Environment Conditions

[DrPhoton]

Removed for security reasons

[Campesino]

Thanks DrPhoton
Thoughts on these VPD charts?

http://www.just4growers.com/media/23631/vpd_2degree.gif

http://www.just4growers.com/media/23637/vpd_1degree.gif

[DrPhoton]

Just4growers is a good source, love watching his videos.

Temperature is the key reason RH is not as accurate for water loss in plants, as RH does not measure pressure difference. It measures capacity percentages.

The potential for transpiration will be different with 50% RH at 75°F compared to 50% RH at 83°F. Even though the relative humidity is unchanged, the temperature effects change the potential of fluid movement.

However, relative humidity can be used for a narrow range of temperatures. Outside a set temperature range and the RH can be thrown out the door. Saying that, you are expected to grow within a recommended range of temperatures for optimal efficiency, so the recommended RH ranges can be reliable.

I am going to update the recommended ranges for different stages of growth.

[Paracelsus]

Thanks Dan, I especially enjoyed reading your humidity tutorial section because I happen to use towels hanging around my young plants saturated with hot water and wrung out out that I change every 6 hours or so to keep humidity high in these dry winter months. It does create it own micro climate.

I read in the comments section of your article on light diffusion and intensity someone who wished to share your info. I read your reply and I understand you wanting to concentrate your efforts here at GWB. But I would encourage you to take a look at Tim Wilson’s forum called www.LogicalGardener.org

The focus there is more academic and scholarly there is not much traffic but the content and overall focus on things to do with living organic soil is full of very valuable information

[DrPhoton]

Interesting, but yes i really only want to put my time into one area. Im not entirely worried about the reception of my work, i do it for myself also to asses my own understanding. Also this place is young, so maybe over time my information can transcend and become a more factually correct community compared to other forums.

One thing i am really behind on is my soil science, i really want to put some time into this. Unfurtunately books on plant biology, physiology or botany. Dont focus heavily on soil. So i think in order to develop my understanding further, i must pick up a book dedicated to soil biology.

[Paracelsus]

Well I can certainly recommend Teeming with Microbes by Jeff Lowenfels and Wayne Lewis which is available online from many libraries. Lowenfels has a series of books on the topic. Mycelium Running: How Mushrooms Can Help Save the World is the sixth book written by American mycologist Paul Stamets. Both authors have numerous videos on YT, including TED TALKS There are quite a few threads on other sites that have enlightened me greatly.
If I had to pick one as the most authoritative with practical how to applications and guidence it would be No Till Gardening: Revisited on the Grass City Forum. https://forum.grasscity.com/threads/...sited.1400505/

[DrPhoton]

Il definately have a look, thanks para.

[Weed Pharma]

Great information!
Environment is most important and far too many growers overlook this, by turning to the bottle to increase crops.

I have grown several plants staying within the above VPD guuidelines- I can vouch that the plants grew much better and looked great.
I can also say, that the outcome in yield/quality was not changed significantly-especially when compared to the time/money involved.

In fact, this led me to do a grow under conditions most would worry/stress over- and in a few days we will get the results on a cold/very low humidity grow!

https://forum.growweedeasy.com/forum/growing-community/167838-kiss-grow-fastbuds-girl-scout-cookies-autoflower

[DrPhoton]

Awesome, good to know. I actually have not used VPD myself.

[desertdan]

Was the chandra study done indoors or outdoors? From observation and experience this is not the case for outdoor. Similar but the temp ranges could be larger. As I have not kept any logs on temp and growth rates I can not be sure but from my experience and observations outdoor grown plants do well in a greater temp range than indoor. My plants seem to grow best when daytime is upper 90s and nights mid 70s.

[DrPhoton]

Of course certain genetics handle environments differently and there is also the aspect of environmental conditioning through phenotypic adaptation. Chandra had follow up studies to asses the genetic aspect of this variable. Which he found similar conclusions with most strains, but definitely found some strains could handle a higher temperature. But he still showed that the ideal temperature range was between 75°F to 83°F. As the strains that could handle up to 95°F, had negative effects in other aspects such as stomatal conductance and respiration.

With my experience outdoors, many strains are negatively affected with temperatures higher than 90°F. Although some do thrive happily up to 95°F

Typically the higher the temperature the higher the photosynthetic efficiency until a certain point. I do agree with you that yes, outdoors does appear to handle a wider range of temperatures. But ultimately we are concerned with the most effective and efficient range.

[Paracelsus]

Great information!
Environment is most important!

In fact, this led me to do a grow under conditions most would worry/stress over- and in a few days we will get the results on a cold/very low humidity grow!

Please let me know how that comes out because I’m not sure about my humidity range Fluctuation all over the place.

[Weed Pharma]

Paracelsus, results: https://forum.growweedeasy.com/forum...toflower/page2

[PaganRich]

DrPhoton Great article mate but I have one question which I`m sure you`ve already answered but I`ve missed....Dark strains need a drop in temp to help the dark/ purple colours develop. Does this occur due to temp drop or is the lack of light another contributing factor?

[PaganRich]

Paracelsus Did that not shock the roots?

[Paracelsus]

Yes but that’s one method

[PaganRich]

Paracelsus Interesting bit of info. Thank you for that, mate.

[DrPhoton]

Improved readability and added further information.