Here comes the heat

[estación seca]

We've had a very cool spring, by Phoenix standards.

The number "100 degrees Fahrenheit" / 37.5C is engraved on US minds as an example of extreme heat. Radio stations, and the newspaper here, have contests every year, for customers to guess when we will first hit 100 F.

During the 30+ years I've lived here, we have hit the magic number as early as the first week of March, and as late as the second week of June. Most years we are over 104 F / 40C every day by mid May. But not this year!

We hit 100 F a few weeks back, but temperatures have been back into the 80s F and occasionally 90s / 27-37C since then. This week has been in the low 90s. However! On Thursday we are expecting 115 F / 46C! And hotter Friday and Saturday!

This is my first year growing orchids in my sunroom, rather than in the house. I now have an evaporative cooler. My sunroom has not been much above 95 F / 35C this spring, except the week before I got the cooler, when I may have severely injured some Oncidium hybrids with heat. Fortunately, our relative humidity will be below 10% until the monsoon arrives in early July. Evaporative coolers still cool.

I will bring the Cattleyas, and other plants that tolerate lower humidity, into my house with air conditioning. The plants needing more humidity will stay in the sunroom, since I can keep it much more humid in there. I can open the doors between the sunroom and the house, but then I can't keep a humid room, and I don't think my air conditioning system can cope with house plus sunroom.

This time of year the sunroom only gets direct sun on the windows for about 3 hours, between 6:30 am and
9:30 am. That helps keep it cooler. In the winter it gets a lot more sun. We're about 33 degrees North.


I will keep people informed about how things go.