trichomechaser420
Member
Hey guys, so I'm hoping to create a dialogue over some symptoms that I and a number of other growers are experiencing using a local South African soil brand. So far everyone I've chatted to about the topic has experienced some form of the same problem, however, it's a question no one seems to have a clear answer on and may not be possible, but narrowing it down may be useful. I chatted to the soil creator and discussed the issue with him, and he also wasn't entirely sure since his tests come out good, but his testing environment is limited to very large pots and only under one type of lighting.
Apologies if this is a bit too detailed, but this has been driving me crazy.
The Symptoms and Notes
Feeding and Watering Habits
My Thoughts
I have run this soil in three different environments thus far, but also with a lot of other variables between them each. I had some small pollinated plants in 2.8L pots using the same soil, under a dimmed QB - and they came out looking great. I also have some going under a 315W CMH in a 1.2x1.2 and they are also yellowing far less than the plants in my main tent.
Unfortunately, it's not just the lights that differ between the CMH and the QB though, as I also fed the CMH plants a bit less than the others and watered them a little more frequently due to the smaller pot sizes (5L).
Currently, I am leaning to thinking it could be one of the following:
This is my Chernobyl at day 50, it has been limping along with these yellowing leaves for a while now. As you can see, the lower leaves are still very green while the middle and top leaves have faded without interveinal chlorosis.
Someone else on Instagram using the soil was getting the same issues.
Another friend of mine ran the soil outdoors in a pot (pictured front) and you can see that the plant behind it, at the same age, that was planted in the ground is looking much less yellow - suggesting the fade isn't a case of the plant deciding not to uptake any additional nutrients but perhaps a lack of availability or lockout.
Apologies if this is a bit too detailed, but this has been driving me crazy.
The Symptoms and Notes
- Yellowing of middle and upper leaves from around week 3 of flower.
- Necrotic patches on the leaves similar to traditional N-deficiency.
- Slight drooping of leaves and general limping of petioles even when watered.
- Symptoms start typically with a general lightening of the leaves to light green, which then progresses over time becoming more yellow and then almost white, or on other leaves yellow followed by necrotic twisted patches.
- Plants from the same mother flowered under different lighting and receiving less feed looking healthier (unfortunately with both variables changed it doesn't narrow it down too much).
- Plants thrive in veg stage, soil seems filled with nitrogen that's readily available. Plants all seem to do great during their stretching period too, only once bud formation starts do they really encounter problems.
- The few of us experiencing the issue have been using different nutrients, some KNF inputs and others bottled nutrients.
| Contents: Substrates: Compost, Vermicompost, Coco peat, Sphagnum peat moss (sustainably harvested) and perlite. Amendments: Alfalfa meal, Aloe meal, Basalt Rock Dust, Bio-Char (preloaded with microbes), Canna-Kashi, Calcitic Lime, Copper Powder, Dolomite Lime, Guano (seabird), Gypsum, Humic Acid, Fulvic Acid, Frass, Kelp Meal, Malted Barley, Manganese Oxide, Montmorillonite Clay, Soft Rock Phosphate & Zeolite. Inoculant: Cannabis Microbial Consortium. |
- Watering is recommended daily or every second day as it's a Peat-based mix, which I did try and stick to. However, there were 1 or 2 days where they were able to dry out more than optimal, coco would be forgiving enough but not sure about peat.
- Watering is done with dechlorinated tap water.
- Watering is done between 6 and 6.7pH, but shouldn't be as important given the soil medium and organic ferments.
- Feeding is done per the soil creator's recommended schedule, once a week. (Attached is the feeding schedule used along with the nutrient line's makeup.
- Watering is done to mild runoff typically, though tried to avoid runoff after the issues progressed.
- Run-off has tested at 6.5pH
- +-28'C with a RH of around 55% to try and keep the VPD best I can without aircon.
- 1.5x1.5 meter tent
- 2x 240W Quantum Boards
- 10L pots with plants being around 25g yielders.
- Lights are around 40cm from plants, but the tallest plants aren't affected any worse.
My Thoughts
I have run this soil in three different environments thus far, but also with a lot of other variables between them each. I had some small pollinated plants in 2.8L pots using the same soil, under a dimmed QB - and they came out looking great. I also have some going under a 315W CMH in a 1.2x1.2 and they are also yellowing far less than the plants in my main tent.
Unfortunately, it's not just the lights that differ between the CMH and the QB though, as I also fed the CMH plants a bit less than the others and watered them a little more frequently due to the smaller pot sizes (5L).
Currently, I am leaning to thinking it could be one of the following:
- The soil needing to be watered more often than growers here are typically used to, given that coco-based has traditionally been the only soil on the cannabis market, and any drying cycles potentially causing some lockout effects.
- A depletion of nitrogen occurs around the middle of flowering (though as can be seen in image 1, the lowers remain green and look rich in nitrogen still, however the leaves closer to the lights or the middle of the plant go light, so I'm not sold on this).
- A lockout of several macronutrients caused by salts or some other issue with the soil base itself causing lockout (though traditionally I expect to see mg and ca deficiencies locked out first).
- The fact that my plants under my 315w look healthy despite a similar schedule and same soil, I have wondered if the Quantum Boards perhaps increase the uptake (so far I've only seen anecdotal evidence of this, but it definitely feels like I get deficiencies much quicker under my QBs) requirements and that the soil then depletes as it progresses through flower. Especially as it feels like a traditional fade almost, but just way too early. The issue with this however is that plants haven't responded to an increase in feed.
This is my Chernobyl at day 50, it has been limping along with these yellowing leaves for a while now. As you can see, the lower leaves are still very green while the middle and top leaves have faded without interveinal chlorosis.
Someone else on Instagram using the soil was getting the same issues.
Another friend of mine ran the soil outdoors in a pot (pictured front) and you can see that the plant behind it, at the same age, that was planted in the ground is looking much less yellow - suggesting the fade isn't a case of the plant deciding not to uptake any additional nutrients but perhaps a lack of availability or lockout.
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... my 2cents on the yellowing. IMO- You locked out Phosphorus (now deficient). The redish/purplish streaks on the stems and shoots; I saw some completely redish in the photos. Leaf colors.. Looking at your soil amendments, im gonna think you locked it out bc an excess of calcium, zinc. copper and iron. Which caused the middle to upper leaves to take on the redish hue, the tips to burn and curl. Among other micro-nutrients it locked out.
