Utopia Haze on coco under LED

ROOT ROT IN COCO?! First, sorry for the late update: a busy schedule last week kept me from taking care of my plants and updating timely. However, it’s been one of the worst weeks in (almost) a year of growing. I already talked about the droopiness in previous updates, but this week it became much, much worse. I was planning on fertigation again yesterday, but since they were looking so horrific, I decided to postpone. The nitrogen excess was clearly solved, all seemed to be in check. But the droopiness persisted and, as I already mentioned in my previous update, I started to worry it might be a problem with the medium. After I trained and defoliated a few days ago, they became more droopy every day and also growth slowed down. Today I also noticed some leaves with a bunch of brown spots. I decided to open up the pots and as you can see from the pictures: not all roots are looking healthy. A bunch of them, especially near the bottom of the pot, were brown. The other plant (I didn’t take rootzone photo’s of that one) was looking worse. Basically all the root tips poking through the raster at the bottom of the pot were brown. It smelled like wet clothes left in the washing machine with the door closed for 48 hours. WHAT CAUSED IT? I reused my coco from last grow, while there were still old roots in it. I had it dry out for 2,5 months, than rinsed it using a sieve to get rid of the coco dust. Where I completely sanitize the tent and all the equipment with a 300 ppm active chlorine solution (sodium dichloroisocyanurate), I didn’t do anything to get rid of pathogens in the old coco. Before I started this grow, I had the rinsed coco already in the pots for about 2 weeks and I ‘fed’ the coco a CalMag supplement that’s also high in N to buffer it. It was basically wet (and quite warm, as it was still summer temperatures at that time) during that period of time. When I transferred my seedlings into it, the seedlings were way too small for the big pots. Even though I fertigated only twice a week, the coco stayed wet during long periods of times. Another factor was the N excess (see week 4 of this diary): pathogens like N-rich mediums. Also, the pots were standing in plant bowls. I always removed runoff water from the bowls, but off course, the pots keep dripping out for a while and fill the boll a bit long after fertigation. The bottom of the pots inside the AirRap pots are a little bit raised, so I was never worried by it. However, the outer plate wrapped around the bottom of the airRap pots basically form a shield for air to get under the pot. There’s just I tiny split between the bowl and the wrap of the pots. If there’s water there, it will be completely still, no air movement and dark. Moreover, due to the lights and the fact that both the pots and the bowls are black/dark, I suspect temperature within that space can easily reach 25c, if not higher. And last, I used to fertigate with a water temperature around 22c, which is on the high side. Hence, without really realizing it, I created the perfect environment for the fungus to thrive and multiply. Especially directly under the pot in the bowls, were the outer wrap of the pots creates a enclosed spaced were RH is probably above 90% and temperature 25c or higher. Training and topping them in the last weeks weakened them and there you go. The evil pathogens can take hold of the plant. However, this doesn’t seem like a lost case to me. At least 80% of the roots still look healthy, although I don’t know how they look deeper into the coco. TREATMENT 1 In order to give them a fighting chance, I first need to kill as many spores as possible. Hence, I flushed both plants with at least 5 liters of active chlorine mix at 150 ppm per plant. I pH the water down to 6.8 (our tap water is around 8). This way I’ll prevent a pH spike in the medium, but the water isn’t too acid to react with the chlorine transforming into the dangerous chlorine gas. I used my pressure sprayer for it, so I could make sure that the mix was distributed everywhere in the pot. I also sprayed underneath the pot, to get all the roots poking out the raster cleaned. I also sprayed the sides of the pots, a lot of regular used equipment and the bottom of the tent. The plants were completely soaked with the chlorine solution and I let them sit (outside the tent) for about 30 minutes. In the meantime I cleaned the tent and regularly used equipment, first with the chlorine and then with plain water. 2 Now it was time to get the chlorine out of the system. I flushed both plants in the bathroom with 10L of plain, pH’ed water. I also rinsed the sides of the pots and the plant bowls with tapwater. Last, with the pressure sprayer, I rinsed the leaves of the plants with plain pH’ed water, to get rid of any excess chlorine that might have gotten on the leaves. 3 After leaking out for a while, I fertigated with a light feeding mix, but with my regular dose of CalMag (which is already 50% of the recommended dose on the bottle), since I probably flushed some of the buffer away. I also added 1.5 times the recommended dose of CannaZym (which is designed to ‘eat dead roots’ and prevent fungus from taking over). It resulted in an EC of 1.0 and I pH’ed it down to around 6.0. The temperature of the water at all 3 steps was exactly 18 degrees. 4 I placed the plants back in the tent, but I elevated the pots above the bowls with a raster (just look at the pictures). I also placed a fan really low, so it could blow under the pots. I can now feel wind under the pots. I reduced light strength significantly. It’s now just as intense as it usually is during the second week of my grow (small seedlings). If the plants improve, I’ll slowly increase the light. I also putted a oscillating fan directly on the leaves to blow them dry. After an hour or so, the leaves were dry and I slowed the fan a bit to normal setting (nice, gentle breeze for the girls). TIME WILL TELL For now, I’m just really, really curious to see what is going to happen. At the moment, a few hours after the treatment, the plants have perked up a bit, especially Mace: her grow tips are praying and I haven’t seen that the last 5 days or so. It’s probably been refreshing for them. However, to complicate things, I I’m out of town for a week from next Friday. I was actually planning on automating fertigation before my absence, but I can’t do that right now (have to make sure the coco dries a bit before every fertigation to prevent new root rot to occur). I’ll probably have someone hand water them once or twice during my week of absence. I’ll have the coco dry out a few days between every fertigation, until the plants fully recover. If the plants recover at all. For now, all I can do is pray to the Ganjagods to spare my girls. Thanks for stopping by and happy growing!