Today it was 97°F (~36°C) mid-afternoon. Gus, our two year old Mountain Cur mix (that makes him a mutt’s mutt), found the heat and humidity too much and cooled off in one of our rainwater collection vats. He sat in the water for several minutes before going into our air-conditioned office to shake off the water.
South Texas summers, long and hot, provide some interesting environmental issues for us. Our three greenhouses by their natures collect heat. Sun shines in and the plastic film cover traps the heat. Temperatures soar.
We reduce the temperatures in two ways. First, from early March until late November we cover the greenhouses with 75% shade-cloth, which as its name indicates blocks 75% of the light and heat. Secondly, on hot afternoons we run exhaust fans to help remove hot air and cool the water via enhanced evaporation. Collectively, these steps keep the afternoon water temperatures below 88°F (~31°C). While this may seem warm, it’s actually a good temperature for rapid fish growth, assuming water quality is maintained and adequate aeration provided. Our plant filters provide pristine water conditions, in fact, the higher temperatures ramp up the plants’ metabolisms and they suck ammonia from the system even faster. The combination of our water pumps and air blowers keep the water well aerated, providing adequate oxygen even at such high temperatures.
Even with these cooling efforts we don’t usually work in the greenhouses in the summer from noon to about 4:00 PM. The combination of heat and high humidity is too uncomfortable.