How to water new turf and seed

New turf arrives without most of its roots. Seed has none at all. For the first few weeks, the new lawn depends entirely on you to keep it alive, and watering is the job that decides whether it knits into the soil or dries out, shrinks and dies at the edges.

Watering a new lawn is different from watering an established one. It starts with frequent watering to keep the turf or seed moist, then changes, step by step, to the deep, less frequent watering that grows deep roots. This guide covers both stages, how to check you’ve got it right, and what to do about water rules.

Before you lay or sow

Plan the watering before the turf arrives.

• Check your water rules. Many water authorities make allowances for new lawns, but you may need to apply first. In Perth, Water Corporation grants exemptions to water a new lawn outside your rostered days: up to 42 days in spring and summer and up to 35 days in autumn and winter, applied for on the day the lawn goes in. Other authorities have their own rules. The watering under restrictions guide links each city’s official page.
• Choose the season. New turf needs less water in the cooler months, as long as the grass is still growing enough to root. Laying in the heat of summer is possible, but it needs the most water and the most attention.
• Check your sprinklers. If you have an in-ground system, run each zone and fix broken or blocked heads before you lay. A dry corner on an established lawn is a nuisance; on new turf it’s a dead patch.
• Have a plan for hand watering if you don’t have sprinklers. A hose-end sprinkler on a tap timer is far more even than a hand-held hose.
• Water the soil the day before. Laying turf on dry soil means the soil pulls water out of the turf. Moist, not muddy, is ideal.

Stage 1: the first watering

Water each section as soon as it’s laid, rather than waiting until the whole lawn is down, especially on a hot or windy day. Turf can dry out within an hour or two in the sun.

Give the first watering a thorough soak: enough to wet the turf right through and the soil underneath. Then lift a corner and check. The soil under the turf should be moist. If it’s dry, water again.

Stage 2: keeping it moist while it roots

For the first week or so, the aim is to keep the turf and the soil just underneath it moist all the time. The new roots are short and can only reach the top few centimetres of soil.

Water Corporation’s advice for new turf in Perth is to water three times a day for the first week, then reduce gradually over the following weeks as the roots grow. Perth’s sandy soils and hot summers make it one of the more demanding places to establish a lawn, so in milder weather or on heavier soils you may need less. The principle is the same everywhere: little and often while there are no roots, with enough water each time to wet the soil under the turf.

How to check

• Lift a corner in a few places each day, especially near paths, edges and the sunniest spots. The soil under the turf should be moist, not dry, and not soggy.
• Look at the joins. Turf that is drying out shrinks, and the gaps between pieces widen. Water those areas more.
• Watch the colour. Turf that turns dull or bluish-grey is short of water.

Adjust for the weather

Stage 3: reducing as it roots

After about a week, start checking for rooting. Gently tug a corner of the turf. Early on it lifts easily. Once roots have grown into the soil, it resists.

When it resists, start watering less often but for longer. Each step encourages the roots to follow the water down.

A typical pattern looks like this, but let the lawn and the weather guide you:

1. Reduce from several times a day to twice a day.
2. Then to once a day, with a longer run.
3. Then to every second day.
4. Then towards the deep, less frequent watering you’d give an established lawn.

Water Corporation describes this as reducing gradually over a period of weeks. Rushing it is the most common mistake: a lawn that goes from three waterings a day to twice a week overnight will brown off in the first hot spell.

Watering seed

Seed is different, because it sits on or just under the surface.

• Keep the surface damp, not wet, until the seeds germinate and the seedlings are up. That may mean light watering several times a day in warm weather.
• Use a fine spray. A heavy spray washes seed into low spots and leaves bare patches.
• Don’t let the surface dry out. Seeds that start to germinate and then dry out die.
• Once seedlings are up, water a little longer and less often, so roots grow deeper.
• As the lawn thickens, move gradually to the deep, less frequent watering of an established lawn.

Warm-season grasses need warm soil to germinate. The bag will give the conditions and the time to expect. Check that seed is available for your grass type: some lawn grasses are usually established from turf or runners rather than seed.

Using sprinklers well

• Do a quick catch-cup test before you lay. A few straight-sided containers on the area for 15 minutes show whether the sprinklers cover it evenly. Fix any gaps first.
• Use a tap timer or controller so waterings happen even when you’re at work. Set it to your water authority’s rules or your exemption.
• Water early in the morning for the main watering, with extra waterings during the day in hot weather while the turf is new.
• Watch for run-off. If water runs off before the turf and soil are wet, use shorter cycles with a break between them.
• Move hose-end sprinklers on a set pattern so every area gets the same.

Common problems

Walking on new turf and the first mow

• Keep off as much as you can while the turf is rooting. Footprints on soft, wet turf leave dents and tear new roots.
• Mow once it has rooted and the grass has grown above your mowing height. Water Corporation suggests the first mow is usually 10 to 14 days after laying in summer and 14 to 21 days in winter.
• Mow on the highest setting first, with sharp blades, and don’t take more than a third of the leaf.
• Let the surface dry a little before mowing, so the mower doesn’t rut the lawn. Skip that day’s watering if you need to.

Feeding and chemicals

• Follow your turf supplier’s advice on when to feed. Many suggest waiting until the turf has rooted.
• Hold off on herbicides and pre-emergents until the label says the lawn is established enough. Pre-emergents can stop new turf rooting; see the pre-emergent answer.
• Use the label rate when you do feed, and water it in as directed.

When is it established?

When the turf resists a firm tug everywhere, the joins have closed, and it has been mown a couple of times, you can treat it like an established lawn. That means deep, less frequent watering based on the season, your soil and your grass. The how much water does a lawn need guide covers this. If you were granted an exemption, return to your normal watering days when it ends.

Common mistakes

• Light sprinkles that wet the leaves but not the soil underneath.
• Waiting until the whole lawn is laid before watering the first sections.
• Keeping turf soggy for weeks, which rots roots and invites disease.
• Cutting back too fast, from several waterings a day to twice a week.
• Forgetting the edges, which dry first.
• Laying turf without checking the water rules or applying for an exemption.

Log it

Log each watering in your Lawn Journal for the first few weeks, with the time and how long you ran each zone. Add a note when the turf first resists a tug and when you first mow. Next time you lay turf or sow seed, you’ll have a schedule that worked for your yard.