I'm no expert but the lighting that you use should keep it heated just fine assuming you are going to be using MH or HPS, I use CFL's and if it starts to get to cold come winter I'm thinking on a heat light or two, depending on how cold it gets.

Correct me if I'm wrong, but you only have to keep the plants warm.

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Humboldt's Growing Adventures! Up & Away!



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Enjoy!