Hi everyone, first-time grower here and I’d really appreciate some help diagnosing what’s going on with my plants.

[NovaStriker]

Hi everyone, first-time grower here and I’d really appreciate some help diagnosing what’s going on with my plants.


I’m currently growing three photoperiod plants:

• Gorilla Zkittlez
• Jealousy (sativa-dominant)
• Purple Haze

The main problem is with the Purple Haze. Some of the older/lower leaves have developed brown/rust-colored necrotic spots, yellowing, and quite a lot of curling/twisting. The newer growth looks better so far, but I’m worried because the plant seems to have slowed down after transplanting.


The Jealousy is the taller, lighter-green plant. It looks healthier overall, but I noticed green growth/algae/moss starting to appear on the surface of the soil. That made me concerned that the substrate may be staying wet for too long.


The Gorilla Zkittlez is the larger and more developed plant. It generally looks healthier, although some leaves also show slight curling/drooping at times.


Setup

• Spider Farmer 90 × 90 × 180 cm tent
• Spider Farmer SF-G3000, 300 W LED
• Light currently around 45% power
• Distance from the canopy approximately 40 cm
• BioBizz Light-Mix soil
• 4 L fabric pots
• Oscillating fan + exhaust/carbon filter
• Temperature currently around 26.5°C / 80°F
• RH fluctuates around 60–65%
• VPD approximately 1.38 kPa

I don’t have a reliable PPFD reading yet, so I don’t want to guess the exact light intensity. The lamp is simply running at 45% from around 40 cm above the plants.


Watering / transplant history


I transplanted the two smaller plants into the 4 L fabric pots on Saturday.


After transplanting:

• Purple Haze received approximately 500 ml
• Jealousy received roughly 400 ml because I stopped early when I saw a little runoff

The Jealousy has not been watered again since Saturday. The pot is now noticeably lighter and my moisture probe is showing that the substrate is getting close to the dry zone, so I was planning to water it tomorrow.


However, I noticed green algae/moss-like growth on the soil surface today. That is confusing me because the pot itself already feels fairly light, while the surface apparently stayed wet long enough for this green growth to appear.


Today I watered:

• Gorilla Zkittlez: 500 ml
• Purple Haze: 500 ml

Jealousy was not watered today.


Water / nutrients


Today the nutrient solution was around:

• pH: 6.28–6.30
• EC: approximately 1.2–1.3 mS/cm
• This would be roughly 600–650 ppm on a 500-scale meter, although the exact ppm depends on the meter conversion.

For the 500 ml feeds I used approximately:

• 1 ml BioBizz Bio-Grow
• 2 ml BioBizz Root-Juice

For the Purple Haze I additionally added approximately:

• 0.30 ml CalMag

I added the CalMag because I was wondering whether the rust/brown necrotic spots could be related to a calcium or magnesium deficiency, but I’m not sure whether this is an actual deficiency or whether the roots are simply having trouble taking nutrients up.


What I’m worried about


I’m trying to work out whether I’m dealing with:

• overwatering / the root zone staying wet too long after transplant
• uneven moisture distribution in the pot
• transplant shock
• pH-related nutrient lockout
• calcium/magnesium deficiency
• light or heat stress
• wind stress from the oscillating fan
• or a combination of several of these

One thing I noticed is that the plants previously started drooping before watering and then perked up after receiving water. That made me think they may actually have been getting too dry in parts of the root zone rather than simply being overwatered.


At the same time, the algae/moss on the Jealousy soil suggests that at least part of the surface has remained wet for quite a long time.


The fan also makes the plants move quite a lot. The leaves and stems are constantly twitching/moving in the airflow, so I’m wondering whether the airflow may be too strong and contributing to the leaf curling.


Since transplanting, growth also seems to have slowed down somewhat.


What do you think is the most likely cause of the necrosis and curling on the Purple Haze?


And regarding the Jealousy: if the pot is already light and the moisture meter is close to dry, but I had algae/moss growing on the surface, would you water it again or let it dry for longer?


I’d also be interested to hear whether you think my EC is too high for plants of this size, and whether adding CalMag was appropriate or whether I should stop adding nutrients until I know what is actually causing the symptoms.


Thanks — any advice from people who have seen similar symptoms would be appreciated.