I'd do bottom heat instead - get one of those seedling heating mats. I
think it's going to be hard to get local heat otherwise. So you're planning
to air condition your place in Houston then if you heat it up with a space
heater, it will be VERY dry.

Now this is why I love this newsgroup. Thanks to you and Gene and others who
have suggested this option. I never thought of it!

Thanks too for the sponge rock definition. Now I know what to go in search of.

Take care,

Tom.