Brown spots can/might be the start of a mold infestation. You may want to consider treating with a copper based spray, and/or burning some sulfur periodically. A little prevention goes a long way. If the leaves start to turn yellow later on, as the plant(s) get older, and you see what looks like rust spots (brown circular spots) this can actually be caused by fungus/mold infection. You can also consider running some GE germicidal bulbs, such as the T8 florescent UV bulbs 48" long G36T8 (order #29499 for GE), at three 10 minute intervals on, then off for 30 minutes, per day. These bulbs are full UV, not just the blacklight spectrums, and will kill mold spores on the leaves if the light hits them. These bulbs will also increase natural defense mechanisms in the leaves to buld up a thicker layer of crystal(s)/Oil(s) to help protect the plant against harmful UV light. In a pot plant that means it will increase the production of THC. So, you get protection from rays of light and the plants get fewer mold spores to infect them. Sounds like a plan if your a plant stuck in the basement all day with humitity above 40% and temps that are over 75 degrees, ripe for growing molds. The bulbs list for about $70.00 each and will fit in a cheap T8 48" long light fixture you can buy at Home Depot, Lowes, or Walmart... Chances are the bulbs return a yeild of fruit grown in a basement that far exceeds the loss caused by mold that stunts your plants and gives you a ton of greif, not leaf.