A radiation protection filter for plants wherein tau 1<0.02 tau 3>0.4 tau 3/ tau 4>1.5 tau 4<0.4 tau 5/ tau 4>2 tau 6/ tau 4>2 and wherein tau 1=average of spectral transmittance between 300 and 330 nm. tau 3=average of spectral transmittance between 400 and 500 nm. tau 4=average of spectral transmittance between 500 and 600 nm. tau 5=average of spectral transmittance between 600 and 700 nm. tau 6=average of spectral transmittance between 700 and 800 nm.
