29 C.F.R. § 780.143

The fact that a practice performed on a farm is not performed by or for the farmer is a strong indication that it is not performed in connection with the farming operations there conducted. Thus, where such an employer other than the farmer performs certain work on a farm solely for himself in furtherance of his own enterprise, the practice cannot ordinarily be regarded as performed in connection with farming operations conducted on the farm. For example, it is clear that the work of employees of a utility company in trimming and cutting trees for power and communications lines is part of a nonfarming enterprise outside the scope of agriculture. When a packer of vegetables or dehydrator of alfalfa buys the standing crop from the farmer, harvests it with his own crew of employees, and transports the harvested crop to his off-the-farm packing or dehydrating plant, the transporting and plant employees, who are not engaged in “primary” agriculture as are the harvesting employees (see NLRB v. Olaa Sugar Co., 242 F. 2d 714), are clearly not agricultural employees. Such an employer cannot automatically become an agricultural employer by merely transferring the plant operations to the farm so as to meet the “on a farm” requirement. His employees will continue outside the scope of agriculture if the packing or dehydrating is not in reality done for the farmer. The question of for whom the practices are performed is one of fact. In determining the question, however, the fact that prior to the performance of the packing or dehydrating operations, the farmer has relinquished title and divested himself of further responsibility with respect to the product, is highly significant.