Tips for Autumn lawn care

We've had a dry but not particularly hot Summer. With some lingering warmth still around, Autumn is a great opportunity to prepare your lawn for Winter.

Autumn is a beautiful time of year for a lawn.  With the combination of rainfall and lingering summer warmth, lawns get a chance to recover from the heat and dryness of summer.  Lawns that were previously brown and drought-stressed begin to re-shoot and grow back their lush, green blades. With these ideal environmental conditions, it is the perfect opportunity to prepare your lawn for a much harsher time of year – Winter!

Over the next month or so, as the weather cools, your lawn will start to slow down and go into winter dormancy.  With this in mind, you have a unique opportunity over the next month to do some key things to ensure your lawn stays healthier and greener for longer.

The most common lawns in Adelaide are warm-season grasses.  That simply means that your lawn prefers the warmer seasons to Winter.  When temperatures get over 24 degrees, they will actively grow.  When temperatures fall under 24 degrees, as we creep into Winter, they begin to go into dormancy.  These lawns include kikuyu, couch and buffalo. Most people associate Winter dormancy with brown lawns, and although it is a fair assumption to make, there are some things you should know because, armed with the right information, you can act now to reduce the effects of Winter dormancy on your lawn.  Autumn is the prime time to gear your lawn up for Winter.  The better you can get your lawn looking now, the better it will be in Winter.  Once we arrive in Winter, it’s all too late to do anything.  

Fertilising:

I would have to say that the most important thing that you can do in Autumn is to fertilise your lawn.  The timing of your application is important.  Aim for early to mid-April. This will allow your lawn enough time to absorb the nutrient while it is still active but not enough time to use it all before Winter. You’ll need a fertiliser with high potassium and a little bit of phosphorous, and that generally means a mineral-type fertiliser rather than an organic one.  I can recommend one called Paul Munns Emerald Green.

These two elements do very important things for your lawn, namely:

Potassium (K): Reduces transpiration (loss of water through the blades), so your grass needs less water.  It strengthens leaf blades, enabling grass to recover from heavy foot traffic and helps grass withstand cold stress.

Phosphorus (P): Promotes strong root development and winter hardiness.  It helps grass withstand environmental stress.  Grass well supplied with phosphorus is less likely to become diseased.

Lawns that are fertilised now are better able to cope with the rigours of Winter.  They will stay greener longer and stand up to frosty conditions better.  They will also fight off some of the common fungal diseases more effectively.

Before applying lawn fertiliser, spray out a liquid wetting agent.  After Summer, soil can often become water-repellent, so water won’t penetrate properly.  A wetting agent will ensure that any water movement that occurs in the soil happens evenly.  Since water is what carries nutrients to the root zone of the lawn, it makes sense that an application of a wetting agent is a great pre-treatment that you can do to ensure that the nutrients filter through evenly when you water the fertiliser in.  Not only is it helpful in delivering nutrients to the roots of the lawn, but it will also help you best take advantage of Autumn rains.  

Fix up bare patches.

If you have some bare patches in your lawn, it’s an ideal time to oversow with some lawn seed or fill them in with instant turf.  Seed such as tall fescue and fine-leaf rye will germinate now and keep your lawn green and full through Winter, and while the soil is still warm, it remains an ideal time to install instant turf.  

Adjust your watering schedule.

As the weather cools down, you won’t need to water as much.  If you have an automated irrigation system, reprogram your computer to compensate for the extra rain around when it arrives – you don’t want to overdo the water in Autumn and Winter as it will only lead to problems.

Get ready for the weeds.

Once the cooler weather and Winter rains set in, you will likely start seeing weeds.  Be ready to knock them down with some selective herbicide as soon as they appear so that they don’t become dominant.  For broadleaf weeds, I’d suggest a selective broadleaf herbicide such as Amgrow Bin-Die.

It’s safe for use on most lawns, including buffalo, which is often more sensitive to chemicals than other lawns.  For the best results while having less impact on the environment, avoid chemicals containing Dicamba.  Dicamba is present in many common selective herbicides, so it’s worth looking at the active ingredients in the chemical you buy. 

While I’m on weeds, in most cases, if you haven’t seen winter grass emerge in your lawn, it’s not too late to apply a pre-emergent herbicide such as Spartan.  Using pre-emergent herbicides like Spartan is a brilliant way to ensure that weed seeds don’t get a chance to germinate. If you’re thinking about doing this, I’d recommend doing it before the end of March.

Raise your mower height.

One thing you should do soon is raise your mower height.  This will leave more blades present on your lawn which will add to its overall greenness.  It will also make it a lot less likely for you to scalp your lawn.  Scalping is where you cut your lawn too low, effectively removing all the blades and leaving those familiar brown swirl marks from your mower.  During the warm weather, your lawn will quickly recover from this because it is actively growing, but because your lawn will virtually stop growing during the Winter, it won’t be able to grow back any new blades till Spring.  

The best time to do this is mid to late April.  Raise your mower height by one notch and keep it on this setting till the end of September.  As soon as Spring starts, take it down to where it was before Winter.

Things to avoid during Autumn.

Given that your lawn will be preparing to go into winter dormancy, I'd recommend avoiding the following things during Autumn

• Scapling,
• Scarifying
• Coring
• Top Dressing 

While none of these activities will damage your lawn, most of them will disrupt it or remove colour from it and there may not be enough time prior to Winter for it to recover.

Outside of these things, your lawn will most likely take care of itself during Winter with very little input from you.  While warm-season grasses go dormant during Winter, they should not go brown (except if exposed to frost).  If you do happen to notice irregular areas of lawn dying off, take a core sample and bring it down to us at Hove as soon as you can.  We’ll help you to understand what’s going on and how to fix it.