Leaves getting brown spots, tunring dark grey/yellow help (pic)

[marcoochie10]

I have a 21 day old indica (not sure of species) seedling that has over the last few days have leaves start to turn dark grey and yellow. Its currently on a 20/4 hour light cycle, it's fertilizer is 8-12-8 that was bought already premixed with the soil and none has been added yet, it's watered only after the top half of the soil has dried up, its growing under a 150 watt HPS bulb in which the buld is probably 1.5 feet away from the tops of the plant, temps are usually a constant 27C or 80F. My concern is why is this plant doing this? I don't know the PH of the soil, but will be picking up a ph tester tomorrow.

Any help would be greatly appreciated.

 

[Hogdady]

I don't know the PH of the soil, but will be picking up a ph tester tomorrow.

If you had any idea how many plant problems are associated with ph levels, you would know that a good ph meter is essential. And don't waste your money on one of those spa tester kits with the drops and colors b/s. Your ph meter will be your most valuable tool in growing cannabis successfully, so don't skimp on this.

 

[marcoochie10]

Ok thank you. I did a repotting and noticed the roots were completely filled in every nook and cranny. The whole clump was white with roots. Do u think it could be root bound? It's in a pot 3 times as big now.

 

[Hogdady]

Ok thank you. I did a repotting and noticed the roots were completely filled in every nook and cranny. The whole clump was white with roots. Do u think it could be root bound? It's in a pot 3 times as big now.

Sounds like a good call. Please consider my advice on the ph meter...

Another very valuable piece of advice, your soil needs to be amended with dolomite lime. This will help to maintain ph stability thru your grow. Look into it and you will see how important it is.

Good luck!

 

[marcoochie10]

I completely agree. I do in fact have lime mixed in my soil. I have my doubts that my PH is off, but I will know for certain when I pick up the PH meter tomorrow. I'm pretty sure in my limited experience that this plant may just be root bound that replanting it as I have will cure it. Next few days will tell.

 

[Hogdady]

But you don't know the ph of your water. And I think that if they looked rootbound, they most likely were. And kudos on the lime...

 

[marcoochie10]

UPDATE*****

Turns out the plant naturally sheds these leaves, at least that's what I'm guessing from just watching and observing the changes. New growth underneath the dying leaves needed the space so I'm assuming it's natural to the plant. I ended up trimming these low branches off to allow the new growth to get light and grow larger. My plant is very healthy and grown quite large. After 3 weeks I put it into flowering. At that time the plant was 10 inches tall. Now, 1.5 weeks into flowering it's started to bud and is 18 inches tall and doing very well. The reason for the short veg was I didn't know the sex of the plant, it was grown from seed. Now that I know its female I'm taking clones.

 

[sully508]

im just curious what was the problem. and what did the meter say/ph.
ive been w/out a meter for two weeks and have 2 plants 6 weeks into flowering. 12 weeks of 20/4. ill have a new one tomorrow, or the next day. a digital one made by hanna. i finally spent the money. ive always had one but it broke. and just being w/out one especially at this point with buds on top of buds and sugar leaves everywhere. i need to know the ph. id be heartbroken after growing these girls for 18 weeks. now if something went wrong. i got 3 +weeks left till harvest. what were the brown spots? just old bottom leaves?

 

[Ambitious Intentions]

Looks like PH probs. Try to get your soil to around 6.7.Use lime to stabalise ph,it works well.

 

[sully508]

my ph was down to 5,5 this morning. added 1 table spoon per gallon of distilled. its at 6.2 now, plus i added nutes while applying the lime. i spread some into the soil as well.
i used 3 gallons of distilled, tiger bloom, AN big bud, micro,overdrive, GH floralicious plus. tarantula, pirahna, and bud candy. the ph continues to rise. i gave my plants tap water a couple of weeks ago. my tap is 5.4. that plus nute will drop the ph quickly.
gave my plants a bath in selzer / liquid co2. the plants are looking better than this morning. hopefully tomorrow my ph will be around 6.6..
if its still 6.2. more lime and distilled. at least 6.6 puts me in the good range.
i added lime at the begining of the grow and mix in my soiless mix, before seedlings. this is the 1st time had to add lime to raise the ph after 12 weeks of veg. and week 5 on the budding cycle. soiless mix spagnum peat, moss,perlite and vermeculite.the peat moss has a ph of 5.3. so i always add lime to the peat moss to raise the ph to 6.8 before planting seeds.
i lost my ak 48 due to very low ph. then i checked the rest of my plants and the ph was at 5.5. the ak48 was at 4.3 and is now dead. i tried giving it lime.
but too late.now down to 3 plants. 2 wonder woman, and 1 master kush.
check your ph daily. or at least 3 times a week. for optimal nute/mineral uptake. and to keep plants happy.

 

[Hogdady]

my ph was down to 5,5 this morning. added 1 table spoon per gallon of distilled. its at 6.2 now, plus i added nutes while applying the lime. i spread some into the soil as well.
i used 3 gallons of distilled, tiger bloom, AN big bud, micro,overdrive, GH floralicious plus. tarantula, pirahna, and bud candy. the ph continues to rise. i gave my plants tap water a couple of weeks ago. my tap is 5.4. that plus nute will drop the ph quickly.
gave my plants a bath in selzer / liquid co2. the plants are looking better than this morning. hopefully tomorrow my ph will be around 6.6..
if its still 6.2. more lime and distilled. at least 6.6 puts me in the good range.
i added lime at the begining of the grow and mix in my soiless mix, before seedlings. this is the 1st time had to add lime to raise the ph after 12 weeks of veg. and week 5 on the budding cycle. soiless mix spagnum peat, moss,perlite and vermeculite.the peat moss has a ph of 5.3. so i always add lime to the peat moss to raise the ph to 6.8 before planting seeds.
i lost my ak 48 due to very low ph. then i checked the rest of my plants and the ph was at 5.5. the ak48 was at 4.3 and is now dead. i tried giving it lime.
but too late.now down to 3 plants. 2 wonder woman, and 1 master kush.
check your ph daily. or at least 3 times a week. for optimal nute/mineral uptake. and to keep plants happy.

You keep mentioning ph. How are you checking your soil ph? Hopefully not with one of those moisture meters.....