Increasing Humidity? How do you do it?

[Xenophon]

hi all,

i've had problems with some species and i do suspect it's because i do not have enough humidity ( Ironic coming from me because i live in the tropics ) but i've given them sunshine (till mid afternoon), more waterings, less waterings... all don't seem to work. Would repotting help? i heard that if you allow the new bulb's roots to touch hard surfaces like charcoal or the wooden slat basket, there is a higher chance of it booming.

How do you increase the humidity? i already have a tray filled with water and a water feature going. i'm tempted to put some of them into ziplock bags for a few days to make them spike. Just hope they don't rot. Hot + Humid + No aeration = Rot

What do you guys think? and most of all, how do you make certain bulbophyllums boom? (Medusae, Echinolabium, Lobbii) all are mature plants already with more than 10 bulbs!

Cheers,
Freddie