‘Weed’ grasses are vigorous, undesirable and difficult to remove your lawn all together. All lawns can suffer from coarse grasses establishing. This can be down to several reasons, wind carrying seeds, birds etc…
There are no selective weed killers that can be used against coarse grasses in lawns without also killing the more desirable turf grasses also. This very much limits the removal of coarse grasses to ‘cultural’ methods only (i.e digging them out!).
Prevention is far more important than curative methods as once the coarse grasses have established the most effective method of removal is by hand. This can be done with a fork, preferably in the Autumn or early Spring which should also coincide with the application of top soil and a good mix of grass seed. If coarse grasses are present and abundant across a larger lawn area then control is extremely difficult. This is why prevention is crucial…
Undergoing routine selected lawn feed treatments throughout the year will boost desirable lawn grasses. Mowing regularly is effective as finer grasses are much better adapted to being cut whereas most coarser grasses can be significantly weakened after a weekly trim. Raking the lawn lightly with a spring tine rake before mowing will help to lift any lateral growth coarse grasses.
As a final method of control; if infestation is beyond cultural repair or renovation then acidifying the lawn is an option. Coarse grasses, particularly Poa Annua, will not survive if present in very acidic soil. Do not apply lime or lime-based products to the lawn as this will reduce the acidity of the soil and will create an alkaline medium promoting coarse grass growth. Gradually reducing the ph can help however this method is really not advised!
Above all else, a thick healthy lawn will act as a barrier against invasive coarse grasses. This really is the key!
For more advice regarding those pesky weed grasses just ask Joe!