Karl Johnson

SEDDON PARK

TURF MANAGER
Hamilton, New Zealand

After 35 years in the turf industry, Karl Johnson still feels like he’s a lucky man.

“I get paid to be involved in sport, work outside and see special events, so I consider myself pretty lucky,” Karl said.

Karl helped to build The Sevens Stadium in Dubai, which included seven rugby fields and six cricket pitches, and has advised on turf management in India, the United States, Fiji, Japan, Kuwait and Samoa.

Karl views the turf as a ‘stage’ for sporting events such as Super Rugby, World Cup Cricket and the 2023 FIFA Women’s World Cup, as well as the Crusty Demons Freestyle Motocross and Kiwi Gridiron.

“We live and work in a fishbowl. Most of these events are televised and there can be millions watching what we do. Expectations have risen as well – everyone wants to know how fast the field drains, how hard it is.”

“The hybrid turf has been the biggest change. It’s amazing to see it absorb the pressure of two 800-kg rugby scrums!”

But the Turf Manager of FMG Stadium Waikato and Seddon Park Cricket Ground isn’t too proud to weed his own ryegrass lawn at home on the family’s lifestyle block in Hamilton, New Zealand.

“The neighbours know what I do for a job so they’re always looking over the fence. I do a lot of hand weeding with a little screwdriver,” Karl said.

“I prefer not to spray, and I think if you have a good, dense, healthy sward of grass, the weeds will struggle to get established.”

How to manage weeds

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Tip 1: Identify which weeds you have

Find out which weeds are common in your lawn. If you can’t recognise them or identify online, take a photo to your nearest gardening centre. The most common are bindii, usually a sign of a compacted lawn; clover, which often attracts bees, so spray when it’s not flowering and spray twice; oxalis, which looks similar to clover; nutgrass, a lover of wet soils; lamb’s tongue or plantain, which grows in a rosette pattern; winter grass, which dies off in summer but has already set seed for next year; and moss, which grows where there’s not enough sun or there’s poor drainage.

Tip 2: Spray safely and apply at the right time

Apply chemicals correctly to achieve effective results. It's best not to apply the herbicide if rain is forecast in the next 24 hours. Rain will either dilute your weed killer or cause it to spread to areas you didn't want it. Follow the recommendations on the label. Some of the stronger chemicals may require safety glasses, gloves and a chemical mask. Make sure that any pets or children are out of harm's way and can't get back onto the grass before it's safe again. Some weed killers may require a couple of applications before they get rid of all your weeds. And some, like a total herbicide, kill everything, so don’t let it drift on to your garden or lawn. Keep all chemicals locked up securely.

Tip 3: Choose the right herbicide

A broadleaf herbicide contains multiple ingredients and is great at killing broadleaf or flat weeds like clover, daisy, oxalis and other weeds. Then there are herbicides that are more targeted for one type of weed, like Onehunga weed, ryegrass or flat weed. To professionally keep weeds at bay, use a pre-emergent. They stay in the soil and when weed seeds germinate, the first root absorbs the herbicide and dies. These are used in professional turf. A total herbicide kills everything, so only use it to kill off an existing lawn if you plan to replace it.

For a natural alternative to herbicides, mix 3.5L of white vinegar with one cup of salt and a tablespoon of liquid dishwashing soap and spray weeds at the sunniest time of day. Dish soap makes the liquid stick and the acid and salt take moisture away. The downside is that the formula can’t get down to the root system, so multiple treatments will be required.

Tip 4: Hand weed and time it right

If your lawn only has a few weeds here and there, pull them out by hand but make sure you get the roots. Annual weeds are shallow but perennial weeds like dandelion and thistle have deep roots and if a small piece of root is left in the ground, they will grow back. Pull out weeds when they are young and your soil is moist, and dispose of straight away. If you don’t have many weeds, you can spot treat with a ready-to-use product. Weed control is best done in September before weeds are able to start setting their seed, to reduce the amount of seeds in the soil.

Tip 5: Empower your turf

A stressed lawn has a higher chance of being taken over by weeds. Follow a herbicide with a lawn fertiliser about a week later. During the growing season, feed it a fertiliser every six to eight weeks, to keep it thick and lush and choke out weeds. Raise your mower height. Grass that is thick and tall deprives weeds seeds of the sunlight they need to sprout. Water deeply and infrequently, to ensure the lawn grows deep roots so it can compete with weeds.

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