Section 7D. The bureau shall, with the cooperation of other state agencies and cities and towns, compile a list of all vacant land, that in the opinion of the agencies and cities and towns, can be feasibly used for gardening, arbor culture or farming. The bureau shall, by letters of agreement, contract with such agencies or cities and towns for the use of said vacant land. Contracts may contain a termination date. If no date is determined, either party may terminate the contract by written notice given within 60 days; but no contract shall be terminated until the end of the harvest season. The bureau shall notify the gardeners or farmers of the notice of termination.