Tangmere Airfield Nurseries finance director Robert Searle told the Plan To Grow event: "It's vital that Tangmere grows - the public wants us to. The UK is over-reliant on vulnerable imports, while we have the fastest growing population in the EU."
Meanwhile, a traffic-light pack of peppers that used to sell for £1.50 in supermarkets now retails at 99p, while "the minimum wage, work-based pensions and energy prices have a massive effect on margins", and the strong pound "gives producers elsewhere a competitive advantage", Searle pointed out.
"We need to increase volume, find efficiencies and use innovations, all of which require huge investment. The solution for Tangmere is land for more glass - it's a bottleneck to growth. With so many local, national and international benefits, why is it so difficult to grow?"
Councillor Tony Dignum, Chichester District Council leader since May, described a recent visit to Tangmere and other production glasshouses in the area as "an eye-opener for me and my colleagues". He added: "Clearly, they are high-investment, high-technology facilities providing highly skilled jobs and making a major contribution to local and national policy aims."
He added that the council's local plan, adopted in July, would ensure support for horticulture through the planning system. "Horticulture is the second-largest industry in Chichester and Arun districts after tourism, worth over £500m and providing 4,300 permanent and 7,000 seasonal jobs."
The plan emphasises the role of two larger and two smaller Horticultural Development Areas (HDAs) in which "planning permission will be granted for new glasshouse, packhouse and polytunnel developments", subject to conditions, and also promotes retention and construction of accommodation for agricultural workers.
The council's head of planning services Andrew Frost said: "We expect land in HDAs to be used first. Compulsory purchase orders are a possibility here for removing obstacles to development, though that's not a quick process."
But Searle said: "The problem with only building on HDA land is that there's not a lot of it. We have HDA land next door but it isn't for sale and renting isn't viable."
Yet now is as good a time as any to invest in production, HSBC regional agricultural director Martin Redfearn told the conference. "Consumer confidence is growing and interest rates are as low as they'll ever be. That's an opportunity for you guys. If your project is worth lending to, ask us now." He added: "HSBC thinks that with the economy in growth, inflation will take off faster than people think."
Meanwhile, the value of facilities (meaning a range of financing measures) that banks have agreed with UK farmers rose by 29 per cent in the year to September, said Redfearn, adding: "There is a massive amount of money waiting to be lent."
But AHDB Horticulture chairman and outgoing Lea Valley Growers Association chairman Gary Taylor said: "A sustainable industry is one that generates enough income to re-invest. Instead companies are asking, 'do I have enough money to stay in business for the next year?'."