As an organic vegetable grower trying to fill 50,000 boxes with a varied selection of vegetables 51 weeks a year – while juggling the needs of our 70,000 customers, 600 staff and 100 suppliers, plus our environment impact – Brexit is a cloud that complicates every decision, every day.

When the sun is out, looking 10 years forward and given sensible, consistent leadership I can (just) imagine UK food, farming and wildlife thriving outside the EU. In that distant utopia we would be eating more local and seasonal food, more plants and fewer animals from smaller producers known by their customers and supported, not just for the food they produce, but for their care for soil, wildlife and livestock and the access they offer to the public.

These genuine custodians of the land would use fewer, if any, pesticides and be supported and protected from world markets with lower standards. Michael Gove’s “public money for public goods” suggests a similar vision, though it is questionable how far it will survive trade negotiations, or whether he will be around long enough to be held to account for his warm, if slightly woolly, promises.

With 79 days left to the day the UK leaves the European Union, our utopia seems an ever‑receding dream, especially when those leading the Brexit charge seem so woefully ignorant of our industry. A “leave‑backing former cabinet minister” recently stated: “We won’t be able to get certain foods like bananas or tomatoes but it’s not like we won’t be able to eat. And we’ll be leaving at a time when British produce is beginning to come into season so it’s the best possible time to leave with no deal.”

I long for a return to reasoned debate; facts really should matter in determining policy

March, though, is the worst possible time for a no-deal Brexit. Weather permitting, some crops will have been planted (this time last year, very few had been) but, dear politicians, they need time to grow: 29 March is, in fact, the start of the UK “hungry gap” when last year’s crops of kale, cabbage, greens, cauliflower, carrots, parsnips, swedes and stored apples, onions and potatoes are all coming to an end, while harvest of new-season crops will not start until mid-May.

Indeed, fresh UK veg is scarce until June. As a nation we import about 50% of our fruit and vegetables (for Riverford it is about 30%) but that figure starts rising in the new year, reaching about 80% in April before falling again in June. If there was a “best time for a no-deal Brexit”, it would be July to September, as any gardener could tell our politicians.

For 30 years Riverford has struggled with this reality – we even suspend our UK-only veg box from March to June because we often cannot find eight UK-grown items to put in it.

Over 20 years, we have developed a network of suppliers across Spain, Italy and France to bridge the hungry gap. Most are small and medium-sized organic farms who have become firm friends as well as trading partners. To see our businesses and relationships destroyed in the name of soundbites, bigotry and ignorance is disheartening. We will never grow lemons but with time, education and investment our diets and farming could adapt to be less dependent on imports, although the change will take years, not months.

Michael Gove and his fellow Brexiters may have had a point when suggesting the public had “had enough of experts”, but after 18 months of fractious and divisive campaigning driven by entrenched unlistening belief, I long for a return to reasoned debate. Facts really should matter in determining policy. Utopia, should Brexiters ever agree on its form, can only be delivered by leaders making decisions guided by consideration, and judgment based on sound information, not dogma and political ambition.

Were we to leave without a deal there couldn’t be a worse time than 29 March, unless you like woody swedes and sprouting potatoes. As for bananas, they are a tropical fruit with 99% coming from outside the EU anyway.

• Guy Singh-Watson is founder of organic veg box company Riverford