To ensure those vegetables, seed crops and cereals kept growing required plenty of water, and the management of nine irrigators on the 650ha of land they owned and leased.
Eventually, the Cokers realised they wanted an easier lifestyle but, in the search for a new farm, they stipulated it was not to be summer-dry country and they did not want to farm sheep.
"I don't like sheep," Mr Coker said with a wry smile.
The result was a shift three years ago to a 320ha (effective) farm at Dacre in central Southland.
Unlike their dairy farming neighbours, the Cokers run a beef finishing business on what would be ideal terrain for dairying.
"A fair bit of it was family and lifestyle," Mr Coker said of the shift.
"But I have always enjoyed the cattle."
Cattle finishing was a straightforward, low labour cost operation supplying beef that met high specifications to the Canterbury Meat Packers Aleph Programme for export to Japan.
Returns were relative to the schedule at the time, with a premium for meeting the strict criteria.
Mr Coker said last year they finished 950 18-month-old cattle, with steers averaging 300kg and heifers 275kg.
The first intake of 300 to 400 cattle were bought at the autumn calf fairs, with the balance in the spring.
They were finished and sold from the following February to early June.
Their CMP contract has exacting standards.
The cattle must be beef-breed and treated almost to organic standard.
They have a quarantine drench when they arrive and are only drenched when a faecal egg test proves it is needed.
"If they don't need a drench, we don't give them one."
Mr Coker said growth hormones were banned and antibiotics cannot be used, with any treated cattle sold to another market.
The broad application of herbicides was also not allowed on the farm, prompting Mr Coker to use a carpet wiper to control thistles.
Compared to traditional management, Mr Coker said they had cut out at least one drench a year, along with using less pesticide and the more targeted use of herbicides.
"It's definitely cheaper," he said.
Mrs Coker said we should all be eating this quality of beef.
Coming from a cropping industry where a variety of chemicals were applied, she said it was refreshing to be looking at how to use a minimum amount.
All the calves were bought by Mr Coker's local CMP drafter, Wayne Pope.
"He knows what I want and he treats my chequebook like his own."
At the other end of the production cycle, Mr Pope returned to draft the calves for the works, selecting those ready for slaughter and helping select those that would follow in the next few weeks.
Part of the reason for Mr Pope buying the calves was because Mr Coker needed to be on the farm, developing it.
Mr Coker's priority has been building or replacing fences, renewing pasture and some of the buildings, and repairing and building yards.
One of his projects in the last year has been the construction of a wintering shed.
The farm was wet over winter, and while a swede or kale rotation helped with the pasture renewal, Mr Coker said the need to have calves grow over winter meant a change in management.
This year, 330 of the lighter calves went into the 75m by 18m shed in May, where they had a constant supply of grass baleage and slept on a bed of woodchips.
The concrete pad where they were fed was designed to have a fall so all the liquid was collected in a sump at one end and the muck was scraped each week into a bunker at the other.
The effluent was spread over the paddocks.
The rest of the calves were put on a swede and kale crop in mobs of 100.
They were given a fresh break every day along with baleage.
By early September, the calves were back on grass, but Mr Coker said the beauty of the wintering shed was that he had flexibility.
If spring was early, they could be turned out early.
If it was late, they would stay inside.
There was no versatility with calves on crops, as they had to be taken off when the crop was finished.
"The shed gives us greater flexibility when we start and when we finish," Mr Coker said.
Depending on the success of the shed, he may extend it and winter all his calves under cover.
His winter feed budget was 1100 bales of baleage and 10ha of crops and he harvested baleage as a form of pasture control.
Because he did not have a different class of stock to control rampant pasture growth, harvesting baleage was used to control grass in spring and summer, a task made easier because he had his own machinery.
These were often small areas of 4ha to 5ha which Mr Coker said contractors would be reluctant to commit to baling.
To keep up his pasture renewal programme, he intended having a crop in for one year then back into pasture.
Mr and Mrs Coker have been keen to embrace technology.
For the first time this year, as the calves arrived they were tagged with an electronic identification tag.
Eventually, this will provide a mountain of information, including total and daily growth rates, and they will be able to compare the performance of the various lines of calves between herds and between years, with the various pasture varieties and pasture management.
"It is endless what these tag will do as far as management goes," Mr Coker said.
He said some calves had four tags in their ears, but the electronic tags were small buttons which he inserted close to the base of the ear.
He also regularly measures grass growth so they can budget the feed allocation.
For the Cokers, it has been a successful shift south.
They enjoy not being tethered to irrigators over summer, with Mr Coker spending long hours on the land during the cropping season.
Competition and demand for water was looming as a huge issue in Canterbury, even for those like the Cokers who have had access to irrigation for many years.
There is a spot of irony in their shift south.
The calves they carefully manage and prepare for discerning Japanese consumers are trucked north and killed in a meat processing plant about 10km from the Cokers' former Canterbury farm.