How bad is this low humidity for my plants?

I know that for vegging plants like high humidity but i was wondering really just how bad it is to have a constant 20-21% humidity during veg? i know its good for flowering...the edges of some of the leaves are starting to curl upwards which i believe i read somewhere is transpiring? which means the humidity is to low... i have a 250w hps on them and i dont really want to mist them cause im assuming it will cause hot spots....heres a couple pics... the ones in the orange pot will be going to a larger pot probably tomorrow .. and yes i know i need to cover or paint the bare plywood cause its just absorbing whatever moisture is in the closet....

keep in mind these plants are almost 4 weeks old O.O im assuming the humidity and the shit soil i orignally used is what caused their stunted growth... they are now in a nice mix of fox farm soil... would very low humidity really stunt their growth this much?

nah its cool you should just mist them tho.. i have a bunch of seedling in lower than 20% rh and they are thriving you have to create a micro-climate by putting a tray of water beneath the plants (plants sitting in it obviously) and fill it often to 1/4 in. depth of water. the water will evaporate making moist air for the leaves

it can speed growth because of the constant watering adding a heating pad will help too. oh and just plain water till its time to feed

Ok, first things first, putting a tray of water in the area is a good plan. But, putting the plants IN it, not so good. If you have drain holes and I am assuming you do, if not make some. The medium and the roots will suck it up and you end up over watering and if your soil has time released nutes you will not only drown them but also burn the shit out of them.

When they are that small you can put a LARGE zip lock bag over then to up the humidity just be careful of the light and don't start a fire, and misting is great as long as you have the light off and stop when they develop flowers.

The main issue I see here is the 2 in 1 thing. Always put seedlings in their own homes. Unless you have a HUGE pot. When you attempt to transplant even though visible growth is small, at 4 weeks they should have pretty good root systems. Seperating now is going to be a major issue. And if you do not seperate, depending on how large their next home is, you will have a root bound issue pretty soon. That may be part of the reason they seem slow now. My suggestion is to get at least a 6 gallon or larger pot to put them in and do not attempt too seperate them now.

The best growing tip I can offer is too read, study, plan, and act. Tons of great info and people to help here on RIU. Please click the link in my signature. The thread is several how to videos from master growers for first timers. Best of Luck!!

OOOPS, just realized we went over the 1 pot per customer thing several days ago.

typically you should keep about 60--70% during veg and about 50% during flower, but i am in the same boat right now, my humidity is too low, and the humidifyer runs out way to quick , try to soak a couple towels in water and place them in your grow space, you will be surprised, change often tho

thanks guy so technically speaking the low humidity is not so much of an issue. thank you all for the input i really need to cover the plywood in there cause i know its just absorbing all the moisture in the air

other than that do they look ok? i know they are under the hps but at the moment i do not have another light set up in there i will probably later today after my....DRUG TEST!!! ugh...

With plants that small humidity will be a problem. I'm currently growing 4 different strains in a single hydro system and because they are small (less than 6") the humidity is around 26% I'm not concerned because as the plants grow bigger they release more moisture into the air. I know that after week 3 of flowering (currently still vegging) I'm gonna need to run my dehumidifier as RH quickly climbs up above 50% when I've got 4x3ft plants in there.


Yes growth will be slower with the lower RH but it's not much of a problem. These plants are fairly rebust and adapt to their environment pretty quickly.

yea they seem to be growing more and more everyday i just assumed they would be MUCH larger by now but the hard life ive given them since they sprouted im sure is the cause but hopefully the changes ive made will be good for these girls and they can grow nice and big and give me lots of beautiful flowers

I'm having the same issue, with humidity around 16%, will add humidifier and see what happens.

My plants have had mostly low humidity all there lives and they seem to be doing fine in there 4th week of flower.

alphawolf.hack said:

nah its cool you should just mist them tho.. i have a bunch of seedling in lower than 20% rh and they are thriving you have to create a micro-climate by putting a tray of water beneath the plants (plants sitting in it obviously) and fill it often to 1/4 in. depth of water. the water will evaporate making moist air for the leaves

Click to expand...

You just saved my ass... my humidity is in the high 30's and my plant is in the seedling stage just 8 days old. What is the optimum humidity for seedlings and veg?

doesn't weed grow in dry ass places like Iran and Afghanistan?