“Climate control under artificial light” By André Kool, consultant Green Q 10 February 2010

“Climate control under artificial light” By André Kool, consultant Green Q 10 February 2010

HPS-lights+LED (Komeett, IC) TEKST

HPS-lights+LED (Komeett, IC)

LED-lights = growth pipe? TEKST

Curly leaves near LED sugar accumulation? TEKST

Botrytis

Leaf tips in tomatoesweak plantcell walls

Weak plant cell wallshigh humidity less Ca in cell wallweak root pressure, (sudden) evaporationcell wall burst

Weak plant cell walls

Botrytis hits damaged leafs……

…..and finally stem botrytis

Humidity rims in cucumber

Artificial light  crops evaporates Ca uptake by leaves Ca = required for strong cell walls Too high humiditycrop evoporates loo lesstoo less Ca in leaves too less Ca in plant cell wall “Shocks” in humidity and /or root pressure cell wall burst leaf rims > X hours Y % air humidity = botrytis Problems related to artificial light

For uptake of Ca in leaves create evaporation during hours of lighting  HD >3 (3.0-6.0) Avoid extreme high greenhouse air humidities: pre-night not <1.5, but certainly not < 1.0 after-night 1.5-2.5, preferably >2.0 morning 2.5-3.0 afternoon peak 3.0-5.0 (tomatoes 4.0-6.0) Prevention / solution

Create sufficient air movement en evaporation by: (Growth) pipe > 20°C warmer than surrounding air. Careful ventilation during cold weather (frost) and lights on no cold air falling down on heads blocks evaporationproblems……… Try to ventilate with small % at lee-side even at (heavy) frost at artificial light and high greenhouse humidity Feel if windows are not frozen to construction In Finland small ventilation % at -16°C (no wind). Small % (1-2%) is enough too get rid of humidity more =risk of cold heads Prevention / solution

Questions?

Thanks for your attention! www.greenq.nl

“Climate control under artificial light” By André Kool, consultant Green Q 10 February 2010