Fig. 1. Effect of photosynthetic photon flux density (PPFD) and red:far-red ratio (R:FR) on stem and total plant weight of redroot pigweed under 12- and 16-h daylengths. Statistical analysis is provided in Table 5. DAE = days after emergence; HH = high PPFD and high R:FR ratio; LH = low PPFD and high R:FR ratio; LL = low PPFD and low R:FR ratio.