Anyone else find the back plants do better?

[RoyC]

I normally have 9 plants in a 1.2x 1.2x 2m tent and the back 3 plants are always better. They grow taller, produce bigger yield and are more healthy and the people I know get the same thing, does anyone have the same issue or know why this is? My best guess is when tent doors are unzipped during watering ect the front plants get that little bit less side reflection from the tent doors reflection not being there for a hour here and there and over the cycle it would add up so I'm going to put dimond silver mylar up on the wall behind me adjacent to the tent doors to see if that's the solution but if anyone knows would be much appreciated, cheers
@oldsalt

 

[Sativa1970]

There is something in the environment going unnoticed. I don't think it is the light not bouncing off the open door. Bounced light is a fraction of the DLI. 25% of the square root of the total distance light travels x the time the door is open subtracted from DLI. If the door is open for an hour a day those front plant may loose 3wats for every 300wats they would get in 12 hours. An insignificant loss of light.

Is the light centered and level?
All being watered the same?
Fan circulating air equally over the plant tops?
Fresh air intake/exhaust favoring a side?
Is the back wall up against a house wall effecting the wall temp?

 

[Sparkey224]

My back two plants are always bigger then 2 up front. My light is centered and level.
2 strains both clones.
@Greenvein and I were just talking about this.
Can't figure it out. Probably mess too much with the 2 up front..

 

[Sparkey224]

There is something in the environment going unnoticed. I don't think it is the light not bouncing off the open door. Bounced light is a fraction of the DLI. 25% of the square root of the total distance light travels x the time the door is open subtracted from DLI. If the door is open for an hour a day those front plant may loose 3wats for every 300wats they would get in 12 hours. An insignificant loss of light.

Is the light centered and level?
All being watered the same?
Fan circulating air equally over the plant tops?
Fresh air intake/exhaust favoring a side?
Is the back wall up against a house wall effecting the wall temp?

Makes a lot of sense

 

[Greenvein]

My back two plants are always bigger then 2 up front. My light is centered and level.
2 strains both clones.
@Greenvein and I were just talking about this.
Can't figure it out. Probably mess too much with the 2 up front..

Looks like they all noticing it..
it could be my door opening although I don't have to open my tent daily as I auto feed from outside the tent. I could throw a camera in to reduce this and test it
I think it's to do with my intake being a window on the lower right side of my tent then exhaust being at the back right. all my fans are at the front blowing towards the back.. I need to put my electricity at the back and blow the air forward so it has to circulate before it's pulled out.

 

[SmokingWings]

Interesting. I have noticed in some of the photos that have been posted that others have the same thing happening. Their plants at the back of the tent do look taller and often look greener.

I don't think it is the light not bouncing off the open door.

The amount of reflected light is minimal as you mentioned. I open the tent door when the lights come on and close the door when the lights are off. I am using the heat from the lights to help balance the temperature in both the tent and in the growing room.

In my case the better plants, the ones with more and larger flower buds & more and larger leaves are the ones closer to the door.

 

[Sativa1970]

If everything else appears equal I would look outside the tent. The back wall is going to near a house wall in most cases I would think. The wall would be a heat sink. That could be good or bad depending on your environment. SmokingWings, is your back wall against a cold exterior wall? If the back wall plants grow better is it up against a warm interior wall?

 

[RoyC]

There is something in the environment going unnoticed. I don't think it is the light not bouncing off the open door. Bounced light is a fraction of the DLI. 25% of the square root of the total distance light travels x the time the door is open subtracted from DLI. If the door is open for an hour a day those front plant may loose 3wats for every 300wats they would get in 12 hours. An insignificant loss of light.

Is the light centered and level?
All being watered the same?
Fan circulating air equally over the plant tops?
Fresh air intake/exhaust favoring a side?
Is the back wall up against a house wall effecting the wall temp?

Hi thanks for the reply, the light has a little spirit level I put on it I frequently check, I do water from back through to the front which may have an influence by water temp dropping, nutrient concentrated on bottom of bucket ect? two fans left and right sides lots of air flow, no sides are touching walls but back and left are close, air intake from right side and in summer right, left and back are open, the carbon fiber extraction is at the top back and is something that most people do probably so was curious about that to, has anyone out there got extractor on font side? I've been trying to work this problem out for awhile and the reflection was the only thing I thought could be most influential until smoking wing blew that theory out, do you have reflective or white walls in room adjacent to tent doors? The only other thing I thought was I tend to tinker around with the front ones more removing leaves shadowing buds ect. I'm going to get that dimond mylar and line outside tent door wall soon I think anyway and will let you's know, the photo doesn't really show but put it on anyway, thank for the help would really like to get this issue sorted if I could get them all like the back it would be mint cheers

 

[bluter]

temp and handling differences would account for most of it. it won't happen if you rotate your plants or remove them to feed or work on them,

 

[Sativa1970]

I do water from back through to the front which may have an influence by water temp dropping, nutrient concentrated on bottom of bucket ect?

What system are you running where the water parameters can change from back to front plants? Or... Are you saying that your "watering can" may be changing the parameters as you pour?

I think you spotted the difference already. You prune the easy to reach more than the hard to reach plants. Young leaves are more efficient at making food but mature leaves are more efficient at storing readily available food. Those mature leaves feed the growth at night while the young leaves reset and rest for tomorrows production.

 

[SmokingWings]

SmokingWings, is your back wall against a cold exterior wall? If the back wall plants grow better is it up against a warm interior wall?

Nope, it is about 4 inches from the wall which is an interior wall. And the one side wall on my left as I look in is about 6 inches away from an outside wall but that wall does face south. The first couple of inches of soil on the other side rarely freezes unless the outdoor temperatures drop down close to 10F or lower for more than several days.

I figure the reason that the plants near the tent door do better is that the ones that I think will produce average quality and quantity get moved to the back. The ones that I believe will be better than average get moved to the front so I can keep track of what is happening to them and how they react.

About a year ago I had noticed that the ones near the tent door were doing better and when the thread topic turned up it got me wondering why.

 

[RoyC]

Could there be a temp difference from front to back of tent?
I rotate them putting the slower ones to the back to catch up in veg until flower, cant really move them after strech, they get damaged because I try to train them to have a tight evan canopy.
With watering I was just throwing ideas out the that could have differences, i just use aquarium pump in bucket with lance sprayer, just thought coz I water back ones first and the pump sucks from bottom maybe after mixing nutrients they slowly settle to the bottom slightly concentrated
I've been trying to rack my brain for along time now but can figure this one out so thought I'd ask, so no one thinks it could be reflection? That was my best bet

 

[Greenvein]

Could there be a temp difference from front to back of tent?
I rotate them putting the slower ones to the back to catch up in veg until flower, cant really move them after strech, they get damaged because I try to train them to have a tight evan canopy.
With watering I was just throwing ideas out the that could have differences, i just use aquarium pump in bucket with lance sprayer, just thought coz I water back ones first and the pump sucks from bottom maybe after mixing nutrients they slowly settle to the bottom slightly concentrated
I've been trying to rack my brain for along time now but can figure this one out so thought I'd ask, so no one thinks it could be reflection? That was my best bet

Mine are auto fed with drippers so all get same food at the same time.. for me I think it's definitely due to my air circulation.. the corner getting the lowest air exchange no fresh co2. I'll be breaking my intake to exhaust path as much as possible next round pushing everything to the front first.

 

[Sativa1970]

A room full of people could all agree that there is an optimum and suboptimal location in there grow space. The location and reason could be different for every one of them. Solution for the first persons issue will not necessarily work on the second persons issue. It could be any one (or multiple) of 10 or more parameters that are not optimized as much here as there. Fine tuning is the craft of this hobby.

Light
Air temp
root temp
humidity
air circulation
CO2 level
root zone moisture
root zone O2
nutrients
Pruning practice

 

[Trump]

A room full of people could all agree that there is an optimum and suboptimal location in there grow space. The location and reason could be different for every one of them. Solution for the first persons issue will not necessarily work on the second persons issue. It could be any one (or multiple) of 10 or more parameters that are not optimized as much here as there. Fine tuning is the craft of this hobby.

Light
Air temp
root temp
humidity
air circulation
CO2 level
root zone moisture
root zone O2
nutrients
Pruning practice

Agreed. Could be many things. My guess would be that the environment doesn't change quite as much and quite as quickly as it does near the door. I only open my tents to either work on the girls or if it's getting too hot inside.

You can test this out the next time you do a run by taking readings from your hygrometer in different parts of the room. Ideally if you had several that were calibrated equally it would be more precise as the conditions will change going from one reading to the other if you only use one hygrometer and you really want to get a reading of that moment and where each area is as far as temp/humidity but if you really want to find out what's going on that would be the way to start quantifying actionable data.

It could be that more air circulation is happening back there changing the VPD in that area to a more favorable condition but I'm just stabbing in the dark now.

On this next run I'll be switching up a few things as far as air flow in the tent. I'm currently running separate COB boards. They work great but I grow using ScrOG so a bar style light would be better for more even coverage over the entire canopy. I'll be switching out my COB boards for a bar style light. Instead of running oscillating fans to move air across the canopy I'm going to hang a box fan above the bar light, pointed at the roof. Box fans are cheap, last long and pull a lot of CFM. The reasoning behind this is to create an airstream with the box fan that will pull air from the inlet flaps at the bottom of the tent, through the canopy pulling whatever transpiration and gasses the plants have expulsed into the immediate canopy area up through the lights, cooling them and towards the roof of the tent where I will setup my exhaust fan to exhaust out the window.

Underneath the canopy I can setup the four AC Infinity New gen oscillating fans they just sent me as replacements or set up a few stationary Honeywell Turboforce fans. While air circulation under the canopy will result from either setup, my aim isn't so much to circulate the air under the canopy as it is to push air through the cloth bags to gain whatever type of enrichment the extra O² is providing the root system. It'll create dry spots in the media if air is being directed at the pots themselves but I can do more frequent waterings with less volume to keep those areas hydrated along with whatever capillary action keeping that part of the soil moist.

This last run I setup one Turboforce fan underneath to circulate air under the canopy and I noticed that the flowers that were growing near that fan seemed to really bulk up. I want to see if it was the extra O² the fans were providing to the root zone that made that difference. Coincidentally the fan was placed at the back wall of the tent!

Would love to hear where I'm flawed in my plan!!!

 

[Sativa1970]

Agreed. Could be many things. My guess would be that the environment doesn't change quite as much and quite as quickly as it does near the door. I only open my tents to either work on the girls or if it's getting too hot inside.

You can test this out the next time you do a run by taking readings from your hygrometer in different parts of the room. Ideally if you had several that were calibrated equally it would be more precise as the conditions will change going from one reading to the other if you only use one hygrometer and you really want to get a reading of that moment and where each area is as far as temp/humidity but if you really want to find out what's going on that would be the way to start quantifying actionable data.

It could be that more air circulation is happening back there changing the VPD in that area to a more favorable condition but I'm just stabbing in the dark now.

On this next run I'll be switching up a few things as far as air flow in the tent. I'm currently running separate COB boards. They work great but I grow using ScrOG so a bar style light would be better for more even coverage over the entire canopy. I'll be switching out my COB boards for a bar style light. Instead of running oscillating fans to move air across the canopy I'm going to hang a box fan above the bar light, pointed at the roof. Box fans are cheap, last long and pull a lot of CFM. The reasoning behind this is to create an airstream with the box fan that will pull air from the inlet flaps at the bottom of the tent, through the canopy pulling whatever transpiration and gasses the plants have expulsed into the immediate canopy area up through the lights, cooling them and towards the roof of the tent where I will setup my exhaust fan to exhaust out the window.

Underneath the canopy I can setup the four AC Infinity New gen oscillating fans they just sent me as replacements or set up a few stationary Honeywell Turboforce fans. While air circulation under the canopy will result from either setup, my aim isn't so much to circulate the air under the canopy as it is to push air through the cloth bags to gain whatever type of enrichment the extra O² is providing the root system. It'll create dry spots in the media if air is being directed at the pots themselves but I can do more frequent waterings with less volume to keep those areas hydrated along with whatever capillary action keeping that part of the soil moist.

This last run I setup one Turboforce fan underneath to circulate air under the canopy and I noticed that the flowers that were growing near that fan seemed to really bulk up. I want to see if it was the extra O² the fans were providing to the root zone that made that difference. Coincidentally the fan was placed at the back wall of the tent!

Would love to hear where I'm flawed in my plan!!!

I run oscillating fans down low that push air up through the canopy and multiple smaller lights for a more even coverage. I was getting a few rely good buds, few light burn spots and a bunch of ok buds before those changes. Both of those changes made a noticeable difference in the canopy consistency.

I did this change when I was still using a drain to waste system. The increased air flow over the exposed media and the plants being more photoactive drove my RH way up. I have a larger boost exhaust fan that kicks on only if the room gets too hot. I added a dehumidistat switch so it would also kicked on with high humidity. The humidistat hasn't kicked on since switching to DWC so the media was the major contributor. Just something to keep an eye on.

 

[Absorber]

I had the opposite with my 2 tents and I didn't think about it too much as I had 4 different strains in each tent so no benchmark. But my front ones are bigger

 

[Greenvein]

I had the opposite with my 2 tents and I didn't think about it too much as I had 4 different strains in each tent so no benchmark. But my front ones are bigger

Bruh if your front ones are bigger where is your intake and exhaust?

 

[Absorber]

Bruh if your front ones are bigger where is your intake and exhaust?

The intake is at the back bottom and the exhaust is top middle

 

[Greenvein]

The intake is at the back bottom and the exhaust is top middle

Bang bang he shot me down bang bang cheers probably just different for everyone could be so many things but I'm definitely changing my air flow up