Depending on the plant and its size you should be able to keep it alive in a bucket with a light over top of it without a problem, a simple 5 gallon bucket from the hardware store will do fine, unless you are getting something massive. I always add an air stone or a tiny powerhead to the bucket to help promote good water flow around the plant. You will also want to keep the water at a decent temperature, you can simply wrap the bucket in a few towels and that should help retain some of the heat from the lamps. Even tho I keep the heater set to 70 in my apartment my RODI water storage tank is often only 64-65 degrees.