"High‑light" crops are the ones that reward you when you keep PAR high: fruiting crops, vigorous berries, many herbs, and dense canopies that shade themselves quickly. In these houses, the goal is simple: lose as little sunlight as possible at the cover—then manage heat and humidity with ventilation and good hardware.
Clear greenhouse plastic is usually the best starting point because it offers the highest transmission. If you're in a hot climate, you don't "fix" heat with a low‑transmission cover—you fix it with venting, shade strategies, and irrigation timing, so you don't starve the crop for light.