So my buddy is growing a few plants and a few issues are arising. This is his first time growing in coco. He is using about 80% coco and 20% perlite. All things were going good and looking awesome. He started with teen clones and is about 2 weeks into his grow. Over the past week his plants have started yellowing slightly and has gotten some brown spotting. Also a little lea curling and some brown tips on some leaves. The older leaves were/are showing the spotting while the younger leaves have the yellowing and eventually get brown spots. He initially thought it was a nutrient deficiency but realized his PH was too high. He initially was using boiled tap water PH'd to 6.8 using 18ml/gal of pure blend prow grow. He used this to expand his coco brick and watered with that for a few days. Everything was looking stellar. The transplants flourished. He then started using distilled water ph'd with calimagic added 4ml/gal and 18ml/gal of pureblend pro grow. He was watering every other day or as needed. He has his plants in 2gal geopots and will finish them in those. He started seeing some yellowing or paling of the color. Almost a lime color. He attributed that to fast vigorous growth. But when the brown spots he appeared he knew something was up. He started researching deficiencies and initially thought it was an iron deficiency. Then thought maybe zinc or potassium. He read some info about coco and PH and realized his PH was too high and started suspecting lockout. He went and bought a REAL PH meter and adjusted his water to 5.8. He flushed his plants with distilled water and 4ml/gal of calimagic and a 9ml/gal of pure blend prow grow. He also began foliar feeding with this mix. The plants may or may not have shown a little improvement he said. It's hard to tell. He came over today and said that he flushed them today with tap water that he let sit out overnight to remove the chlorine and adjusted the PH to 5.8 and added 2ml/gal of calimagic. He said he poured 3 gallons of this in his 4, 2 gallon pots and let them run off. He ph'd the runoff at 5.8-5.9 so all is good there now. He also said that in a couple of his small clone pots he noticed some gnats. He is addressing this issue, but doesn't think that they contributed to this issue. He shared some pictures that he wanted posted for him to see if any of you would be able to help. He is growning in a 4x4 tent kept at around 77F running 24hrs under a 400w and a 250w HPS. With a fan for circulation and vent fan to control temps. Temp fluctuation has been as low as 68f-84f but avgs 77F. The 1st photo is not long after transplant. Which he did on the 8th.The next 5 are from the 15th. The last 4 are from today.
Your PH is off and your overwattering them... He really needs to hit the books IMHO. Sounds like you grow in hydro to me, and you are giving him advice as such... PH needs to be 6.5-7 Dont water until dry at 2" under soil.. READ READ READ READ READ READ
He is growing in coco. Coco is treated as hydro when it comes to PH and nutes. Also, it is very hard to overwater coco. I asked him and he checked to see if they needed water by weight of the geopot and by sticking his finger in. He has grown before, but wanted to try coco from all the great things he has read.
not all coco is the same, depending on brand.. some is not rinsed properly during manufacturing, leaving a lot of Calcium in the coco, which can lock the plant out from up-taking magnesium and can even leech it out of the plants. Your plants differently look like they are suffering from a lack of Mg. try foliar feeding with Epsom salts (1 Tbsp/Gal ) it wont fix the problem but it will get the plants the nutrients they need until you do
Your friend started out phing his source water incorrectly, should have been phed @5.5/5.6 for plants to thrive. Coco is notorious for running the ph high which leads to Fe and Mn deficits as the plants are expressing. I see evidence that Zn has presented itself also. I didn't respond initially because you said he had finally sorted his ph, and if so, all will be well. Till then go here and learn: https://www.google.com/search?q=ph%20manifesto&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-USfficial&client=firefox-a&channel=np&source=hp... download ph manifesto, it has a great section on Coco, and put this in your bookmarks for your friend. http://boards.cannabis.com/attachments/plant-problems/281235d1325194867-brown-spots-some-twisted-leaves-some-tips-curled-down-phchart.jpg. Coco is considered a hydroponic hand-fed growers substrate.
Thanks guys. My buddy stopped over after I told him what you guys said. He did some research and is going to foliar feed with Maxicrop liquid seaweed plus iron. He said he plans to use distilled water with calimagic and the maxigro adjusted to 5.8. He is going to stop using tap water too, so he has complete control of what goes in his nute water.