A cold weather action plan has been set in motion.
Because this early cold front has not been preceded by rain, I have just come in from watering beneath the canopies of large trees. As water retains warmth longer than dry soil, the warmth will radiate up into the canopies tonight, creating a nice microclimate for tender trees and plants growing in the trees.
Hanging baskets are probably drying out now from the wind, so bring them inside. I have several in a lychee that I'll lower to the ground and cover with sheets.
Winterizing plastic encases the orchid houses now. I've put the plastic sides down to keep wind from damaging tropical orchid leaves. Many Vanda orchids have already been brought inside, and soon to follow are the Phalaenopsis orchids. Cattleyas will be OK, but those with open flowers or buds (and there are lots this time of year) should come indoors.
Don't use plastic directly on plants to shield them from the weather as it can carry warmth away from the leaves and chill or kill them. Use old covers or even newspapers if you can weight the material with bricks, stones, etc.
Large-leaf aroids will come inside. I made the rash decision to put Anthurium faustomirandae in the ground and must create a tepee for it with bamboo and sheets. Last year, I even put a flood light beneath its covers to add extra heat.
A follow up regimen is a good idea. For orchids (with the exception of Dendrobium species/hybrids) a mix of Dithane M45 and Kocide -- 1 tablespoon each to a gallon of water -- may help prevent fungus and bacterial infections. Kocide, which is a copper compound, should not be used on bromeliads. Copper used more than twice in a season may be toxic to leaves. Alternatively, use Subdue or Aliette. You may wish to treat palms with the Dithane/Kocide mix, as bud rot hovers at the edge of every cold spell. Or, you may want to roll the dice and wait to see what January brings.