Will 28-35% humidity kill my crop?

R

rud3dog

New Member
I used to have a 40% humidity in my tent but it got cold in my area and the house where the tent is at is 30%. I already have large water dishs under the light hoping it will increse the humidity but its not enough. I got a 4x4x6 tent veging on a 600 watt MH. Plants are young but look ok. here is some picks. Btw im using a white widow strain and temps are 74-78f

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Going by my plant, it won't. It's so arid where I grow it doesn't even register on the hygrometer. It still looks healthy enough.

Something I've done to great effect is hanging a soaked towel in the grow area (fluffy one is best), but it'll dry quickly so it's not very practical. It raised relative humidity in my grow area to around 40% from not registering at all, though.

Good luck.

Mao.
 
Well im guessing if I buy a humidifier I would place it in the room instead of the tent. I could use a timer but I dont think a coventional timer would do the trick. so maybe if I raise the humidity in the room the tent will adjust, what you think?
 
it will be fine, during winter months my humidity is anywhere from 20-40% and it doesn't affect my crops at all. I mist them in veg once a day to make sure they get some moisture, but when it's warm I don't even need to do that. You should only worry about humidity ruining your crop if you have too much of it, too late into the cycle, and have bud rot.
 
TheCrimsonK20 speaks the truth. Humidity really only causes problems on the high end. Besides that it'll only affect the rate of transpiration and, thus, frequency of watering. In order for CO2 to enter through the stomata it has to be first mixed with water at the plant surface and turned to carbonic acid. If the humidity around the plant is too low to complete this process the plant pulls additional water from the root system.

Conclusion: low humidity = water a bit more frequently to make up for increased transpiration.
 
You guys rock! So nay to the humidifier? Im currently @ 75f 35% humidity. So is it a bad idea to mist the plants with a sprayer every day or will that cause the leaves to burn? Sounds stupid but someone told me that I should not get the leaves wet at all.
 
:goodluck:i have the same issue. very dry air.
its good to know how often the soil gets dry. check it every other day to be safe. until you get an idea of how often watering is needed
mine drys out every 2 to 4 days. i folair every day w/ distilled. seltzer works awesome.
i also use a wetting agent called coco-wet, with spray n grow. whatever you do keep it moist. opposite of summer time. cold and dry. but they'll do just fine.
additional nutes w/ watering may be needed also due to evaporation.
 
rud3dog said:
You guys rock! So nay to the humidifier? Im currently @ 75f 35% humidity. So is it a bad idea to mist the plants with a sprayer every day or will that cause the leaves to burn? Sounds stupid but someone told me that I should not get the leaves wet at all.
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this is partly true, it all depends on the environment. I mist my plants in veg all the time, but never in bloom. The only way your leaves will burn is if the light is too close to the plants. My t5 never burns my plants, even when the leaves are practically touching the bulb, but i did get a little nervous when spraying under the 600W MH, so I would just say use caution, but it's nothing to be too afraid of. I recently burned a couple of my fan leaves cause the flowering plants stretched more than expected. Didn't affect growth at all.
 
TheCrimsonK20 said:
this is partly true, it all depends on the environment. I mist my plants in veg all the time, but never in bloom. The only way your leaves will burn is if the light is too close to the plants. My t5 never burns my plants, even when the leaves are practically touching the bulb, but i did get a little nervous when spraying under the 600W MH, so I would just say use caution, but it's nothing to be too afraid of. I recently burned a couple of my fan leaves cause the flowering plants stretched more than expected. Didn't affect growth at all.
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Temps dropped into the 20's F room temp is 71F tent temp is 73F 35% humidity. I have some heat issues atm so please understand why I dropped the fixture 10 inchs closer. And yes its a 600w MH, but the outside temps will only be like this for a couple of days. The light fixture is 30 inchs above these guys just to keep the temp ok. I have a box fan that lets new air in constantly. In a day or so Ill have my temps back to normal but im not sure what is better lower temps or less concentrated light temporary. These plants seem to be doing good so far, its almost like they kicked into overdrive. Does the heat or the amount of concentr4ated light kill the plant? Should I raise the fixture up 6 inchs and run my temps @ 65-70F?

First grow and I just dont wanna mess them up. Im including 3 pics of the distance of light to crop and what they curently look like.
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this is how high I got a 600w Mh over them

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Please let me know if its better to raise the fixture and the temps go down to 68f or so or keep them where they are at now. Im sorry im in a place where the weather is always changing.

Again im a first time NOOb please be kind
 
no keep those babies warm. just run that fan over the tops of the plants.
im doing the same. because it fluctuates due to the cold. especially when it's windy and cold. keep the temps above 70 while the lights are on. better root growth. colder soil slows root growth. i raised mine 4 inches they're 20 inches from the lights but i have 2 400w's. got the fan on low keeping the canopies around 74 to 79. 68 w/lights off. i got a fem master kush seed and an ak48 seed germing both from nirvana. winter is for vegging. ill be veggin till april.
can't wait till spring. smoking a fatty. letting the plants get real sunlight. watching them grow. listening some bob marley.
monitor your soil moisture, watch your temps, check your ph and you'll be just fine. they look healthy. no problems mon.
whats your light schedule? i do 18/6.:goodluck:
 
Ok besides the humidity everything is growing great and it seems like they are growing in overdrive. My biggest bushiest plants stem is growing to the side. Its the healthiest and biggest and the stem is is pretty thick for its size. I moved the plant on the other side of the tent but im wondering if I should just get a tooth pick or somthing and tie it straight. I just dont wanna mess up the biggest plant I got.
 
thats completely up to you. if they are leaning to much you may want to use a skuering skick and string. but if you transplant them into bigger pots you can get them to stand up straigher
but it won't mess the plant up at all. are the stems too long? give it a little more time.
 
Awesome thread ya'll...I was also concerned about too low RH but from what I've read, too high is the danger.

Our favorite plant grows well in many different climates...awesome to read I'm not in any danger with lower RH than some...

:)
 
that light is actually further away from the tops than I would normally run my light. I have an open reflector, and I typically run it 6-8" above the plants as my room gets pretty cold, and the heat from the light keeps the plants warm too. Right now, I have some 3' wonder woman plants and some 14" kushberry plants, so the light is about 2 inches above the tallest wonder woman. Only thing I've ever seen from having the lights too close is I had the top of a bud turn white from light bleaching. It didn't affect the bud at all, it just lost all of its color in that spot.

The plants are looking good man. The one that's growing sideways will straighten itself up. Depending on where the light source is in relation to the plant, the plant will actually grow towards it. I've seen this in my garden with the plants on the outside of the light, they actually lean in towards the light. In addition to that, my floor is a little uneven, so if the pot is sitting crooked for a week or so, the plant will fully adjust to grow towards the light. It's really cool how it works, so I wouldn't bother staking them, they will grow stronger as they get older and will be able to handle themselves.

If you notice too much space between the nodes, definitely bring the light closer. the MH should make the seedlings nodes practically be stacked right on top of eachother. It looks weird at first, but once the plant goes into bloom, it gives more space between nodes, and you're thankful for it being so compact when young. More branches = more budsites
 
Thats some really great advice! One thing, I can only bring the reflector to about 1.5 feet till it will send the temps into 80 or so. Where I live the climate changes alot at this time of the year. Ive seen about 5-10 degree spikes in the tent regulary. Ill keep it at 1.5 feet above the plants and see how hot it gets.
At 1.5 feet above the temps are 80f
 
do you have any fans running in there other than the box fan? I don't have an air cooled reflector, so it can get hot, but if I keep a fan blowing on the reflector, pretty much between the bulb and the plant, it takes away most of the heat and I can keep the light really close to the tops. I have about 3" clearance between the top of my 3ft wonder woman and the HPS bulb. No heat issues at all because of the fan.
 
Well I have the can fan and the box fan on at the same time. Do you have a 600 watt bulb? My 600 will not only heat the tent but the whole 20x15 foot room with the window totally open. I had to raise it up but for now Im getting 80f 35% humidity. Im also thinking of when to transplant them. They are getting very bushy, Ill upload a new pic soon. I am also debating on using a 2.5 gallon bucket or 5 gallon buckets. White widow I belive is mostly indica but correct me if Im wrong.
 
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