"We've probably done 250 to 300 hectares this past week," he said in late October.
"People are a bit more conscious about chemical use."
The fertiliser is made by United Fisheries, in Christchurch, utilising 40 per cent of the fish that would otherwise go to waste.
With the Government planning to cap nitrogen fertiliser use, farmers had to look at alternatives such as Bio Marinus, Hutton said.
"It's a good thing, I think, in terms of the Wakatipu."
He still uses Roundup, but accepts it is a controversial product.
"We're moving to using it in conjunction with the product called Fulvic acid, so it's reducing chemical use."
"In terms of chemical use, over the average farm, it's minimal —you go to somewhere like the market gardens in South Auckland, it's massive."
Hutton said his spraying company, Oregon Agriculture, was getting busier every year.
"My main customer base is the farmers but we are doing a lot of lifestyle blocks now, keeping everyone's lawns nice and weed free."
Interesting challenges were going on barges to Lake Wakatipu stations Cecil Peak and Halfway Bay, which are inaccessible by road, and driving to Branches Station over the treacherous Skippers Road.
Sometimes he is on the road by 4am to get to Glenorchy, for example.
"We'll try and get there before the wind gets up, and we might not finish till 9 or 10 some days."
Hutton said his spray rig cost about $150,000.
"We're all GPS-guided and computer-controlled."
For about half the time Hutton is also a farmer. He leases five contiguous blocks in the Wakatipu Basin, off Speargrass Flat Rd, and has about 250 head of cattle.
"I just farm it as one farm, really. The area had a good growing climate," he said.
"We get a bit of that spillover rain from that Milford that Wanaka and Cromwell don't get."
"The Crown Range has had some world records for wheat production, so we have good dirt here."
As for the challenges, Mr Hutton said the growing season was shorter than in most other parts of the country.
"The growth starts probably about October, then she starts buttoning off by May — it's a long winter."
"Freight is an issue 'cos we're not on the way to anywhere. But other than that, it's all right."
However, rabbits are a continuing, and even escalating, problem.