Amnesia Haze Auto

The trio made their way into the tent yesterday and we now sit on the eve of week 2 From seed pop. Light is at 20% 27” mid week I will bump it up to 25% and increase by 5-10% each week till we are at 90% Ive been focusing a lot of Vapor Pressure Density, Vapor Pressure Deficit measures the amount of drying power the air has upon the plant. Basically, it’s how much moisture is being sucked out of the plant by the atmosphere. You probably already know the plant uses transpiration to grow. Literally, the plant will die if it can’t release moisture through its stomata. The process of transpiration in plants is similar to how we sweat; they have stomata which are similar to our pores. But the big difference is, they do this so they can pull in more liquids through their roots to fuel photosynthesis. When Vapor Pressure Deficit is too high, the plants might not be able to keep up with the environmental demand upon them. The air is drying them out too fast! And this will cause them to exhibit symptoms that look just like nutrient deficiencies, and the plant will grow poorly. On the other end of the spectrum, if Vapor Pressure Deficit is too low the plants can’t transpire. Moisture may build up on the leaves, and the plant will grow much more slowly. If this goes unchecked for too long, the plants might get attacked by molds and fungi, like powdery mildew. Reading up on VPD you’ll see all sorts of measurements of Vapor Pressure. There’s Saturated Vapor Pressure (SVP), Atmospheric Vapor Pressure Deficit (AVPD), Leaf Vapor Pressure Deficit (LVPD), plus several others not worth mentioning. Vapor Pressure Deficit is the difference between the Saturated Vapor Pressure (SVP) and Relative Humidity. Saturated Vapor Pressure is the maximum amount of moisture the atmosphere can hold according to it’s temperature. And Relative Humidity is the amount of moisture currently suspended in the air. So to calculate the room’s Vapor Pressure Deficit all you need is two measurements, temperature and relative humidity! But this isn’t the whole story. The plant’s experience is slightly different because they are usually a bit cooler than the room. If the plant temperature is exactly the same as the room temperature, then the plant and room Vapor Pressure Deficit levels are equivalent. But this is rarely the case! Usually, the leaves are between 3° and 5° F cooler than the room because they are transpiring. The evaporation on the leaf’s surface literally draws heat from the leaf, thereby cooling it. We call this Leaf Vapor Pressure Deficit (LVPD), and we need only one more measurement to figure it out, and that’s the leaf temperature of the plants. To get this measurement we use an infrared thermometer (IR thermometer), and they are rather inexpensive, there are dozens available on Amazon for under $30. It’s so easy to take the temperature of anything with an infrared thermometer, like ballasts and reflectors. So if you’re like us, you’ll start pointing it at everything in sight. So while the room’s Vapor Pressure Deficit is important, we really want to focus on what’s going on within the plant. That means we want to know the Leaf Vapor Pressure Deficit because we’re trying to grow the best and biggest harvest possible, right? Right!