If you top dressing the orchids with tea leaves, you can do anytime during the day. But at night the variety has to be the type of tea that imbued with lotus petals. Otherwise your orchids will be up all night.oke:
Actually, I know someone who recycles the tea leaves on his plants (not orchids though)
I think that the only advantage to putting tea in the mix would be that it would raise the acidity, and I think that fertilizer already does that pretty well. And, I suppose that if it were decomposed a bit, it could add some nutrients, but if you're already fertilizing, seems unnecessary. The caffeine will will some pests, too... don't know what it will do to the orchids.
BTW, Earl Grey has bergamot oil in it (though in small amounts) which is a citrus oil... might work like Neem. Or it might kill your plants