Pre-approval for consideration was received with Chancellor of the Exchequer Rishi Sunak and Defra secretary of state George Eustice having been informed.
Richardson said: "This is the basis of a letter sent to our MP seeking support for the industry. We would urge all growers to do something similar."
"I promised to brief you on the emerging impact of the current crisis on commercial ornamental horticulture. You have perhaps seen relevant footage on BBC national news this morning?
"Growers have to commit way in advance to ensure the availability of garden and landscape plants at windows of seasonal demand. Easter, in particular, is a focal point for the general public who emerge from winter and turn their attention to their spring garden.
"The ongoing crisis and the necessary lockdown has withdrawn that demand at a stroke resulting in an industry-wide surplus of at least £250m. Many of these crops have a limited window for sale, have limited shelf life, incur significant cost to maintain and then become a long term dilemma as the carried over surplus buts up against subsequent crops of the same item that have had to be produced to meet forecast future demand.
"Without being alarmist, this is simply the most significant issue that our industry has ever faced.
"We believe there is a strong case for government support that will provide financial backing in compensation for wasted stock and for future stock that will waste as a result of postponed contracts, orders and insufficient longevity in the allocated stock. 'Support is required now and should be capable of providing assistance to growers who will have no option but to waste significant tranches of saleable stock both now and in the coming months.'
"I understand that a business case was made to the treasury via the UK Farming Round Table/NFU and HTA on Friday 27 March and that pre-approval for consideration was received. I am also told that Rishi Sunak and George Eustice have been informed.
"In the longer term, our industry will be called on to grow the trees to assist in our meeting an ambitious carbon reduction target, putting it bluntly the industry has to exist in order to do this!
"I would be very grateful for your support and a direct plea to any appropriate instruments of government, including DEFRA and the Treasury."