Possible Excess Nitrogen?

[MLSDRGPNS]

I have acquired some plants out of the blue and don't have a good background on how they were grown previously. They are in soil, but apparently were not fertilised; I have only watered (added no nutrients). They have been in flower for a few weeks, but are showing minimal progress. I had them under poor light for the first 1.5 weeks, but now have good light.

The plants to me appear rather tall and thin stemmed, as well as overall rather dark green. All plants are showing signs of stress in their leaves, some much worse than others - the worst ones have dry curled lighter colored leaves. The healthier plants still have dark green leaves, but are slowly progressing to having the leaf tips point down (or in some cases up). This affects upper and lower leaves, though the upper leaves more quickly progress to dried discolored (brownish) leaf edges and then to curling

.

I've researched and checked the search function, but I don't have enough experience to know for sure what my problem might be. I've grown other kinds of plants before, and am confident my watering is not the problem. I've checked the roots of a few plants by gently pulling the wad out of the pot; they could use bigger pots but the roots are healthy looking and white.

I've attached pics of some of the worst leaves; this is how they end up looking before drying out even more. The pictures lit by natural light from a window. Am I on the right track as to my problem, or could it be something else? I had planned to flush the soil; will this help?

 

[Enforcer]

Hard to tell from just a few leaves. Can you post pics of the whole plant? What are your temps, humidity, medium and nutrients EC/ppm level?

 

[MLSDRGPNS]

Here are some pics of the entire plants; the LED lighting messes with the true colours of the leaves. I'm not sure how well they'll show here; I can zoom in a see good detail but I don't know about others. The first and third pictures are from the healthier plants which are dark green. They are still starting to get the curled leaf tips and burnt edges though. The second and fourth plants are the ones who've been looking bad from the beginning when I got then about 2 weeks ago; they are lighter green but smaller/sicklier and losing more leaves.

I've since noticed that some of the big fan leaves that start to curl and dry out have purple stems while healthier leaf stems are green. All the plants have been in the same conditions since I got them and they started developing these issues, but I don't know what their soil source or exact conditions were prior (apart from them supposed to not have been fertilized and not grown under very good lighting).

Temps/humidity's for the first 1.5 weeks (under poor lighting) were 21C and about 30% just sitting on a table. Since moving into a tent with decent light temp's been about the same but humidity closer to 50% (still need to get a vent fan). They were grown in an unknown soil and unfortunately I'm not able to read EC yet.

 

[MLSDRGPNS]

Is it possible these issues are coming from a combination of stresses related to the moves and changes in light/water/temp etc? I thought these types of plants are fairly resilient but again I lack experience. Are there any signs here that the plants are going downhill or won't yield much... or is this nothing much to be worried about?

 

[Enforcer]

Is it possible these issues are coming from a combination of stresses related to the moves and changes in light/water/temp etc? I thought these types of plants are fairly resilient but again I lack experience. Are there any signs here that the plants are going downhill or won't yield much... or is this nothing much to be worried about?

No, you should be worried. You’ve got something going on there. The 30% humidity wasn’t helping, but you have fixed that. Without a PPM meter and using unknown soil that may or may not have been fertilized, it’s hard to tell what’s going on in your medium.

Are you ph correcting your water?

With the limited information I have and the look of the plant, I would say you have one of two possibilities.

First, (and most likely) the ph of the medium may be out of range for soil (6.0-7.0). Or there are too much nutes in the medium due to over feeding. Either case will cause a lockout of some available nutrients and may present as deficiencies in the plant.

Second, (and less likely), they weren’t fertilized, have consumed all the nutes in the soil and are now becoming deficient.

Since you can’t check ppm’s. I recommend you flush the medium with at least 2x the volume of the pot with plain, ph corrected if possible, water. Then allow the soil to dry out for a few days. Then resume feeding nutrients at 1/4 strength the manufacturer recommendation.

This will “reset” the medium and allow you to make your corrections to the feed and carry on.

I grow in coco, so hopefully one of our many soil growers will confirm or correct what I’m saying. But if it was me, that’s what I would do.

 

[CBDEMON]

You may have had a photoperiod issue, it looks like your plants are re-veged. I see a lot of strange extra stem and leaf growth

 

[MLSDRGPNS]

I have now done a good flush on half the plants as suggested (ran out of good water); still not able to measure the actual pH/EC, but I've melted snow and brought it up to room temp to get neutral - slightly acidic water which is an improvement over the water I used for a few days. I was using drinking water with a well buffered and slightly alkaline pH as it was the lesser of two evils; my tap water has enough sodium to kill lawn grass. My first water source definitely could have been changing the soil pH. I'll flush the rest of the plants tomorrow, then monitor the results and update with pictures.

CBDEMON; it is possible the photoperiod caused issues; I couldn't keep a constant 12 hour dark cycle for the first week or so until I got set up better. I've read even short exposures to light beyond or outside the 12 hour dark cycle can cause issues but was hoping the plants weren't that sensitive and would get back to flowering if I could get them proper conditions within a few days. That said I haven't seen much new veg growth beyond what the plants came to me with and the buds have finally started showing small signs of advancement despite my bumbling; My few pictures don't show that but I'll post more when things get better.

Thanks for the pointers so far; it's been helpful.

 

[Stoeger]

Looks like a reveg, hopefully they turn back soon.