If Necessary, Kill the Existing Lawn
If you have been struggling with weeds it is important to effectively kill all the weeds to the roots so that they don’t come up again in your new lawn.
Spray the whole lawn with Kiwicare Weed Weapon Extra Strength or McGregor’s Weed Out. These systemic herbicides will kill the lawn grass and weeds (including coarse grass weeds) to the roots. Wait 3 weeks for the full death and if any new weeds appear or re-sprouting occurs, re-apply. You can sow seed within a week of spraying.
Remove the Dead Weeds and Prepare the Soil
Using a scarifying rake or strong braced garden rake, rake out the weeds and dead grass from your lawn.
Now there are some things you need to do the check the soil and make improvements:
- Check the pH of the soil and adjust it with lime (raises pH) or sulphur (lowers pH) to get a soil of between pH 6.0 and 7.0
- Check the soil type. Most soils are mixtures of all three particle sizes but in varying proportions. A predominance of sand particles makes a lighter, more open soil with good drainage and aeration. Minute clay particles pack together tightly making a clay soil heavier, denser, and with less favourable air and water penetration. If you have a heavy clay soil add sand or use gypsum to help break the clay up and add a 8-10 cm layer of well-draining topsoil on top.
- Check the level of your lawn. Look for hollows and dips and level these off with good topsoil using a landscaping rake. These strong wide aluminium rakes make it easy to get a good even surface.
- Note: it is ideal to have a slight slope to your lawn so the water does not pool on the surface in heavy rain. On a very flat area dome the lawn slightly in the middle so heavy rains run off to the sides.
- Use a taught string to check the level and slopes of your lawn and topsoil dressing.
Choose Your Seed
Most areas of New Zealand are suitable for a fine turf lawn. But there will be variations of sun and shade, likely wear and tear, and climate that might affect your choice of lawn seed. The Burnet’s Range of grass seeds has a variety to suit your situation, and Kiwicare Lawnpro Smart Lawn Seed is an excellent blend and has the added benefits of seed with Aqua-Gel coating to ensure germination, even if you forget to water for a day or two. It also has included fertiliser for initial germination and establishment of the grass, and is a blend of creeping red fescue and perennial ryegrass which will thrive in sun, shade and is hard wearing. For the majority of fine turf lawns, a blend of grass types give the lawn ability to tolerate sun, shade, high wear and a broad range of climate.
Water and Prepare the Lawn for Sowing
Water the lawn gently but thoroughly, so the soil is wet deep down. A light water on the surface is not enough. Then let the water drain so the soil surface is not sticky and you can walk on it without making a mess.
Tamp down or stamp down the topsoil top dressing and then rake it lightly with your landscaping rake. You want the soil to be firm but the surface to be lose.
Sow the Seed
Sow your seed at the recommended rate. Then rake the soil lightly with your landscaping rake to ensure the seed is in good contact with the soil and water lightly. The seed needs warm moist soil and light to germinate. Water gently in the mornings. It is OK for the surface to dry out so long as there is moisture underneath.
Stop Birds Eating the Seed
Although birds can overcome the aversion to repellents, they do reduce the amount of seed taken, if any. So you should also:
- Provide other food for the birds. If you give the birds alternative food such as at bird feeders, they will prefer that to the repellent seed. It is best to site the alternative food well away from the lawn.
- Use visual and sound repellent devices. Bird scare tape fluttering from canes stuck in the lawn can be enough to deter birds for the 7-10 days needed to allow the seed to germinate. Alternatives include, plastic shopping bags or old CDs/DVDs hung from the canes. Fake predators and balloons are available that will deter birds for a week or two. Wind chimes and other noise-making devices may also have a deterrent effect for long enough for germination.
- Cover the seed with fine netting that allows light and water to get to the seed but excludes birds.
Watch it Grow and When to Mow
The seed will germinate in about 7 days. Let it grow to around 5-8 cm tall before giving it its first light trim with a sharp mower. A blunt mower will damage the grass and may pull grass out that has not got fully developed roots.
Thereafter mow as needed but gradually lower the cutting height to about 3 cm, which is ideal. Do not remove more than 1/3 of the growth at any one time.
If weeds appear in your new lawn, spot treat them with LawnPro Turfclean at the young lawn rate. Only apply to whole lawns when they are at least 2 months old.
During periods with warm nights irrigate the lawn as necessary but do it in the morning so that grass blades dry during the day and are not damp through the night. This helps prevent fungal diseases.