The Cullens have one combine cutting the 2,100ac and one sprayer.
"We can get through 100 acres a day cutting. We start between 9.0 and 9.30 in the morning and everyone is home for 10.0 at night," says John.
"It used to be 2.0 in the morning but we try just to make a day's work of it now rather than going on all night."
Having reduced costs, John says they're now improving productivity on the land that they have.
"We've switched from plough base to eco-till, to try and build up the organic matter in the ground and get worms back into it," he says.
"We're also growing cover crops to try boost the soil matter and trying to get soil fertility at its best."
John owns a third, rents a third and share-farms a third of the total land farmed within a 20-mile radius of the home in Ballymurn.
John explains that he is share-farming typically with older farmers who may want more control over what happens with the land, or haven't decided what they want to do with it long term.
"Many of them still have an interest in farming and want to keep farming for as long as they can, or their sons are away and future plans are up in the air," he says.
John, a father of five girls, says leasing sometimes works better, as he has more control with the decision-making process on the farm; most of his are long-term leases, with seven years being the average.
"The longer the leases, the better for us so we can forward-plan," he says.
"We have a great relationship with the landowners we are leasing from, we look after their land as if it was our own."
Although there is much competition for land in his area, John said that if he could get another 500ac under the Cullen name it wouldn't be much extra work for them.
"Another 500ac would be great, we have the machines to do it," he says.
"The problem is at the moment, of the 2,100ac, about 1,500ac is sowed in winter cereals which is just over a week's work for my brother - he can sow 1,100acres a week.
"We're at this acreage now for a while and we're no different to anyone else - we'd like to get another bit but it's not happening with the competition with dairying and potatoes and vegetable growers in the area.
"So, for now, we're looking to make more out of the land we have."
Swapping town life for the hard graft of farming
"We work serious hours here. When Karen and I got married first she didn't see much of me when we were at the sugar beet, but I'm able to take a step back now," says John Cullen.
"I do take holidays and weekends away from it. You need it to keep your head right."
Originally from Gorey town, Karen settled in fast and never shied away from hard work. Now she says that she much prefers the busy life of being a tillage farmer.
"I remember sitting on a tractor at eight months pregnant and our eldest daughter was four at the time, going around the field picking up beet. It was a long way from living in the town - but I wouldn't change a thing," she says.
As if being a tillage farmer wasn't enough of work, John is also a grain merchant - he runs John Cullen Grain Ltd - and more recently has become a feed merchant, in case he had a few minutes to spare.
It's clear the Cullens have a strong commitment to adding value to their own and purchased produce, sourcing only locally produced grain for their coarse mill plant, Cullen Mills.
They now employ 12 full-time staff as well as hiring extra help during the harvest.
"Beans were getting very popular here and we saw an opening for a mill and to use local produce," says John.
"It's growing all the time, we're only in our infancy - a lot of farmers are happy that it's Irish grown ingredients."
This year, most of the acreage is for winter barley yielding 3.45t/ac on the year gone out; other contenders include winter wheat, oil seed rape, spring barley and beans.