Brown and curling leaf tips, dark leaves

Hi. I had two plants that I started last year around July and they grew great for how well I've done in the past. They were stolen and I'm now left with three clones that aren't doing so hot.

plant1

plant2

plant3



As you can see from the pictures, the sativas have brown leaf tips and one has massive curling. On the underside of the first one the whole leaf is brown and wilted.

The indica has turned very dark green (was about as light as the sativas, but around 2-3 weeks ago turned dark green). I thought it was a nutrient deficiency, so I gave it nutes, but still no sign of getting better. The indica also has brown spots but not as bad as the sativas.

The plants get minimal light being as they are outdoor plants and it is winter. I bring them in every night so they don't freeze, but there's not much I can do about light.

I'm thinking that the sativas are getting light brown from overwatering. About a week ago I flushed all of them because I have no resources to check pH. While this method worked during the summer and fall, I don't think it's hot enough for the water to evaporate which is my guess as to why this is all happening.

Right now I have them under a single flourescent at my desk, and they are on top of my batery backup where I hope the warmth will help evaporate some of the water.

Also, you can see the soil is weird. Its called vermiculite and it's the only thing I had lying around at the time. It soaks up water like a sponge but (suposedly) gives the plant roots room for air. I'm thinking I ought to transplant them into some normal soil, however I don't think it's a good idea to transplant them when they are this weak.

I would be very greatful if some experienced growers would give me some tips as to what the problem is or if it's as I described.

I'm thinking now that this is a phosphorus deficiency due to a high pH (my original inclination was a phosphorus deficiency but I gave them more nutes which didn't help). I've been reading around some more of other people's posts around the site and the browning tips and curling are definite signs of phosphorus deficiency. Since I am not adjusting the PH of the food and they are in a soilless medium, this sounds about right. I have ordered a digital pH meter and I'll update on what pH water they've been getting when I find out.

Today I added about 1 tsp of vinegar to 16 oz of food to help lower the pH. Although I am unsure what the pH is, I am fairly convinced that it is too high.

Also, I've transplanted the plants into a more aerated medium. I've read that perlite and vermiculite makes a good medium at a 3:1 ratio, so that's what I'm trying.

Here's an update on what they look like... It appears as though the middle one is too hurt to come back, but I have hope for the other two plants.


Phosphorus deficiency due to a high pH... am I on the right track?

Also, my hope for these plants is merely to get them to grow large enough to take fresh clones. I've had them under light all night until I go to sleep now which is probably stressing them out more if they are beginning to revegetate. They are only getting around 14-15 hours of light a day now (8 sunlight and remainder florescent), but it's more than they've been getting. Damn these plants can take a lot. I hope they make it through all this shit.

looks pretty bad man, might have to find more clones. you can get a pH dropper for 7-10$, should be good enough to get your pH in the ball park. you should really invest in that before starting over again. Better luck next time!

you need to change your growing medium. It is impossible to successfully grow with only vermiculite. It has zero nutrient availability for the plants. YOu are lucky they got this far.

Solution = dig up some soil from outside and let it get to room temp (depending on where you live). Then transplants those plants already!!

urgod said:

looks pretty bad man, might have to find more clones. you can get a pH dropper for 7-10$, should be good enough to get your pH in the ball park. you should really invest in that before starting over again. Better luck next time!

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As you sugguested, I have invested in the needed pH equiptment. I bought a meter, calibration liquid, and powder pH down. I'm only using vinegar at the moment because the pH stuff hasn't arrived yet. pH imbalance was my most recent hypothesis; from your response, I'm guessing you agree with it.

ynkessuck247 said:

you need to change your growing medium. It is impossible to successfully grow with only vermiculite. It has zero nutrient availability for the plants. YOu are lucky they got this far.
Solution = dig up some soil from outside and let it get to room temp (depending on where you live). Then transplants those plants already!!

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Surprisingly enough, I grew two plants to about 3-4 feet in pure vermiculite last fall before they were stolen. If you take a look at the second post, I did change the medium, however not into dirt. I read an article describing how to do it. It's essentially a hydroponic grow, but I'm using hydroponic nutrients.

Supposedly if you get hydroponics going right, it allows the roots more oxygen and thus a better root system develops than that which develops in soil. However, as I am a noob to this, I would probably be a lot better off taking your advice and switching to soil.

When I transplanted them, I took a look at the roots. Even though the verm was incredibly moist, the roots were still white and did not smell rotten. This eliminates my hypothesis on root rot which is why I transplanted them out of the vermiculite in the first place.

So it's not root rot, and it's not nutrient deficiency in the feed, as I've been giving them more than enough bloom nutrients (3-12-6). It's definitely a phosphorus deficiency at the leaves, but the soil has enough phosophorus. Everything is pointing to pH imbalance; I think this is the correct diagnosis. I won't know for sure until I get my pH meter, but for now I will act on the hypothesis that the pH is too high.

Thanks for the responses guys, I appreciate it.

Great news! It looks like there's been no more death on the leaves due to phosphorus deficiency. The vinegar must have worked! It's only been a bit over 24 hours, but when comparing the brown spots now to the brown spots yesterday, there's been no progression.

The almost completely dead looking plant lost it's last bit of green, it's gone. But the other two look fantastic. (maybe fantastic is the wrong word, but new growth ;] )

The pH equiptment should be here tomorrow or the next day. I'll still come back to this thread to post the pH that was causing the problem, but this problem's been solved. Any more news about these plants, other than problems, if posted, will be on the log section.

try to grow in perlite, you will need a complete nutrient with all micro and macros lowes and homedepot wont cut it.

keep it real. said:

try to grow in perlite, you will need a complete nutrient with all micro and macros lowes and homedepot wont cut it.

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Are you saying Lowes and Home Depot won't work for obtaining perlite? Home Depot seems perfect for getting perlite.

Or are you talking about obtaining the nutrients from these places? As I already mentioned, I've got hydroponic nutrients...

He's saying that anything from those two places won't have the right macro's and micro's in one bottle.....

I'm using Dyna-gro which seems to be good enough for many growers on this forum.