Plot thickens.

I looked at the service box on the barn today and found a 2 pole 50amp circuit that luckily connects to an RV plug just a few feet from the greenhouse. Woo hoo.... Maybe.
The greenhouse has four 20 amp circuit breakers


Correct me if I am wrong.

I know that the double pole means there are two separate power wires each 120v in separate phases to make 240v service.

My questions are this.

Can I split the 50amp two pole breaker into two 50 amp circuits One for two of the 20 amp circuit breakers and one for the other two?