Kohlrabi leaves are lot like collards -- good eating! Here in Oregon's Willamette Valley, I've had two kinds. One is an early spring version that is ready within just a few weeks from transplanting, but it doesn't get very big. The other is like yours -- much larger and it takes longer to grow. I like your type much better. I'm glad it's doing so well for you there in Mexico! Maybe you can use your gray water to get through the dry season.