Hello every one. Ever Thought investing with a FLIR to be able to measure VPD in your garden? Can you guys talk about Pros and Cons of this idea? Im planing for pounds of buds monthly and i think FLIR can be a very effective device as growers need it to accurately calculate VPD. I'm specially interested in NebulaHaze 's idea, May i ask you to write some sentences please? What do you think?
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Last edited by Iammygod; 02-16-2017, 06:41 PM. -
What is FLIR and VPD? How is it useful? -
Controling RH and Air temperature is Traditional way to control how plants transpire. Transpiration of a plant that has a huge effect on how plant grows depends on difference between vapor pressure inside and outside of the leaf and this is what Vapor Pressure Deficit, VPD, talks about. VPD is the difference between vapor pressure inside the leaf and air vapor Pressure, the vapor pressure outside the leaf. To calculate VPD we need Leaf Surface Temperature, the parameter that can be measured precisely using a FLIR to calculate LVP as leaf can be assumed it is 100% saturated with vapor pressure at its temperature. Combination of Air Temperature and RH gaves us AVP, Air Vapor Pressure. VPD is LST minus AVP.
Saturated Vapor Pressure of each temperature is known. There is simple table of SVP everywhere although we have a mathematic formula for it.
At high VPD stomata will close to save WATER and photosynthesis ratio will decrease or even stop.
At low VPD, there is no negative pressure inside the plant to help root absorb nutrients. Leaves get warmer than ideal temperature for metabolic reactions as the plant lose its ability to cool down its leaves.
The ideal range of VPD of each stages is known.
Im planing for harvesting pounds of buds monthly. So i think it can be a good idea to buy a FLIR.Last edited by Iammygod; 02-16-2017, 08:58 PM.Comment
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It seems like a neat idea, but I'm not sure how it would be useful on a practical level as far as increasing yields. I think it would be really interesting information to know! If you could buy one for $50 i would get one just to check out the differences in my grow room! I can also see how it could be helpful diagnosing problems with airflow and temp/humidity if you're looking to dial in your grow.
You mentioned you're looking to start harvesting pounds monthly. The first step is to make sure you have enough light! That's even more important than VPD when it comes to yields. You can get about a pound per 600W HPS light (more if you have multiple 600W HPS's in the same room) per harvest by following the basics. With 1000W HPS you can expect about 1.5 pounds/light on an average grow
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I agree with Nebula. Practical is important, in most cases towards any project someone seeks, people can over exam the practicality aspects and waste time and resources.
I love the scientific aspect and rely on this knowledge during my grow. I tend to be very successful keeping a close eye on standard things like PH and temps.
I harvest a pound every 2 months, staying practical! BUT, learning about new techniques and readings from instruments, can be beneficial. Here is a sample from last weeks harvest...Current Grow #16: White Widow Germinated Jan 2019
10x10 Laboratory
FloraNova in Recirculating Hydro
T5HO White/Blue for Veg - 600 HPS + T5HO Red for flowerComment
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Thanks for replying Nebula.
You may know I'm a new grower. For you as experienced grower, you know how to react with your light intensity, air humidity and temperature. Moreover you are using HID light. This kind of lights are being used for decades and there is lots of information about them. Combination of these information and your experience are what you use to reach to great results. But to me it's different and I'm still interested in LEDs. Who can say what the ideal environment parameters are under LEDs? There are only 2-3 technologies of HID but each LED models is a new technology designed by a company and need different environment conditions if you agree with me. Plus if we can measure parameters for few dollars that controls how plants grow why dont we have to pay these dollars? RT and AT have huge effect on growth? Why? Is it because of transpiration and RT and AT control transpiration? How accurate do we can adjust transpiration using this kind of data for veg:
Temp: 20-30°c
RT: 40-70%
But VPD tells us how much transpiration take place much precisely. 2 things I'm going to highlight:
1. The difference between 40% and 70% is huge. Try to cure your buds at 30% below or higher than ideal RT and see the differences(I've never cured any buds before but i know it has to be huge difference at least on how fast buds evaporate water. At higher temperature this difference between 40% and 70% will be much more)
2. 40-70% can be use at 20-30 temperature ONLY for HIDs Not LEDs(because of no standardization of LEDs it may good range for LEDs that use white diodes either). HIDs trun 30% of light to useless photons that just warp up leaves with no photosynthesis. Well-designed LEDs eliminate this emissions so they need warmer air temp to achieved ideal Leaf Surfaces Temperature as metabolic reactions take place in a narrow band of temperature range. So not 20-30°c and not 40-70% RH are ideal for LEDs.
I think even if a grower trys to stay at this range she/he still is outside of the range of ideal transpiration much of time. There is unbelievable differences in transpiration between these below 2 conditions although they both seem to be at range(try to dry a cloth at each)
● T:21°c,RT:65%
● T:29°c,RT:45%
An IR thermometer allows the grower to measure LST and LST is fortunately independent from spectrum and intensity of light resource. when LST is at it ideal renge we see metabolic reactions take place much faster. Combination of LST with RT and AT measured by a hygrometer can be used to calculate and adjust VPD. The more you belive in temp, RH and specially light intensity importance, the more the important VPD is accordingly
I think we all have to have an IR thermometer. I had read an article by Siri(did i write his name correctly?) he said he was tring to give more light to his plants without heat stress by giving his plants low temperature to be able to move light closer. We all know what happened after that. But why? To me it's VPD and LST. even at very cool temperature plants LST can go higher than its ideal by to much light(lol i still have no idea why LEDs light burning or heat stress take place. I also dont know what kind of diodes those LEDs had. white diodes like HIDs light have high percentage of usefulness photons).
Measuring and adjust VPD is not much complicated. It doesn't need much expensive devices to take a measurement. It takes light intensity into the account and i think VPD is much important than a simple number. I belive measuring VPD is much important for growers that use LED than those who use HID because of no standardization of LEDs.
Yeah pounds of buds. What is the difference between price of 600w and 1000w HID? 50 dollars? But It Takes me about 1000 dollars if i buy my favorite 1000w LED model instead of 600 watt.
VPD has low effect on yield for sure. But it has huge effect on growth rate. I belive LED growers who knows 4 simple numbers, an IR thermometer and how it should be used can take better advantage of their light and this doesn't mean tha HID growers should forget measuring VPD.
Now What? What Do you think about investing with an IR Thermometer or an FLIR camera? it worths? In which condition do it worth?
Pounds of buds can be easily achieved by 2730 watt PGS of Phytomax-2 (lol i really like LEDs) in a 5'×9' flowering tent and a perpetual harvest.Last edited by Iammygod; 02-18-2017, 11:27 AM.Comment
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I check this topic several times everyday for a new reply 😶
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