Why do it?
Overseeding will thicken up a lawn and help stop an evasion of weeds into the lawn it an effective method to rejuvenate your lawn.
Overseeding is spreading new grass seed to your existing lawn which replenishes the old grass and fills in bare patches.
There may be areas that are adversely affected by shade or perhaps the lawn has become worn from kids playing on it, it may have suffered an infestation of moss.
Overseeding can also help make your lawn more resistance to diseases.
The best times to over seed?
Spring through to autumn are the best times to overseed.
We recommend that it is done after heavy scarification or aeration, either in the Spring or autumn as generally it is warm and wet.
If it has been a dry summer and the grass has been adversely affected or worn or looks tired caused by drought conditions. September in an ideal month to overseed and fix the lawn as the conditions are usually warm and wet.
Factors needed to grow grass seed
To grow grass seed there are two main factors soil temperature and moisture.
Grass seed needs soil temperatures to be at least 6-8 degrees Celsius (dependant on cultivar), and frequent rainfall is important to ensure the seed germinates, if there is no rain present we strongly recommend watering your lawn if you have over seeded it recently. For more information on how to water your lawn see here
If your lawn has been over seeded in the late Spring or Summer you may need to keep the lawn watered with a sprinkler system to provide adequate soil moisture level to achieve a good rate of germination.
It is possible to over seed in winter – There are specialist seeds that will germinate in the winter, however it is recommended that for the average lawn it is better to wait until the soil and ambient temperatures heat up. The specialist seeds are best kept for large landscaping projects or sports applications such as football or rugby pitches.
How to overseed
Throwing down grass seed without any preparation is usually a waste of time and money as there will not be enough protection for the new seedling to survive and the ground will be to compacted for the new seeds to germinate in or the seed may not be able to compete with the thatch layer that is in the soil.
Premier Lawns recommend that it is best done after scarification as it bypasses any thatch and or organic matter present.
Scarification creates lines in the turf that is perfect for seed to germinate in. The lines created after scarification provide the new seedlings with a safer environment to grow.
It provides protection from the elements and creates somewhere safe for the seed to geminate and grow.
It is usually best to feed the lawn when applying grass seed as it provides the new seed with the correct nutrients.
How long does it take the seed to grow
Seedbed preparation is key to survival of the new seedlings, overseeding into a warm, moist, seedbed and ensuring that the seed has good contact with the soil, help ensure a rapid germination, development and growth of the new seedlings.
If the correct levels of temperature, nutrients and moisture are present, seed will generally germinate in up to fourteen days. Different varieties are faster than others and different soil temperatures will also affect germination rates.
Generally hardwearing seeds such as Perennial Rye-grass (Lolium) will germinate faster; in seven to ten days and require soil temperatures 6 degrees Celsius and above.
Finer grasses such as Fescue (Festuca) and Bent (Agrostis) will take longer at least ten to fourteen days and require at least 10 degrees Celsius to germinate.
Hard wearing, winter hardy and drought tolerant grass such as Smooth Stalked Meadow-Grass (Poa pratensis) can be hard to establish and is best left until late Spring or September as it requires higher soil temperatures.
However if your grass seed was sown in early Spring it may take longer as the soil temperature may be to low to allow germination, in most cases the seed will still germinate if the seedbed was established through scarification in early spring.
Aftercare
It is best to maintain moisture levels – if no rain is present, the lawn will require watering on a daily basis for at least four weeks, six weeks for optimum results.
When mowing the lawn, it is usually better to raise the height of cut on your mower as this will allow the new seed to grow.
Quick facts
Overseeding thickens up for lawn
Better resistance to weeds, moss and disease.
Overseeding is best done after scarification or aeration in the spring or autumn
Hardwearing grass – Perennial Rye-grass
Fine lawns – Fescue and bent grass
Drought tolerant – Smooth Stalked Meadow-Grass
Shady areas – Fescue grass
Water daily if no rain is present for six weeks to aid germination and survival of seeds