Unique nailed it! Like he said, that chart is my bible for the first 1/2-2/3 of the plant's life cycle, and I swear by it, but come into week 3 or 4 of flower I just aim to keep my humidity in the room right around 50 and temps between 70-75. So long as humidity levels don't spike above 55% and temps stay low, things usually go without a hitch.
I try to tell people who are new to growing to just use that chart as a reference point, not a guide. Got a question about your grow environment? Refer to the chart!
To answer your question, rudies can sometimes survive lower temperatures than their photo cousins, but again like Unique said, it will drastically effect the plants performance, rate of growth and yield. When the root system encounters cool temperatures the plant often times goes into a dormant stage and does not grow. Equally as off putting, if you are growing in an organic soil base often times the organic minerals in the soil become immobile when temperatures drop below a certain range, and deficiencies quickly show up.... Often times strange ones like zinc, copper, sulfur or molybdenum deficiencies. Just some food for thought!
