About 10 years ago I did some frost prevention. Basicly, it was my very first job. We used to fly with two pilots, one to wake up the other when he fell asleep
The operation was totally unprofessional (doors removed on one site, copilot usind a flash light to point out the wires
) but very adventurous and a lot of fun.
What was very astonishing is the fact that the very next morning you could exactly see those spots you missed with your downwash. Those tomatoes didn't look too healthy.
Good advice is to get yourself a big thermos flask with some hot coffee, tea or chocolate.