Is there a regulation grass height for football?

Question

The grass or turf of a playing field can greatly affect gameplay, as grass affects the spin of the ball, traction / drag, among other things.

In FIFA's Laws of the Game booklet, there is little specified about natural playing surfaces. The blurb only applies to artificial turf:

The colour of artificial surfaces must be green.

... the [artificial] surface must meet the requirements of the FIFA Quality Concept for Football Turf or the International Artificial Turf Standard, unless special dispensation is given by FIFA.

Are there any regulations on grass height, density etc?

Answer 1

Found in 2015/16 UEFA Regulations

IV - Stadium Infrastructure 29.02

For natural pitches, the height of the grass may not, in principle, exceed 30mm and the entire playing surface must be cut to the same height. The height of the cut should be the same for both the training sessions and the match. If deemed necessary by the referee or a UEFA match officer, the home club may be requested to reduce the height of the grass for the match and training sessions