Technical Abstract: Scaling and application of a new pulsejet combustion system for agricultural heating and frost protection purposes that is efficient, environmentally friendly, and economically competitive is described. Buoyant forces of warm air are quite small and a few large heaters appeared to greatly add to the effectiveness of wind machine-based cold protection programs. Scaling criteria was formulated and utilized for fabrication of various sizes of stationary horizontal pulsejet engines (combustors) optimized for orchard heating. Theoretical and empirical approaches resulted in similarity parameters that played an important role in the scale-up for field heating applications. The scaled and optimized heater prototype was constructed and field tested. Experimental results favorably confirmed the applicability of both gaseous and liquid propane as a fuel supply. Heaters were designed to operate in conjunction with vertical wind machines but can also work as a stand-alone heating method. The greatly advanced heater design was tested under orchard conditions and found to circumvent the many disadvantages of conventional oil and liquid propane (LP) gas orchard heating systems, especially when used in combination with wind machines. Thermal efficiencies (heat retained below canopy height) range from 60-75% compared to 10-15% for standard orchard heaters. The number of heaters per hectare can be reduced, heaters can be made larger, per hectare fuel consumption is greatly reduced and the new heating system could be used with or without wind machines. They can be used in spring, fall or winter when field heating may be required for crop protection against cold temperatures.