Whenever you have a potted plant, wherein the soil has dried out completely, you can re-wet it by immersing the pot in a pail of water. Leave it to soak until no more bubbles come to the surface. Be sure to drain the pot well before placing it back on a saucer or other flat surface.

A small drop of liquid dish detergent per gallon of water is a good way to break the surface tension of peat based and other soil mixes that are difficult to replenish moisture content.

Alternatively, you can place/wrap a towel around the base of the plant on top of the dry soil and water the towel. Let the towel stay soaked for an hour or two and remove.

Also, filling up old (or new) Coke bottles with water and plunging them upside down into the dry soil will be effective as well. Within a few hours the soil will have slowly absorbed the water and become plentifully soaked.