Here comes the heat - Orchid Board

estación seca · #1 05-31-2016, 11:37 PM

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.

silken · #2 05-31-2016, 11:50 PM

Good luck. The evaporative cooler should help a lot if the outside air stays dry. I feel frustrated when my greenhouse area gets warmer than 90F Well, I don't like 90F either, but our nights do cool off. Do yours?

estación seca · #3 06-01-2016, 12:08 AM

Now, our nights cool off into the 60s or 70s F / 17-26C. When the real heat hits, in July, nights are almost always over 80 F / 26.5C. Nights can reach 90-95 F / 32-35C or higher at times. We can't grow (outside) most plants in the Crassula family, nor Tillandsias, because of the hot nights. Many cacti need to be treated here as summer-dormant. They mostly grow late winter until nights get hot, and again in fall until days get cool. Cacti love hot days and cool nights, since they have crassulacean acid metabolism.

Nights here begin cooling down again in mid October. Halloween is too hot during the day for regular costumes, and too cold during the night for skimpy costumes (antifreeze beverages help.)

silken · #4 06-01-2016, 10:36 AM

Quote:

Originally Posted by estación seca

Now, our nights cool off into the 60s or 70s F / 17-26C. When the real heat hits, in July, nights are almost always over 80 F / 26.5C. Nights can reach 90-95 F / 32-35C or higher at times. We can't grow (outside) most plants in the Crassula family, nor Tillandsias, because of the hot nights. Many cacti need to be treated here as summer-dormant. They mostly grow late winter until nights get hot, and again in fall until days get cool. Cacti love hot days and cool nights, since they have crassulacean acid metabolism.

Nights here begin cooling down again in mid October. Halloween is too hot during the day for regular costumes, and too cold during the night for skimpy costumes (antifreeze beverages help.)

I think if I come visit, it will be in winter

No-Pro-mwa · #5 06-01-2016, 12:29 PM

Oh man I'm having a hot flash just thinking about those temps. It would just kill me. We have had a very nice spring as well, slowly warming up. I love it. It is suppose to get into the 80's at the end of the week and I'm going, no not yet. When it gets higher 80's and into the 90's I start to melt.

If we have a couple of days into the 80's I'm going dear hubby it's time to put in the swamp cooler.

rbarata · #6 06-01-2016, 12:50 PM

This year's spring was atypical. Usually in May we have temps around high 80's (25~30ºC) but this year we got only high 60's to low 70´s during the day and 55 F and lower by night time.
Humidity fluctuates between 23 and 87%. Still not enough to reschedule my watering regime.

estación seca · #7 06-01-2016, 04:49 PM

My mom will only visit in December and January.

Plodde · #8 06-01-2016, 05:23 PM

estacion seca, i feel your pain!!!!
not looking forward to those constant double digit numbers.
But the warm nights are actually something i enjoy very much! as long as when its time to go to sleep i can have my bedroom at 70F

stonedragonfarms · #9 06-01-2016, 06:34 PM

Do you use any shade cloth on the outside of your sun room in the spring/summer months?

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estación seca · #10 06-01-2016, 06:58 PM

I have some 50% shade cloth up. It's necessary in the winter when the sun is lower and shines directly in for 5-6 hours. Now, with the sun so high, I probably don't need it at all. A good fan or the evaporative cooler blowing on the plants in the window keeps them from burning in the early morning, the only time the sun hits the glass now.