The hardest winter in a generation has posed grounds staff with some unfamiliar challenges. But experts exhibiting at last month's Harrogate Week had plenty of tips to minimise the chance that your playing surface suffers any lasting damage.

Identify problems

"We are not used to weather like we've just had," says Sports Turf Research Institute (STRI) northern area manager Alistair Beggs. "Long periods of cold weather are more typical of Canada or northern mainland Europe. In this country it's unlikely to get cold enough to kill the grass outright. But it can't metabolise under a cover of ice and snow. Then you find disease problems when it melts."

When the ground underneath is frozen, "ponding" or water build-up can be a problem, especially in dips on golf courses, he says. "As the water freezes, thaws and freezes again, you get 'winter kill'. But the damage might not be immediately apparent."

However, frozen ground has had one benefit. "Underneath the snow you can find snow mould, though this cold spell hasn't caused too much because the ground froze first, before the snow fell," he explains. With its unmistakeable circular patches, snow mould is a particular problem of fine turf such as bowling greens, he says.

"If you know the circumstances are coming, you can use fungicides - and you can begin renovating when the temperatures start to rise, but that may mean re-turfing completely. But even if it looks okay now, you may still get diseases later in the season because the grass is stressed, so you need to be observant."

Myerscough College team leader for sports turf Stewart Brown agrees that snow mould is a risk to watch out for. "It's caused by the same pathogen as Fusarium, a fungus called Microdochium nivale," he says.

"If you sprayed before the snow arrived, then you're probably going to be okay. However, it can still be treated now - though you may have to re-seed the affected patches later."

Feed

Several exhibitors point out that simply cheering up sad-looking pitches with a dose of nitrogen-based fertiliser is unlikely to do much lasting good.

Vitax Amenity sales and marketing manager Mike King says: "You don't just want to put on a lot of nitrogen that will give you a growth spurt but be vulnerable to disease."

Instead, he suggests Amino-Sorb, a liquid additive that replicates the function of amino acids in the root zone. Vital for a variety of plant functions, these are normally synthesised by plants themselves, but they may struggle to do so when stressed.

"It's Red Bull for your grass — it encourages the plants to metabolise and helps them recover from stress more quickly," says King. "A lot of courses and pitches are in quite a state. People are asking for this sort of thing to stop diseases setting in. It's also environmentally friendly — you can't overdose with it."

Amino-Sorb can be mixed with Primo Maxx growth regulator and will also enhance the effectiveness of weedkillers and fungicides, he adds.

Soil Harmony agronomist Mark Atkins suggests another way of working with nature. "The microbes in the soil go to sleep, but if you can keep them active they will kick-start the growth of the turf, but without the flush of growth you get from applying fertiliser directly," he says. "In fact, with this approach you can do without them altogether. I know of rugby pitches that haven't applied any NPK (nitrogen-phosphorus-potassium fertiliser) for three years."

His company supplies BIOS Turf Tonic microbial feed for the purpose. "It's better to do this before the onset of winter though," adds Atkins.

Richard Heywood, a sales manager at VertiDrain supplier Redexim Charterhouse, says a more analytic approach to turf problems can save on precious resources. "Local authorities are coming under more pressure to produce good pitches, which means doing more than just cutting and rolling," he points out. "Knowledge of what needs to be done is higher, but they have less money to spend."

British Seed Houses amenity sales manager Richard Brown suggests an alternative feeding regime. "Iron and potash will harden the grass and boost the root zone," he says.

"By March everyone's busy, so February, when there are not a lot of other jobs, is a good time to put on a controlled-release fertiliser. It will only be used when it's warm and wet but will start fertilising before you actually see the grass growing and will also be taken up more efficiently, so there's less run-off."

Aerate

Soil aeration will also kick-start turf recovery because prolonged wet periods can turn the root zone anaerobic, particularly in the case of fine, compressed sports surfaces. But again, timing is critical.

Synergy Products is a distributor for aerator manufacturer Groundsman Industries. According to director David Meharg: "You need to reinvigorate the turf, which will be more receptive to fertilisers afterwards. But you should check the temperature of the soil first — you risk doing damage when the ground isn't receptive."

Somerset's Bridgwater College trainer and assessor Jake Waites agrees. "Right now you are looking to give turf a tonic and aeration is important to get things moving," he explains. "But if it's too wet, the holes you make will just close up again. Moisture analysis or core samples will give you an indication of that.

"On heavy soil, it may be necessary to wait a while. Our own nine-hole golf course at the college has sand-based greens, which are very free-draining and were back open very quickly."

Mow and roll

According to Richard Brown: "Now's a good time to 'groom' your pitch. The snow will have caused some of the grass to breakdown.

"If you go over it with a cylinder mower, you will pick up the dead bits that would otherwise fall and form a thatch, which will be an environment for diseases. Removing it allows air to flow around remaining grass."

John Lyons School groundsman Daniel Mills says: "If it's dry enough, then rolling regularly will at least ensure that you have a flat playing surface. For a local authority, that need only take around 20 minutes per pitch."

Head groundsman Andrew Robinson adds: "The snow hasn't necessarily been a bad thing. Turf responds well to a rest."

Don't overdo it

Finally, bear in mind that turf is resilient, says Myerscough's Stewart Brown. "A lot of it is just letting nature take its course. You shouldn't go on ground that's still frosted.

"But even when it melts, the ground is likely to be too saturated even to use pedestrian machinery. It will take time for the water to drain away — you don't want to get on there too early."

Further information on dealing with winter turf conditions on golf greens is available from the STRI website at www.stri.co.uk.

A BREATH OF FRESH AIR — IN A LIQUID

One downside of physical aeration is that initially it may only rejuvenate turf sporadically around the tine holes, according to biological agent supplier Symbio, which launched its Liquid Aeration product at the show as an alternative.

Managing director Martin Ward says "Tournaments are starting earlier and earlier. If the grass isn't growing, you can't even out the lumps and bumps."

Liquid Aeration can be combined in the mix with a stimulant, such as Symbio's Soil Association-approved NuGro 8.7.7, to activate dormant microbes in the soil, he adds.

Agronomic Services launched Oxy-Rush. Like Liquid Aeration, this stimulates soil microbes by making oxygen more available. It boosts mycorrhizal activity — useful to species such as bentgrass that have a symbiotic relationship with root fungi and helps to breakdown thatch, allowing freer drainage.

Oxy-Rush can be used on its own in the tank or with Agronomic Services' wetting agent Pervade. According to managing director David Snowden: "Pervade will move water throughout the soil profile and pull the Oxy-Rush into the root zone, increasing the oxygen levels and reduce black layer, algae and anaerobic conditions."