Required PPFD (µMol m⁻²s⁻¹)	Type of Lamp	Annual Irradiance Period	Irradiance per Day	Purpose and Method
stock plants: 40-55	HID	WINter	16 hrs (incl. daylight)	Improving vegetative growth.
cuttings: 1-1.5	TL	WINter	16 hrs (incl. daylight)	Flower deferment.
pot plants: 45-55	HID	WINter	16 hrs (incl. daylight)	Improving vegetative growth, shorter culture time.

PPFD for different Lamp types

The recommended irradiation level is expressed in µmol m⁻²s⁻¹ (PPFD). However, in practice, the irradiation unit lux is often still used. Therefore, the conversion from lux to PPFD is shown below. This conversion is not a constant but is dependent on light source, operating temperature, and amount of operating hours of the lamp.

• inc. - incandescent; 1000 lux is approx. 18 µmol m⁻²s⁻¹


• PL - PLE (compact fluorescent lamp); 1000 lux is approx. 13-14 µmol m⁻²s⁻¹


• TL - tubular fluorescent lamp; 1000 lux is approx. 13-14 µmol m⁻²s⁻¹


• HID - high-intensity discharge lamp (MASTER GreenPower, MASTER Agro or HPI-T Plus); 1000 lux is approx. 12-13 µmol m⁻²s⁻¹


• LED Please Vist Lux to LED PAR (PPFD) Calculator