Heat control?

[Charmanderrr]

It’s very hot where I live. My garden stays around 85 degrees and I feel it’s time to do something since they’re budding now.
how can I drop the temps a bit? I’d like to be under 80 at least. Any methods I can try for a closet grow?

I should add I’m using 2 85w led lights so they aren’t very hot. I have 3 fans in a 2x4x5

 

[Paul Squiggle]

Hi mate. Just extraction to draw the heat out, a small AC unit or swamp cooler. Or a 5ltr bottle of water, frozen and placed in front of a fan, but have it raised above the canopy, as the cooler air sinks.

I always keep one ready, just incase we get a hot day..

 

[copperrein]

85 isn't terrible depending on your humidity but airflow is key, like @Squiggle said. If you fancy some brain abuse, google VPD (vapor pressure deficit). It's the difference between two measurements: how much moisture the air can POTENTIALLY hold...and how much it's currently holding.

Ignore the three color bars I added...those were my VPD values a week or so ago (not good, killed a sprout)

You want to try to stay as green as possible. Don't freak out when you google VPD, it's a lot of nerdy shit but once you can sort of visualize what's going on in a plant when the VPD goes up or down, you'll start to understand the whole realm of growing better.

 

[Just A Simple Guy]

My grow is in the closet of a spare bedroom. I run a window A/C and decent size dehumidifier in the bedroom and an inline fan in the closet venting into the unfinished attic plus a good tower fan to circulate air. I'm currently running a 220W LED at 92% and my grow room temp is roughly 7F higher than room temp during lights on.

Concerning VPD here's what I use. I don't really chase VPD but use it to ensure I'm not wildly outside the optimal range. For this formula you need to be able to get an accurate leaf surface temperature. My current VPD runs between 1.2 & 1.3.

HOW TO CALCULATE YOUR OWN VPD:

If you don't like math your in luck here is a formula you can put into a spreadsheet to do it for you. I use excel personally and check the value against a chart like in the above post.

Enter the formula on the next line into spreadsheet cell A10 (copy and paste it).

=3.386*(EXP(17.863-9621/(A7+460))-((A6/100)*EXP(17.863-9621/(A5+460))))

You will type-in 3 values into 3 other cells:

• Cell A5: The air temperature (A5 in the formula)
• Cell A6: The air %RH (A6 in the formula)
• Cell A7: The leaf temperature (A7 in the formula)

Cell A10 will then give you the total VPD for that grow room condition.

 

[sneekymofo]

It’s very hot where I live. My garden stays around 85 degrees and I feel it’s time to do something since they’re budding now.
how can I drop the temps a bit? I’d like to be under 80 at least. Any methods I can try for a closet grow?

I should add I’m using 2 85w led lights so they aren’t very hot. I have 3 fans in a 2x4x5

This is a long shot, but I got lucky on my first closet grow. By cutting a hole in the wall I could draw cold air from a cooler location (a basement) and force cooler air in through the walls. If you don’t have a source in your location of cooler air, it’s water bottles and A/C units unfortunately. I do everything I can to avoid adding, since adding adds moving parts. For instance, A/C will change humidity in the room, now you need a dehumidifier, etc. but sometimes that’s the only option. I would just say make sure the source of the air is as cold as you can make it. Sometimes a well-placed fan is all that’s needed….good luck!

 

[Charmanderrr]

85 isn't terrible depending on your humidity but airflow is key, like @Squiggle said. If you fancy some brain abuse, google VPD (vapor pressure deficit). It's the difference between two measurements: how much moisture the air can POTENTIALLY hold...and how much it's currently holding.

Ignore the three color bars I added...those were my VPD values a week or so ago (not good, killed a sprout)

You want to try to stay as green as possible. Don't freak out when you google VPD, it's a lot of nerdy shit but once you can sort of visualize what's going on in a plant when the VPD goes up or down, you'll start to understand the whole realm of growing better.

That’s awesome. Thank you. I’ve been running a dehumidifier to keep it at about 50% humidity. 49-51%most of the time. I’ll definitely check that out too

 

[Charmanderrr]

My grow is in the closet of a spare bedroom. I run a window A/C and decent size dehumidifier in the bedroom and an inline fan in the closet venting into the unfinished attic plus a good tower fan to circulate air. I'm currently running a 220W LED at 92% and my grow room temp is roughly 7F higher than room temp during lights on.

Concerning VPD here's what I use. I don't really chase VPD but use it to ensure I'm not wildly outside the optimal range. For this formula you need to be able to get an accurate leaf surface temperature. My current VPD runs between 1.2 & 1.3.

HOW TO CALCULATE YOUR OWN VPD:

If you don't like math your in luck here is a formula you can put into a spreadsheet to do it for you. I use excel personally and check the value against a chart like in the above post.

Enter the formula on the next line into spreadsheet cell A10 (copy and paste it).

=3.386*(EXP(17.863-9621/(A7+460))-((A6/100)*EXP(17.863-9621/(A5+460))))

You will type-in 3 values into 3 other cells:

• Cell A5: The air temperature (A5 in the formula)
• Cell A6: The air %RH (A6 in the formula)
• Cell A7: The leaf temperature (A7 in the formula)

Cell A10 will then give you the total VPD for that grow room condition.

Perfect. I’ll download microSoft excel and do this right. I just need a go fund me to pay for the ridiculous prices for those programs these days.

 

[Charmanderrr]

This is a long shot, but I got lucky on my first closet grow. By cutting a hole in the wall I could draw cold air from a cooler location (a basement) and force cooler air in through the walls. If you don’t have a source in your location of cooler air, it’s water bottles and A/C units unfortunately. I do everything I can to avoid adding, since adding adds moving parts. For instance, A/C will change humidity in the room, now you need a dehumidifier, etc. but sometimes that’s the only option. I would just say make sure the source of the air is as cold as you can make it. Sometimes a well-placed fan is all that’s needed….good luck!

I would definitely vent it into the attic or wall if I could but im in an apartment. I have a carbon filter that just sits on the ground face up.

 

[Skunksta]

Inline fan take the hot air out is a must.Also i have found dehumidifier tend to pump out heat themself in a hot room and only help with r/h.Summer growing is a battle and only way to win and sit back is a AC unit.

PS. vent to another room as long as the temps out side the tent are lower an intake would help to from a room
thats not getting the hot air vented to.

 

[copperrein]

Check out LibreOffice as a free alternative to microsoft's crap. Its spreadsheet program is good.

 

[Just A Simple Guy]

Check out LibreOffice as a free alternative to microsoft's crap. Its spreadsheet program is good.

I actually do run LibreOffice as I ditched Windows and run Linux. That was a Copy & Paste I found elsewhere. Any spreadsheet will do. Open Office is another option.

 

[copperrein]

I actually do run LibreOffice as I ditched Windows and run Linux. That was a Copy & Paste I found elsewhere. Any spreadsheet will do. Open Office is another option.

Which distro?

 

[Just A Simple Guy]

Which distro?

Kubuntu with KDE Plasma. I'm running 18.04 LTS and I really need to upgrade to 20.04 LTS.