Photosynthetic photon efficacy (PPE) and dry weight gain per unit electric energy consumption (dry weight efficacy) for four species.

Begonia ‘Olympia Red’, geranium ‘Pinto Premium Deep Rose’, snapdragon ‘Liberty Classic Yellow’, and petunia ‘Wave Blue’ seedlings were grown for 34 d, 25 d, 24 d and 19 d, respectively, under six sole-source lighting treatments delivered from mint white (MW), red (R), blue (B), and green (G) light-emitting diodes at a total photosynthetic photon flux density (PPFD) = 160 μmol∙m−2∙s−1. The values after each LED type represent their percentages of the total PPFD.