Slowish dwc growth Blue Kush.

Hi everyone.

So as the title indicates I'm having a problem of sorts. I feel as if my girl should be much bigger by now.. I'll give some specs on the grow.

Light: 250W HPS with a dual spectrum bulb in a cooltube
Distance: about 18cm/7inch from canopy
Strain: Blue Kush from Dinafem seeds
Medium: DWC, rservoir temps constant 66F, ppms at 740 and pH stable at 5.8
Extraction: cooltube is connected at one end to some ducting and that to a 250cfm fan
Temps: constant 24-27C/75-80F
Humidity: pretty low, I'd say 20-30%
Nutrients:GH 3 part flora series
Age: around 25 days...

You see the problem is I feel as if she should be much bigger, for instance when I compare to other people grows that have more or less the same specs. I mean, she's just starting to develop her fifth node, surely should should be past that at nearly A MONTH of growing.

I was really hoping to break the 100g mark, but it looks like that won't be happening.

I mean I was thinking it could be the humidity, but a lot of people wave their hand and say their girls do fine with low RH.

I really cannot afford to veg for a long period of time, but I would also want some decent quantity.

Thanks for any help, all is welcome.

Sorry for the poor quality.

I would like to top her at least once before I flip to flower, but I'm still unsure whether or not that'll do her any good.

i'm seeing some slight nute burn (curling and twisting leaves), i'd drop the ppm to 500. and increase humidity to 50% minimum. also get a fan blowing overtop plant to bring in a little more co2. also the slightly low temp could be a factor. are you sure the water temp is 66? low temps below 64ish can slow growth. could be the strain. i'm not seeing any major issues. how old is that bulb? poor light and low temps are the main factors that slow growth. i think you need to veg to at least 12" if you want to get much yield.

Thanks mandy for the reply.


I have a little fan blowing between the cooltube and canopy, the light itself is 5 months old.

Hmm... you think the ppms are to high? Ok, I'll change the reservoir today and go easy on the nutrients, probably hald of what I used last time. I'll keep you posted.

It would probably benefit if I could add a humidifier in the grow box, but I have a cooltube and all thst mist going through the bulb is asking for trouble.

Ok, so I lowered the ppms to 480, so that's about 200ppms worth of nutrients. We'll see how it goes from there...

just setting a bowl of water in front of the fan would help. i don't think the increasing humidity would damage the light providing you don't put a fogger right under the light. i use a couple of cheap ebay bought foggers in a 5 gallon bucket. never heard of anyone having electrical issues with high humidity. i see you grow in a wardrobe, don't have any experience with that. could lack of fresh air or poor air exchange be slowing growth? your water quality must be poor if you have over 200ppm's of unknown crap. try to mix in some rain water or buy distilled water. my grow dramatically improved after getting a reverse osmosis unit. my water is about 170ppms

Reduced the ppms to 380.

Well, I mean 200 ppms of tap water is considered clean. but you're right, I should invest in a RO system, that would definitely help...

Damn, after scouring the internet it does seem that I overfed, too much nitrogen. I really hope the lowe ppms will sort it out and my girl resumes growth.

By the way, thanks mandy for your help.

Yea I would say that there are a few things you could fix. I would raise that light up a few more inches to like 10-12". Your low humidity is causing the leaf curl/twisting. My current batch had similar symptoms and I went and snagged a cheap ultrasonic humidifier from your local pharmacy/grocery store and it got a lot better. She does also look a bit fried from the nutes. With higher RH she would probably be able to uptake that much of a feeding no issues. You can also try misting her when lights go off. Find some organic aloe vera juice, mix a bit with some water in a spray bottle, and give her a good spray every few days at night. She should recover well

Mineralz said:

Yea I would say that there are a few things you could fix. I would raise that light up a few more inches to like 10-12". Your low humidity is causing the leaf curl/twisting. My current batch had similar symptoms and I went and snagged a cheap ultrasonic humidifier from your local pharmacy/grocery store and it got a lot better. She does also look a bit fried from the nutes. With higher RH she would probably be able to uptake that much of a feeding no issues. You can also try misting her when lights go off. Find some organic aloe vera juice, mix a bit with some water in a spray bottle, and give her a good spray every few days at night. She should recover well

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Mineralz thank you so much fo the help, I'll definitely do everything you say. I'll get a better hydrometer as well, to make sure I keep that RH in check. Hopefully she'll rcover over the next few days and I'll be able to switch to flower after some time.