A question on getting hummidity

could i pick anyones brains on how to get hummidity i grow mine in a grow tent that cud hold 9 plants ive got proper lighting,ventilation everything is good just need hummidity i was looking at a pic of a grow and there was plastic cups with water in the trays is that how you produce it with the heat from the lights.thank you for any posts

ur gorinw in a tent and u need more humidity??? i would think u would have to much do to the condensation?????? either way get urself a humidifer or if u cant a fford 1 boil urself a pot of water and place it in the tent