co2 any one???

i havnt found much info on co2 if any one could answer many thanks i currently use either water suger and yeast or baking soda and viniger to produce co2 but the reaction only lasts 2 to 3 hours max so is there a time of day when plants would use it the most??? also just repoted some plants and gave them a good watering in new tub but the leaf edges are raising up it looks like heat stress from grow lamp but this is not the problem niether is air flow could it be transplant shock over watering can any one diagnose the problem???