of the grass plant red or pink in appearance, closer examination shows an almost cotton wool or candy floss like appearance on the grass leaf. This particular disease does not normally cause too much damage but can give an unhealthy looking appearance to the lawn.

It is an indicator of low nitrogen level within the plant therefore a small application of fertiliser either applied as a granule or liquid will help to eradicate the disease and improve the overall appearance and condition of the lawn.

It is worth remembering not to apply too much fertiliser in the current weather conditions and perhaps keep nitrogen low in the fertiliser you apply, perhaps to 4 or 5%, this is shown on the bags purchased in garden centres for example a 4-0-8 indicates 4% nitrogen.

Another problem noticeable in the last week has been the appearance of lichen, algae and liverwort. The fluctuating temperatures combined with rainfall have given the perfect environmental conditions for this type of lawn problem to appear. These particular patches colonise and can make the lawn very slippy to walk on and reduce the grass on the lawn allowing for further infestation from weeds and moss.

Algae appears as a black slime on the lawn with lichen giving a scale like appearance and liverwort gives an almost small leaf like look to its appearance. All three can be treated in the same way. It is common for this type of lawn problem to appear under shade or in compacted areas. A good way to control lichen, algae or liverworts is to aerate the area with garden fork or a more effortless way is to wear spike overshoes and simply walk over the garden allowing the spikes to make many small aeration holes in the lawn, by introducing air through the affected area this reduces compaction and the introduction of air through the algae or lichen stops its ability to continue and spread.

Applications of sand also assist in reducing the algae, lichen or liverwort, applying the sand following aeration AIDS drainage in the lawn. A fertiliser such as lawn sand will have low nitrogen but will contain ferrous sulphate and this has an effect on algae, lichen and liverwort as well as any moss that may have spread during this wet period. It is a good idea to keep as much aeration in the lawn as possible throughout the year as this gives channels for grass roots to grow allowing a healthier, stronger lawn.

Paul Brannan