Hi all! I was hoping I could get some assistance identifying what this problem island the best way to rectify it. As you'll see below, the middle leaves on 3 of my plants started showing browning at their tips which has progressed towards the stems. The stems on these leaves have also take on a purple hue. Growth has come to a standstill. I think it's a phosphorus issue, but wanted a second opinion. Specifics: Afghan Kush clones about 3 weeks into veg. They're in WaterFarms (DWC) pH'd to 5.5-5.8. I readjust the pH twice a day as it wants to creep up to around 6.2. I'm following the Lucas Method for my nutes (5ml GH FloraMicro and 10ml GH FloraBloom per gallon). PPM is around 550. Water temps are about 75. Air temps range in the mid-70s during the day (72-78) and upper 60s at night (65-68). RH Is around 60% but sometimes gets up to 72%. I'm using a 135w Agromax LED with two 4 foot T12 ballasts for additional supplemental light. The two pics above are from inside the tent and are being fed according to the Lucas Method This one is an organic experiment. It's being given a tea brewed by my local grow shop. PPM is about 730. PH, temps etc are the same as mentioned above. This plant is being lit by a T5 ballast. This last one is actually bag seed that just doesn't want to die. It's literally been through hell. I've attached it because it's showing similar issues. It's being grown in Roots Organic Greenfields soil and is watered with plain RO water as needed. Any assistance I can get with this problem would be greatly appreciated!
[quote name='"tsunamichamp"']Are you giving nutes yet?[/quote] Ok forget I said that.. Lol 730 on you ppm is high. I would cut back. I would have it under 250
[quote name='"tsunamichamp"']Have you tried cal mag? How do the roots look?[/quote] I haven't added any additional calmag. It's my understanding, based on what I've read about the Lucas Method, is that there's enough cal mag in the Flora Micro. I was looking at pictures of deficiencies last night and I don't think it's either calcium nor magnesium - I don't see any rust spots that are indicative of cal issues and what I've seen of magnesium problems don't quit fit either. Each bucket has one long, white, healthy looking root reaching the res solution with other roots just staring to poke out of the hydroton. I expected to see more roots at this point based off of the growth I saw in my aero-cloner, but what I can see appears healthy. I'm due for a res change either today or tomorrow. I'll cut the tea PPM Back at that point. Does anyone have any thoughts on adding additional calmag?
I think I know those pictures or site your talking about. I was taking a look at that awhile back. I kinda thought a lot of those problems and looks blended in with one another. but when I run into such drastic coloration my first response is to see if I'm over nuteing. If not then I add a little of what it might be. Phosphorus is not needed as much until flowering. That's why I don't think it's that. Do you have a product like hygrozyme by any chance?
For young plants, just transplanted into the hydro setup, give them 50% strength nutrient mix to prevent overfeeding them while their young. Gradually bring up the mix to full strength as they grow over the next few weeks or so. Was checking up on the Lucas formula. They still might be a bit young. So lowering that ppm just might work...
I can't believe they want your ppm up to 1300 or so in veg. It just seems a bit sketchy because some strains such as sativas won't usually handle that.
That is nitrogen deficiency and phosphorus def. Yellow leaves are from N and purple stems are P. Up those ppms. Also, I ran lucas formula in dwc exclusively for a year and always had to add cal-mag. The best tip I can give you is always do what's best in your situation, if it worked for someone else is never means it will work for you. My modified lucas formula was 8MLmicro 20MLbloom and it worked great for me but that's just me and the OG I was running. You gotta find what works for you and your strain. Up those ppms ASAP!
Thanks for the advice. Out of curiosity, if they're hungry, and my PPMs have stayed about the same (~550) since the last res change (Nine days ago), is it safe to assume that the plant is/was locked out rather than there not being enough nutrient in the solution?
Thats a safe bet. Did you mix the micro before the bloom? You have to stir the micro in well before adding bloom or you get nute lockout. Try a fresh res change and ph to 5.8
I do mix the micro first, but I'll make sure I mix the hell out of it tomorrow when I do the change. The pH does want to climb back up to around 6.2. Should I be adjusting that more than twice a day to keep it at 5.8 as much as possible? I'm thinking I'll ramp up the nutes to about 800ppm (which is where the mother was at when the clones were cut) and if they burn I'll do another res change and drop it back down.
If you really want to stay on top of it you can adjust ph as much as you like but youll find every res change within the first few days there will be a ph fluctuation. As long as you keep it under 6.1 you will be ok. I cant remember where it is, but there is a ph chart on this site somewhere that shows which nutrients are best uptaken at which ph and it shows that at higher ph's (6.2+) stuff like phosphorus is completely locked out. Thats the importance of ph. 5.8 is optimal but anything 5.7-6.1 is fine. Your girls will tell you what they want. If they look hungry, feed em!