Cotton lint yields of Acala 4–42, Deltapine Smooth Leaf, and Strain A decreased as planting was delayed after March 22, but an earlier planting (March 8) did not increase yields in tests at the Imperial Valley Field Station in 1962 and 1963. Gin turnout (expressed as percentage of lint) of Acala 4-42 increased slightly as planting was delayed, but decreased in Strain A and DPL-SL. There seems to be no advantage in planting cotton before March 20 in the southern part of Imperial Valley. The advancement of pink bollworm infestations in Arizona and Bard Valley, California, puts further emphasis on planting dates for help in control of this pest.