Instead of foam grass I just used green fulfillment for the base.
I didn't find the right tube, so instead I just cutted 0.3mm thich sheet of clear plastic to proper dimensions and taped it together. It has tape from back side, but it's not as noticable.
I'm powering it via USB. Same circuit as original, just instead of 7V I use 5V from USB that is also powering arduino.