when theyre vegging you want around 18 or more hours of light a day. 12 hours light and 12 hrs dark for flowering like korvet said
and molasses and brown sugar will probly attract more bugs if you use too much of it or use it too frequently.
molasses is real good for plants during flowering though, so id just wait to use it til then.
if you want to keep bugs away use garlic, theres lots of garlic based bug repellent recipes on the internet, most just say to mix a lot of chopped up garlic with water and spray around the plants