Temp goes from 81.5 to 69.0

I am curious if i am doing damage to my plants? when my light is on it

never changes really from 81.5 always stays right around 81.

I am on a 18 on 6 off cylce. I lowered the light to get closer and cut the oil heater off.

My light cycle is 2pm to 8am. Well i just went down there and the temp is at 69 is that ok?

I have read many times to mimic what the weather would be doing outside,

so is that to cold to have them at for about 2 hours, or when the light gets turned off,

should i turn the oil heater back on, to keep it around 80 ALL the time?

ANyone Anyone lol +rep for the advise i need

My understanding is that it is actually preferable to have up to a 15 degree drop when the lights are off. I guess it simulates night better and perhaps gives the plant a chance to rest.

get a fan on 18/6 to cool the HPS lower your lights on temps! 81F is ok though 75 light 65 dark is ideal,I hit 70F and 60F dark..

benandtom said:

My understanding is that it is actually preferable to have up to a 15 degree drop when the lights are off. I guess it simulates night better and perhaps gives the plant a chance to rest.

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What i thought +rep ty

if you are comfortable in it then your plants are comfortable!!

Straight up G said:

get a fan on 18/6 to cool the HPS lower your lights on temps! 81F is ok though 75 light 65 dark is ideal,I hit 70F and 60F dark..

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Thats what im doing, so i think im ok just paranoid lol.

ima keep it around 80 when light is on, and 70-65 when its off,

I am doing this in a cold basement, so i dont need to exhaust the heat from my light, it actually is a life saver.

go primo if you can though right?, save any stunted growth heat stress that can be avoided..?

Moochbuds said:

Thats what im doing, so i think im ok just paranoid lol.

ima keep it around 80 when light is on, and 70-65 when its off,

I am doing this in a cold basement, so i dont need to exhaust the heat from my light, it actually is a life saver.

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yea I use my HPS to hit primo temps too, IMO best way

Straight up G said:

go primo if you can though right?, save any stunted growth heat stress that can be avoided..?

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So your saying primo is 70 lights on and 60 lights off right?

Moochbuds said:

So your saying primo is 70 lights on and 60 lights off right?

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No they are my temps, primo is under 78F [the temp the plant begins to use energy to dissipate heat rather than put it into growth]

so under 78F and 10F lower than that dark.

but 80ish is ok.

Thank you so so much, THIS SITE RULES lol

Moochbuds said:

I am curious if i am doing damage to my plants? when my light is on it

never changes really from 81.5 always stays right around 81.

I am on a 18 on 6 off cylce. I lowered the light to get closer and cut the oil heater off.

My light cycle is 2pm to 8am. Well i just went down there and the temp is at 69 is that ok?

I have read many times to mimic what the weather would be doing outside,

so is that to cold to have them at for about 2 hours, or when the light gets turned off,

should i turn the oil heater back on, to keep it around 80 ALL the time?

Click to expand...

Hi there,

My advice is to never let your temp drop below 70.

Make your thermometer is right next to your plants and not on the wall somewhere!

If your temps get over 80 and stay under 90 while your lights r on they actually like it better and it opens up the roots for all that CO2 intake! Lights off never under 70 but it is good for the plants to actually have that elevated heat and bit of a drop while they sleep..... People are obviously letting it drop below 70 and if you have a hearty strain thatn it shouldn't be too much of a problem as they are more resistant.

Spinelli said:

Hi there,

My advice is to never let your temp drop below 70.

Make your thermometer is right next to your plants and not on the wall somewhere!

If your temps get over 80 and stay under 90 while your lights r on they actually like it better and it opens up the roots for all that CO2 intake! Lights off never under 70 but it is good for the plants to actually have that elevated heat and bit of a drop while they sleep..... People are obviously letting it drop below 70 and if you have a hearty strain thatn it shouldn't be too much of a problem as they are more resistant.

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Agree, my plants seems to love it when it is 80-82. If you look at my journal you will see I have my temps right, and sitting in the right spot.

Very nice and clean set up you have going there! Keep up the great work!

drastic temp changes can shock plant and slow growth. Rule of thumb is no more than a 15 degree swing from max to min. Also avoid high temps (over 85 degrees) My set up runs at around 82 or 83 max and then drops down to low 70's at night. Large temp changes can also cause increased humidity levels and may present a danger to your crop in the form of mold. Also, if your humidity starts to raise to high, it will also impact the ability of your carbon filter (if you use one). Moisture is your active carbon filters enemy....

Hi there,


I agree.......... Well said!

How bout them housewives of Orange County, YIKES! lol!

Ok, well from what you all have said, im golden!! stays 81 with light on, 70 with light off thanks very much

BTW i just added new pics at my journal, should help with the distance ?'s

Moochbuds- Here are some pics of my current 400w grow at week 4 of veg. My temp varies between 75-82 during the day and between 64-70 with the lights off, and my girls do just fine. One note though-I've been told that the strain I'm growing (opium) likes cooler temperatures, so dropping down to the low 60's might not work as well with the strains you're growing.