So July is here and temperatures in the greenhouse are soaring, to 110 degrees recently, probably 115 or higher with the humidity. And this isn't the end. However, Dr. Pattison has generously donated light-meter measurements that a student of hers will be making twice weekly by stepping into the greenhouse and measuring the light intensity (lux). This will help to create a record, over time, of how much light comes into the greenhouse, and, more importantly, how much shade we need.
Speaking of shade, I'm looking into buying a large roll of aluminet, probably 50% light blocking. Aluminet has the advantage of diffusing light and retaining it much less than simple black shade cloth. This property, however, makes it at least 1/3 more expensive than the usual cloth. Nevertheless, aluminet it will stay.
Recently, I visited AAA Texas Hydroponics & Organics(Street view here). It's a great store, and Chris, the manager, know tons about greenhouses. He recommended moving the entire volume of air in the greenhouse once a minute, shuttling it in and out. Without the movement, the heat and humidity are too much for most plants, just as we are experiencing right now in our own greenhouse. His fan costs $400, but he told me to get a large exhaust-type fan, from farmtek.com (great site). He also identified a fungus afflicting our eggplants just by looking at a leaf, and sold me exactly what would solve the problem, namely, SP-90 wetting agent at 5ml/gallon. Overall, definitely a place to go to if you need urgent troubleshooting or for any greenhouse and hydroponics needs.
That's all for now, so be well. Remember, if you are in the greenhouse, spray the thermometer of the large MODINE heater/cooler with cold tap water for a bit so that it turns on. In addition, drink lots of water (I don't want to be liable for your heat stroke). There are bottles of water under the heater.