TABLE 1.
The pH, electrical conductivity, and water temperature (mean ± standard deviation) of nutrient solutions for six lighting treatment plots in two blocks during the lettuce production phase.
| Lighting treatment | pH |
Electrical conductivity (mS⋅cm–1) |
Water temperature (°C) |
|||
| Block 1 | Block 2 | Block 1 | Block 2 | Block 1 | Block 2 | |
| WW180 | 6.0 ± 1.0 | 6.2 ± 0.9 | 1.8 ± 0.0 | 1.8 ± 0.1 | 23.7 ± 0.3 | 23.3 ± 0.3 |
| R180 | 6.1 ± 1.0 | 6.3 ± 0.9 | 1.9 ± 0.1 | 1.7 ± 0.1 | 22.9 ± 0.2 | 23.9 ± 0.4 |
| B20R160 | 6.1 ± 1.0 | 6.3 ± 0.9 | 1.9 ± 0.1 | 1.7 ± 0.1 | 22.9 ± 0.2 | 23.9 ± 0.4 |
| B20G60R100 | 6.1 ± 1.0 | 6.3 ± 0.9 | 1.9 ± 0.1 | 1.7 ± 0.1 | 22.9 ± 0.2 | 23.9 ± 0.4 |
| B20R100FR60 | 6.0 ± 1.0 | 6.2 ± 0.9 | 1.8 ± 0.0 | 1.8 ± 0.1 | 23.7 ± 0.3 | 23.3 ± 0.3 |
| B180 | 6.0 ± 1.0 | 6.2 ± 0.9 | 1.8 ± 0.0 | 1.8 ± 0.1 | 23.7 ± 0.3 | 23.3 ± 0.3 |
Plants were grown under warm-white (WW) or mixed blue (B; 400–500 nm), green (G; 500–600 nm), red (R; 600–700 nm), and far-red (FR; 700–800 nm) light-emitting diodes (LEDs). The number following each LED type is its respective photon flux density in μmol⋅m–2⋅s–1.