Its empty spaces echo with the memories of more productive times.

Light-filled, cavernous and still warm, the glasshouses at Briarneuk Nursery in Carluke span almost two acres and, with their state-of-the-art heating, ventilation and irrigation systems, helped make Jim Craig the largest producer of tomatoes in Scotland. Until now.

Craig has devoted a lifetime to growing 14 varieties such as Calvano and Dencore Scotch rounds, Ladner and Lajeune yellows, Revelino mini plums and Claree red cherries. But now, at the age of 65, he and his wife, Liz – who joined the family business 40 years ago – are retiring, and he has not actively sought a buyer to take over the nursery.

J&M Craig was founded by Craig's grandfather, who switched from growing fruit to tomatoes in 1953, and passed the business on to Craig's father. Craig says he himself was "born into the industry". His decisive move puts into question the future of the Scottish tomato industry, but even so he has had enough.

"The reason we're stopping isn't that the business isn't viable, it's that we are growing older and it's getting to be much harder work," he says. "Growing tomatoes is a year-round job that can mean a 70-hour, seven-day working week. We've no family to pass it on to, so this could well be the end of the business."

It seems incredible that the Scottish tomato could completely disappear from our diet. During the 1950s and 1960s, the Clyde Valley was famous for them. It once had hundreds of growers and acres of glasshouses as far as the eye could see. But J&M Craig is the largest of only three commercial growers still active in central Scotland, the others operating on a smaller scale. Craig says the EU has adversely affected the potential for selling his product in supermarkets.

He is still smarting from the failure of Scotland's Tomatoes, a brand launched by a collective of individual Clyde Valley growers some 20 years ago in an attempt to market and sell their produce in the face of increasing competition from imports. Although the initiative worked initially – at one point Craig was selling 250 tonnes of classic round Scottish tomatoes a year – the ever-powerful supermarkets were reluctant to commit themselves 100% to the brand. "They wanted to keep their options open, because there was so much cheap produce available from other countries and they didn't want to risk missing out on cheaper opportunities," he explains. "They were also concentrating on increasing the presence of their own labels, and branded products such as Scotland's Tomatoes were given less opportunity.

"We got squeezed and squeezed. Supermarkets will give you a contract to say they'll take your product, but not how much they'll pay you. There's a consistent erosion of the price, through BOGOFs [buy-one-get-one-free offers] or from cheaper imports from Poland and Romania, which are overtaking Holland and Spain. The price you got for your tomatoes was based on what they were paying the Greeks and Spaniards, which was no use to us. They grow their tomatoes outside in the sun. It's more expensive to grow them here."

So Craig abandoned the supermarkets and became independent again 12 years ago, selling at farmers markets with a vastly expanded range. This proved much more successful and led to expansion to farm shops, gardening centres and outlets such as House Of Bruar. Some 70 tonnes were sold this way each year – and although the volume was smaller than the Scotch rounds, the tomatoes weren't as big. However, Craig was able to sell them at a better price.

This meant full production in his glasshouses, which were built in 1989. Until this summer, Craig and his wife were tending about 20,000 plants, which yielded steady crops from April through to November each year. The plants were always purchased from the same supplier in Hull, who would bring on bespoke seedlings from seeds chosen by Craig, who would plant them out in specialist growbags from mid-January.

Craig may be glad to be giving up after all these years, but he is conflicted. The work involved in growing tomatoes in Scotland – where the light levels are lower and the climate cooler than the Isle of Wight, where most of Britain's tomatoes are currently grown – is relentless and physically challenging. On the other hand, he is concerned that the skills and experience he's gained over his lifetime will be lost.

However, he can be rightfully proud that, against the odds, he has established a market for his local, fresh produce whose distinctive sharp flavour is unique to our climate.

"Isle of Wight tomatoes are at least three days old by the time they get here," he points out.

The demand for indigenous crops is growing once again, and the artisan nature of Craig's tomatoes – grown locally and tended and collected by hand – gives them an environmental advantage over cheaper imported varieties and even those from the Isle of Wight.

For the time being, Jim Craig is still living on site and maintaining his glasshouses. Watch this space for further news.