Tab. 1: Used fertilizer mixture for strawberries

Tab. 1: Used fertilizer mixture for strawberries.

Fertilizer (amount in kg) (amount in l) * (amount in g) ** Stem solution A (100 l)

Calciumnitrate Iron 6 %* DTPA * Iron 6 % EDDHA ** Potassium sulfate Magnesium sulfate Monopotassium phosphate Potassium nitrate Mangansulfat 32,5 % Mn ** Borax 11,3 % B ** Koparsulfat 24 % Cu ** Zinksulfat 23 % Zn ** Natriummolybdat 40 % Mo **

–––––– Stem solution B ––––––(100 l) Relation

Planting – 10 white fruits / plant (growth) 10 white fruits / plant – harvest end (fruit development)

8,4 0,2 50 1,3 3,6 1,7 2,9 51 14 3 21 1,5 1:100

7,3

(without NH4+) 0,25 50 1,3 3,6 1,7 7,3 51 14 3 21 1,5 1:100

3.2 Treatments

Strawberries were grown from 01.10.2018-14.01.2019 in two chambers with different light sources:

1. HPS top lighting (Philips bulbs, 600 W) 180 W/m2, 269 µmol/m2/s, HPS 16 °C 2. LED top lighting (GreenPower LED, Philips), 278 µmol/m2/s µmol, LED 19 °C

Lamps for top lighting were mounted horizontally over the canopy. Light was provided for 16 hours (07.00-23.00). Half of the lamps went on at 07.00 and the other half at 07.30. Half of the lamps went off at 23.00 and the other half at 23.30. The lamps were automatically turned off when incoming illuminance was above the desired set-point. The lamps were distributed in the way that strawberries got the most equal light distribution, on average 269 µmol/m2/s in the HPS chamber and 278 µmol/m2/s in the LED chamber (Tab. 2). In addition, white plastic on the surrounding walls helped to get a higher light level at the edges of the growing area.