Had water and light. All they need. It was not even warm, and now look at this as if you would not get the heat. And I had never had any problems with it. On the contrary, the warmer and more humid it was in my greenhouse, the faster they grew. (As long as they have had enough water)
For me, definitely not advise! 1 plant I have yet. Unfortunately, there is probably nothing more with tons of sunflower in the garden for this year ...