When to Sow Grass Seed

A common gardening question is ‘when can I sow grass seed’? The answer may surprise you.

Whether you are wanting to repair bare patches in your lawn with LawnPro Smart Patch Mix, over-sow your lawn to thicken it up with LawnPro Lawn Thickener, or sow new lawn with LawnPro Smart Seed, there is a question about when it can be done. The answer is it can be done any time of year; so long as you are prepared to look after your new lawn grass.

The best times of the year to sow grass seed is generally regarded as spring and autumn; when the soil temperature is not too cold and the soil moisture levels are not too low. But lawn seed can be grown in winter and summer as well, you just run a bit more risk of poor germination due to a cold snap in winter or a drought in summer.

Winter Sowing

Many gardeners in the north of New Zealand do sow in winter, but ideally the ground temperature should be at least 6°C. Our fridges are usually set for 5°C for a good reason - at this temperature not a lot happens in terms of growth of most living things including grass.

The two things that grass seeds need to germinate are warmth and moisture. Moisture is not usually a problem in winter and soil temperatures on the surface can warm up remarkably quickly with a bit of sunshine, even in the south.

The risk is that if young seeds start to grow and extreme cold hits, the water in the cells of the young seedlings can freeze and rupture the young cells.

If you have sown a small area, and cold temperatures are forecast, you may be able to protect the area by laying something like a bit of fleece or windbreak over the area to protect the young grass.

Spring Sowing

Spring is usually regarded as one of the best times to sow grass seed, as the soil is moist and the soil temperature will have risen. But a sudden dry snap after sowing grass and the grass has started to germinate (which is often not easy to see), and the vulnerable young plants can shrivel up and die. So it is important to keep the soil moist in dry spells. The use of AquaGel coated seed such as that in Kiwicare LawnPro Smart Seed helps reduce the stress on seed in such dry spells.

Warm-season grasses are best planted in late spring. At that time, the weather is still mild enough to let you get the grass established, but the hot weather of summer and the most vigorous growth are just around the corner.

Summer Sowing

Sowing lawn grass seed in summer is frowned upon by many, but so long as care is taken to ensure the soil is kept moist deep down, there should be good germination and growth. A mistake, often made regarding watering, is to wet the surface of the lawn frequently. Water on the surface evaporates off quickly in summer and does not penetrate to the roots of the grass. Water on the surface also encourages roots to stay near the surface, where they are more vulnerable to drying out. It is best to water thoroughly, but less frequently, so the water has time to percolate down deep into the soil where it does not evaporate away and this deep moisture encourages the grass roots to go deep and are consequently less vulnerable to drought.

Autumn Sowing

Cool-season grasses are best sown in late summer and early autumn. At that time of year, the ground is still warm enough for quick germination, and the young grass plants have the entire upcoming cool season to become established.

Love Your Lawn

By David Brittain
Kiwicare