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Leaves yellowing during flowering - Need help


Well-Known Member
What Strain is it? Blue Dream
Is it Indica, Sativa or Hybrid? Hybrid 80% sativa 20% indica
How Many Plants? 1
Is it in Vegetative or Flowering Stage? Flowering Stage
If in Vegetative Stage... How Long?
If in Flowering Stage... How Long? 24 days
Indoor or Outdoor? Indoor
Soil or Hydro? Hydro
If Hydro, Reservoir size? 5 galon
If Hydro, Reservoir Temperature? 77 degrees
If Hydro, what type of Medium? clay pellets
If Hydro, what type of Setup? Deep Water Culture
If Soil... What is in your Mix?
If Soil... What Size Pot?
Size (Wattage) of Light? How Many? 300 watt light
Is it Air Cooled? Yes
Temperature of Room/Cabinet?
RH of Room/Cabinet?
PH of Medium or Reservoir? 5.8
Any Pests? No
How Often are you Watering?
Type and Strength of Fertilizers used? Fox Farm Trio 1336 ppm
Size or Square Footage of Room? 3X3X6 feet

I've been in flowering stage for 24 days, I've noticed the tips of her leaves are yellowing and turning up. It started from the bottom and is moving up. Some of the other lower leaves are fading yellow on the leaves also. I've read through symptoms and it seems there could be multiple causes. This is my first grow and I don't want to mess this up this late in the game. Can someone help me with how to fix this? Any suggestions will be appreciated


New Member
Hi Derek

I've had a look at the photos - don't see anything unusual there at all. It looks like you've a very small amount of nutrient burn (but very small) on the tips of the newish leaves ... maybe back off a tiny bit on the nutrients (by now you should be adding extra P&K/ flowering nutrients). Lower leaves tend to yellow a bit as you're nearing the end of flowering ... but if I'm honest, I don't really see this with your plants.

One thing I do notice however from the quick look, is that I don't think they're looking like they are 24 days into 12/12. Sorry. I can't see any pre-flowers. It might just be the definition ...

I think I might see some pre-flowers in top right photo ... and they do seem to have stretched a bit. But I just can't get a closer look.

I assume you're on 12/12 now. Have you stood in your room when lights are out and checked there isn't any light getting in (or LEDS from your equipment ... you know, red operation lights etc).

Worst case, however is you've just given them a little more veg time ...


Well-Known Member
I have been inside to make sure no light gets in. I've been on 12/12 for 24 days. Are the little flowers with the white hairs not preflowers? I see they're difficult to see on the picture I posted. I didn't start seeing hairs until about 10-12 days ago. I am using an LED light. What were you mean about LEDs and red operation lights?


New Member
I thought I might have got a glimpse of them in photo 2 ... they're not visible in the others. Not to my old eyes anyway ...
Yes, the white, wispy hairs are pre-flowers ...
The point about the red operation lights was not very well worded. It wasn't about your LED - but I have a ton of red, orange, blue etc LEDs on all the equipment, adaptors, timers etc that I've had to tape over in order to make the dark period really dark (No idea why the guys don't make their on/off LEDs green!). But as you're seeing pre-flowers ... not an issue.
Anyhow - good luck with the grow. Plant looks fine ... maybe could do with more light / light a little closer as plant seems to have stretched a bit.
Even if you carry on as you are ... you'll still be able to enjoy the product ...!
What LED are you using?


Well-Known Member
I'm using the GalaxyHydro 300w LED. I've kept it between 18-24" from the tallest branch. I'm pretty sure that was the manufacturer recommended distance. Short term memory is a little lacking lol. I'll check again though. They stretched about a foot to 18" since I went to 12/12. I'm looking to upgrade to 600w and do 2 plants after I harvest this one. Wanted to get my process down first. I don't have anything inside my grow room with lights. I have all the cords running outside and plugged into a smart power strip I got on Amazon. It was about $30. Iron-M Smart Wifi power strip. Let's you set timers and power things on/off from your phone.


Well-Known Member
Hey Derek, I've heard of some sativa strains that can take up to 90 or 120 days in flower before they mature. I checked a coupe of seed sites on Blue hase and turns out that they take 65 - 75 days in flower and don't forget that that's under perfect conditions. I've always found those numbers to be very optimistic.

They're nowhere near ready to harvest but the important thing to remember is let it tell you what stage it's in and how it's feeling, don't rely on what you read but use it as a base.

As far as the yellowing tips go cut back on the nute strength by about 25% - 50%, I can't see the tips very well, but it sounds like it might be nutrient burn.

Here's a link to a good pictiorial, the photo's could use better labeling but it is very complete:
Cannabis Plant and Pest Problem Solver - Pictorial
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