Grow Tent Extension Kits an easy way to increase your Gorilla grow tent height? With the extension kit, additional height provides your heat will stay up by the lights where you want it, and away from your precious plants. Both the 1' & 2' Grow Tent Extension-Kits that will increase the height of your grow tents. The 1 ft. height extension kit gives you the ability to increase your growing height from 6’7? to 7’7?. With this 2-foot height, the extension you will now gain the ability to have a tent that is 8', 9', or even 10' in height, by using either just the 1' kit or the 2' kit.