Q: What is the ideal temperature ?
A: Plants utilize photosynthesis...
== light + water + co2 = glucose + oxygen
The symbiotic relationship means that if you can supplement your indoor grow with the maximum allowed amount of carbon dioxide, the correct amount of water, and adequate light your room will run tiptop.
CO2 is very often underestimated but equally important as water and quality of light.
If running co2, ideal temp should not exceed 85°