Helppp I need help identifying my problem

Your biggest problem is probably over feeding these plants. Coco is primarily something used in the hydro market and you could do better as far as soil mix goes, but you can fix that with the next round. See how your plants are very very dark green? That is a sign that your plants are nitrogen toxic....over-fed basically. You have to consider when growing in a soil media that there are already nutrients contained in it and most decent soil mixes will easily support your plant for the first many weeks of it's life with no additional nutes at all....water, light and soil. In the same way you don't start a baby out on steak and potatoes, you don't start these young plants out by constantly pouring chemicals into them. Now...leaves do not heal. When you see one that is damaged, you can go ahead and expect that damage to remain until that leaf dies. You always look to the new growth on a plant to determine whether you have any major issues going on. If what you are looking at is occurring on old growth, that represents time that has already passed and there is nothing that can be done about it. If you see weird coloration of the new growth or strange things happening there, then you actually have issues. Whenever a plant goes into a fresh soil mix...like with a replant, you have just resupplied the food it needs and you have to allow them time to use the nutrients in the soil before pouring in more. Your plant needs some plain water until the color gets back to that rich blue/green we associate with a healthy plant. Damaged leaves will die and fall off. Actually, all throughout the plant's life, you will have shedding of leaves along the way as the old growth dies. Nothing out of the ordinary. Get rid of the Coco and buy some Fox Farms Ocean Forest or Roots Organics Original. You can take a plant from sprout to harvest in the soil alone if you understand when and how to repot them. MJ is a very fast cycling plant normally and these prepared soils can easily meet their nutritional needs. Nutes are nothing more than plant food and if your plant isn't hungry, it doesn't need them. Light is the thing you should be concentrating on if you want to grow a nice big plant that yields a good harvest. Each plant you flower needs space to flower and spread so light can penetrate the canopy of the plant and most importantly, it needs high enough wattage to force it to produce of the correct spectrum. How many you can flower off depends on whether you have adequate flower lighting for them. If you don't, you're wasting your time doing that many plants. We run 4, 1000 watt HPS fixtures per room and only flower 2 plants under each. By flowering less plants and giving those the absolute best lighting I can during flower, we get much weightier yields than by simply crowding up a bunch in the room for the sake of flowering more plants. Just back off messing with them and let the soil, light and water do their thing. Normally they don't really need fed until they get root bound...and you can just repot into a larger container with fresh soil and toss them back under the lights. The plant will tell you when it's hungry by washing out in color to a more yellowish green instead of the rich blue green they are when they're happy and healthy. Pretty steep learning curve when first starting out, but the more you grow the better you get at it. We all started off as idiots at one time or another too, so don't feel bad. Just chalk it up to experience. By the time you run a few through their life cycles, it will al make much more sense. LOL Best of luck. TWW

 

I don't know why you keep repeating this completely false statement. For the fifth time - mobile elements like nitrogen, potassium, phosphorous, and magnesium first display deficiencies in older growth and immobile elements like sulfur, iron, and calcium first display deficiencies in newer growth.

Why? Because that's what you use to yield your whopping 10oz. per 1000 watts. That's an impressive .28 grams per watt.

 

You never flush coco with plain water and you never just water with plain water. You have washed all the nutrients out of your coco - it's not like soil - it does not hold nutes - nutes have to be given everytime you water/feed. If you feel you have a pH problem and decide to flush - always do it with 1/4 strength nutes - not plain water. What is the pH of your run off? I have found that a pH of 6.0 works the best because Magnesium and Calcium are best absorbed at 6.0 or higher. If your run off is between 5.5 and 6.5 you are good. I would also suggest that you do the Lucas formula for coco for best results - only the micro and bloom are used without the grow - use a 6/9 micro/bloom strength. If you are using tap water you probably don't need cal/mag, but with r/o you will definitely need it. The problems you initially saw was pH related in my opinion. Check your run off pH and always feed with nutes. I feed daily to 20% run off with 1/4 strength nutes for the first two weeks, up it to 1/2 strength for weeks 3 and 4, and lastly up it to full strength. When I switch to flower at about 5 weeks I feed twice a day. Daily feeding replenishes the nutes and pulls in fresh oxygen to the roots. You're running a 60/40 coco/perlite mix so over watering is not possible. Coco will produce fast explosive growth with great yields in a lot less time than soil.

 

You really should never have to flush unless you've been feeding high levels of nutes or you haven't been feeding to run off - those would be the reasons for salt build up. Coco doesn't have the ability to hold nutes like soil so by flushing with plain water you're messing up the Cation Exchange Capacity - always flush with 1/4 strength nutes if you need to flush. I'm glad you have your problem fixed. Good luck with your grow.

 

Looks to me to be a ph problem