If you purchased the plants at a LFS or online retailer you may experience some "die off" as they acclimate to your water source. As plant growth slows or ceases (from lack of "food", low lighting levels, or during acclimation) algae growth usually increases.
Are you "feeding"or fertilizing the plants? Plants need "food" in the form of nitrogen (ammonia/ammonium or nitrates), phosphorous (phosphates), potassium, iron and micro nutrients. In lower light tanks, these needs can usually be met by fish waste and excess food. What is your fish load like?
You can use a toothbrush (similar to twirling a fork in spaghetti) to remove the hair algae. Keep on top of it or it will soon take over your tank. For the algae on the glass, clean the glass followed by a water change. Disturbing the sand with your hand while using a gravel vac above the substrate works well at removing the algae on the sand also. How long are your lights on?