BIXBY, Okla. — Harvest starts early in the morning hours at the OSU Mingo Valley Research Station, where up to 2 dozen Tulsa County Master Gardeners volunteers fan out each week to pick whatever is ripe: okra, cucumbers, green beans, peppers, squash, carrots, and more. Volunteer Teri Holmes said she found her calling there after retiring. "When I retired, I said, Hey, this is where I want to be.