How Vapor Pressure Deficit Impacts Cannabis Plants

>> YOUR LINK HERE: ___ http://youtube.com/watch?v=DLUCdBJkJ6k

How Vapor Pressure Deficit Impacts Cannabis Plants • Professor DeBacco • • Vapor Pressure Deficit (VPD) • This is an advanced method for understanding and measuring the indoor (or technically outdoor) growing environment. • Outdoor it is more for monitoring • Indoor growers can calculate VPD and then made changes to the conditions • It does require more equipment to gather information and an understanding of the overall growing environment which is why this is considered to be a more advanced technique. • • Equipment Needed • Thermometer • Used to measure the air temperature • Hygrometer • Allows the humidity to be measured • IR thermometer • Provides the temperature of the leaf • With the data generated you can calculate the VPD of the growing space. • • VPD Takes Into Account Entire Environment • This allows a consistent measure that takes into account the three main variables in a grow space. • • What VPD Influences • Transpiration • As VPD increases, the plant transpires faster • Stomata Opening • As VPD increases, stomata get smaller. • CO2 uptake • As VPD increases and stomata get smaller, CO2 uptake gets reduced. • Nutrient intake at the roots • Increasing VPD and transpiration rates will mean the roots pull in more nutrients. • Plant stress • Increasing VPD = Increased plant stress • VPD Chart • • Vapor Pressure Conversion Factors • The most common unit of measure for growers is kilopascals (kPa), however inches of Mercury (in Hg) can also be used. • • Some Suggested Target VPD by Growth Phase • Propagation and early Veg: • 0.2 – 0.8 kPa • Late veg and early Flower: • 0.8 – 1.4 kPa • Mid-flower to late Flower: • 1.2 – 1.5 kPa • How Environment Impacts VPD • Temperature • Increase temperature : Increase VPD • Decrease temperature : Decrease VPD • Humidity • Increase humidity : Decrease VPD • Decrease humidity : Increase VPD • Light Intensity • Increase light intensity : increase leaf temps = Increase VPD • Decrease light intensity : decrease leaf temps = Decrease VPD • • Relative Humidity at Given Temperatures and VPDs • Suggested values are for required to maintain ideal growing conditions. • This is the lights on • • Transpiration = Water Movement in Plants • Water first enters the roots of a plant and will travel through the plant and exit out small regulated pores called stomata. • This general movement of water is called transpiration is it allows for nutrients to move through the plant and also is a method of cooling the plant. • The humidity is considered to be around 100% inside a healthy leaf. • This represents saturated vapor pressure • Transpiration Rates • Transpiration rates will be faster in hot and dry conditions • Rates will slow in high humid because the water has no where to evaporate to. • The stomata need to be regulated because when they are open they can let CO2 in for photosynthesis but at the same time the plant is loosing water. • Plants need to balance out the ability to photosynthesize and remain hydrated. • • • Link to Lecture Slides: https://drive.google.com/file/d/1GfAU... • *Due to the description character limit the full work cited for How Vapor Pressure Deficit Impacts Cannabis Plants can be viewed at... https://drive.google.com/file/d/1h1BG...

#############################

New on site