Grass seed germinates at different rates, depending on various factors such as the grass species, weather, time of year and soil moisture. Typically, germination takes between five and 10 days. Once germinated, the grass will continue to grow at a rate of about 2/3cm per week.
We list some of the variables of grass seed germination below, plus tips on how to ensure successful, even germination, so you can grow the perfect lawn.
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Time of year
The time of year is a huge factor in the germination rate of grass seed. Cold air and soil temperatures prevent germination, so avoid sowing grass seed in winter as it simply won’t germinate. A cold spring can delay the germination of grass seed by up to a few weeks, leaving the seed vulnerable to being blown away or eaten by birds, while a hot summer can also inhibit growth, particularly as warm conditions dry out the soil. Soil temperature should be at least 8 degrees Cº or for successful germination. Bear in mind that seed sown in the south of the UK will germinate sooner than that sown in the north of Scotland. Generally, we recommend sowing grass seed in mid-late spring and again in early autumn.
Moisture of the soil
Grass seed germinates well in moist soil that’s not too wet or dry. Keep the soil moist to aid germination, but ensure you use a fine rose or spray to stop puddles forming on the soil that may inhibit germination or wash the seeds away.
Different seed mixtures germinate at different rates. As a general rule, hardwearing seed mixtures, usually containing ryegrass and red fescue, germinate after just four days. Other seeds, particularly bent and meadow grasses, can take up to two weeks to grow.
Tips for success
- Keep the soil moist at all times but don’t over-water
- Sow seed in spring or autumn when soil temperature is at least 8Cº
- Don’t allow the soil to dry out until there is a dense matt of green growth growing where you sowed the seed
- Use a high-quality seed mix and follow the instructions on the packet as to how densely to sow the seed
- Avoid sowing on a windy day as this can blow grass seed about