Asparagus and blueberry grower Chinn said the British Growers Association had estimated 80,000 seasonal workers are employed now and that there would be 95,000 by 2020.
He said horticulture needs to trial a new SAWS, with new countries, for instance with Ukraine: "We need a country outside Europe to let us demonstrate, working with the Home Office, we can manage that."
The idea for using Ukraine is because the UK still has free movement in the EU, but not with Ukraine, and the industry needs to prove workers will return home after their stint in the UK. The industry hopes to trial a scheme in 2018 while the UK is still in the EU.
Chinn added: "If we don't have labour we don't have a business. If borders are closed it's a critical issue and that's why I'm here [at the hearing]."
He said there was a "dwindling pool" of EU workers available so "it's critical we look beyond the EU".
Chinn said he had 1,000 seasonal workers, with 94%from Romania and Bulgaria. "We wouldn't have been able to grow the business in the way we have without seasonal labour."
He said workers were finding a "huge amount of uncertainty" and felt "no longer welcome" and were "fearful" of returning.
Chinn said: "We're competing with Europe for labour." He said Cobrey was having to speak to eight people to secure one worker compared to three this time last year.
He said Brexit had an "obvious and dramatic impact on recruitment". Chinn added that living wage had increased labour costs by 15% but workers were getting 20% less because of exchange rates, adding: "In the current climate paying more is not very palatable."
HTA policy adviser David Brown said there were 75,000 temporary and 10,000 permanent EU workers in horticulture with 120,000 overall in retail.
He said reports from Bulgarian representatives at the European Nurserystock Association last month were that Bulgarian workers were "deterred" by reports of UK post-Brexit xenophobia and might receive a "warmer welcome" in Scandinavia.
Brown said in his 30 years experience of SAWS the scheme has worked well but "frank discussions are needed" about future numbers. He said there is a need to clarify the situation for people already here and that "we need new people moving forward".
Brown said UK plant production at £1.1bn was at the same level as imports, but there was potential to change that in Britain's favour.
Kerry McCarthy MP raised the issue of food security linked to the iceberg lettuce shortage caused by bad weather in Spain.
Chinn said the UK was 50% self-sufficient in fruit and veg.
Committee chairman Neil Parish MP said: "We as a committee are very concerned about supply of labour for both the farming and horticulture sectors."
Parish said we're going to have to make it clear we welcome EU workers at least in the next two years. He said it was partly the concept about their welcome here people were worried about.
Also giving evidence were John Hardman, director, Hops Labour Solutions, David Camp, chief executive, Association of Labour Providers and Chris Rose, commercial controller, The Asplins Producer Organisation.
The Environment, Food and Rural Affairs Committee inquiry into the challenges to the food supply chain from shortages of workers asked: "UK food production depends on securing an adequate supply of labour to get the harvest in and to process the produce. But farm and factory businesses have reported, both prior to and since the EU referendum, that they find it hard to hire enough workers. Each year farms rely on tens of thousands of temporary workers, with some 80,000 of these workers currently coming from outside the UK."
- What are the economic impacts on farm and food supply chain businesses and on consumers from problems in securing adequate labour supplies?
- What is the impact likely to be of changes to freedom of movement rules post-Brexit on the flow of EU and non-EU labour to UK farms and factories?
- What should the Government do to ensure a sufficient labour supply to meet the needs of farmers and food production businesses:
- What sort of immigration rules need to be in place to allow farm and food businesses to employ EU and non-EU nationals in skilled, semi-skilled and unskilled jobs?
- What contribution could seasonal workers schemes provide to addressing labour shortages?
- What should the Government and the food and farming sectors be doing to attract and retain UK workers for all parts of the food supply chain?
Last month, NFU Director of Policy Andrew Clark gave evidence to the Department of Work and Pensions (DWP) Select Committee in a one-off session on the potential impact of Britain’s exit from the EU on the ability of UK firms to recruit the workers they need.