Following The Grow Boss tips on YouTube "...yield is based on light, quality is based on growers talent" "...number one problem is, too much light, too much water, too many nutrients" Nutrients : (after having issues with nut burns, I decided to use Grow Boss's perfect ppm calculator) Invasion T (Glomus intraradices BEG72 and TRICHODERMA atrovide MUCL45632) 1g / plant Monster X mycorhizes (500 000 propaguls / Kg , made in vitro) 2g / 20cl then complete to make 1l Humic Fulvic Booster (humic and fulvic acids) 1ml / 1l Cannazym 2.5ml / 1l Rhizoponics 0.4ml/1l Lights: 2 x Adjust-A-Wings Avenger 600w HPS Lumatek 90000 Lumens 1000PAR 600w HPS Philips Son-t Green Power 95000 Lumens Soil:Platinium Royal Mix premium quality What is vapor pressure deficit? Often, marijuana growers who have their plants in indoor grow tents or rooms with artificial lighting, take into account parameters such as temperature and relative humidity to maximize plants growth and bloom, thus obtaining abundant harvest with top quality flowers. As we will see later, these factors affect different processes of the plant, such as transpiration or nutrient uptake. However, we usually forget about another important factor that is related to the aforementioned ones: vapor pressure deficit or VPD. Broadly speaking, VPD is the difference between the amount of water vapor that the atmosphere is able to retain (which depends on temperature) and the amount of water vapor contained in it (relative humidity). It is usually measured in kilopascals (kPa). Providing our plants with a correct relationship between temperature and relative moisture will keep us on the right VPD parameters, increasing the plant’s activity and thus improving its growth and showing its full potential during the flowering phase. The ideal would be to adjust both parameters (temperature and humidity) to get the best possible VPD value, so that the development of plants will be amazing.In the chart above you can see the right temperature and moisture values to maximize the development of cannabis plants. The green zone shows you optimal values of VPD, in which it would be ideal to maintain the environment. The orange zone shows correct values, in which plants should not have problems to develop normally. However, red areas show values in which your plants will be very far from hit their full potential, since the relation between temperature and moisture is not optimal. With relatively high values of VPD (between 5 and 12) plants tend to open their stomata and release a considerable amount of water vapor into the environment (increasing their transpiration). This increase in transpiration results in an increase in the plant’s photosynthetic activity, which will need more nutrients and will improve its overall growth, both during growth and bloom. The best range is between 7.5 and 10.5, which we have marked in green. However, we must be careful that VPD is not too high (dark red zone) since the plant would close its stomata to avoid releasing too much water vapor to the environment, which would result in fast dehydration due to excessive transpiration. On the other hand, if VPD is too low (light red zone), the plant will also close its stomata for not releasing more water into the atmosphere, which in this case would be already saturated (it would have reached the maximum water retention capacity in a specific temperature). In this way, reducing transpiration will also reduce photosynthesis, which has a direct impact on the plant’s development and yield. That way, VPD is essential when it comes to offer the best conditions for the development of plants, also to understand its water requirements according to the nutrients used and thus adjust them correctly to meet the grower’s expectations. N/B: SAY NO TO DRUGS -[Day 90] The plants are getting massive, not a lot of space left in the room, each pictures are token back against the wall or on top of a chair. The Super Skunk shall be ready first , the trichomes are visible without using a microscope, the scent is like an amazing candy floss coated with Skunk pee 😅Boerejongens quality @Home 😊 -[Day 93] Switching Buld Lumatek 90000 Lumens 1000PAR to SuperPlant Super Red 85000 Lumens 2000K 1498nm Lightening under the 1500nm wavelength (2000K) just between the NIR and the Microwave length, can't stand in the room too long without getting tears and shining eyes. Buds shall start to blowup like pineapples, increasing yield. -[Day 98] Everything is getting frosty. Starting to decrease RH .