My orchids in Chaiyaphum Thailand.
 

My orchids home may not look well organized, but the plants are sharing the space with our community residents every day and evening in this hut made out of bamboo and straw. Our friends and relatives get together all the time for meals and recreation and it seems like we are also a pre-school for all the many small children. Surprizingly, the plants are fairly well organized and are grouped by their family (grex I think).

It has been sooooooo hot here. And for 3 months we had no rain. I did lose a couple of plants due to the intense sunshine and heat. The high humidity here the plants love (I do not). Now all 64 plants are under shade cloths and should be OK even in this heat. They all get hosed down morning and sometimes evenings too. None are in bloom now, but some are growing spikes and even buds.

I have a question: with this extreme heat (40C/100F every day), how should I be fertilizing? I realize every plant is different, but what should I be doing?

In the pictures you will notice the kids sandbox (loose sand with toys), we have 4 hammocks, and an old-fashioned loom that 2 of the Thai ladies make by hand custom rugs/mats and sell them.

Generally speaking, extreme heat means faster growth, but if you're underwatering due to your situation, that's likely to have more of an impact than feeding, so I'd stick to applying a 100 ppm N solution once a week.

I really cannot tell how you have them organized very well from those photos, but as far as the terminology goes, the order is:

1. Genus
2. species - cross or grex if it's a hybrid
3. variety or cultivar

So dendrobiums A & B are of the same genus, but (if hybrids) are different grexes.

The majority will be fine with 40C every day so long as they aren't water stressed. I would continue fertilizing as Ray suggested. I have summer temperatures even above that, and I need to bring a lot of plants into the house. I leave most of them out at 40C however.

We have been between 40C and 45C with high humidity (good for the plants--not for me). This will surprize you: The hottest single day temp that I was ever in was 116F in 2006. Where? Plentywood Montana. People's eyes were burning soon as you walked outside.