Here is what that rust looks like on the youngest. I flushed the plant and took a generic PH reading of the run off while i wait for my hanna ph meter to arrive. My guess is a PH of 5.5 - 6.0 lol i cant tell but it looks to be the same color as the 6.0 ph here is a pic of the test. Anyone have any thoughts on what might be the problem? None of my other plants are having this problem. See my grow journal for more info on my setup. From the other pics i have seen it looks just like a Boron deficiency.
Note: I was also foliage feeding for 3 days with a 1/2 tsp per gallon GrowBig to see what would happen would the water sitting on this particular part for an extended amount of time have burned the foliage. No other plants or leaves have this problem.
Good job on the testing. Are you feeding these plants Ferts? If so, did you take a PH reading of the fert solution before adding it to the soil? Runoff testing is OK but you need to be careful because it can be deceiving. It's like making Coffee, the grounds are left behind in the strainer, but the runoff is clear. Soil tends to collect fert nutrients and trap them, while the runoff may look OK. It's a bit early to tell but the leaves on your plants are displaying signs of a Calcium deficiency. Got any Epsom Salts or Cal-Mag that you can add to your watering? It might help.
I was foliage feeding for 3 days with a 1/2 tsp per gallon GrowBig to see what would happen. Ill test the soil directly and see what the PH is then. And yes i always keep a bag of epson salt around ill try that. Thanks for the reply.
Ok the PH looks to be 6.5 and i used 2tsp of epson salt per gallon of water. I then watered my plants and mist all the leaves. See if that helps.
My new hanna meter finally arrived and i took a proper PH reading. Test 1: Equal parts of water and soil left standing for 5 min. PH = 6.2 Test 2: Watered and tested runoff. PH = 6.1 Test 3: Tap water. PH = 7.8 Using a 30x microscope the rust spots are Dark brown on the edges and light golden brown in the center. The rust spot never progressed. Plant started to look yellowish compared to others so i mixed 2 tbs per gallon of water of grow big and misted plant. After about 1 1/2 hours i noticed nut burn. After viewing and comparing the nut burn sections with the rust spot under a 30x microscope i found both nut burn sections and the rust spot looked exactly alike. I am wondering if a week solution say 1/2 tsp of grow big per gallon of water were mixed and a couple of drops were applied to a leaf section that didn't get much light "Keep the solution from evaporating to quickly" would reproduce the same type of rust like spot.
Just out of curiosity would you mind trying a Test #4? 1 Gallon of tap water and add your ferts, then take a PH reading of the fert solution but don't add it to the plant or the soil. If I'm reading your post correctly it looks like you are adding 2 Tablespoons of Grow Big to a gallon of water, is that correct? If so, you should only be adding a maximum of 2 - 3 Teaspoons of Grow Big to a gallon of water. Here is the FoxFarm feeding schedules for Soil or Hydroponics http://www.foxfarmfertilizer.com/feedingfox.html If I am reading your post correctly, nute burn is definitely a possibility in this situation
Dam i fucked up i used Grow Big instead of Big Bloom. Thank god i was only foliage feeding and not actually watering them. My smallest plant was the only one with the nute burn the rest are all in good shape. The smallest only has min nute burn not much at all. I need to stop smoking when i am taking care of them. The one in the top left corner is the one that was nute burned a little. Note: My 600 Watt MH makes them look yellow but there actually a dark green. I will still do that Test #4 if you want just let me know. Thanks schmedrickk i now know what the problem has been with plant. Nute Burn!!!
Test 4: Tested the 1 Gallon jug i made up with the 2 tbs of Grow Big. PH = 5.1 Whoops lol i feel sooo stupid right now.
Don't feel too bad, it was an honest mistake. In fact I have almost done the same thing a couple of times, but caught myself at the last minute and thought, what the heck am I doing? lol It's kind of strange but I've noticed for some reason myself as well as a lot of other people don't seem to test the PH in the fert solution before adding it to the soil. We always seem to PH test after feeding the plants, and we wonder what the heck is going wrong. I'm glad you ran your test #4, and you can probably see where I was heading with that in terms of low PH and a possible Calcium/Magnesium lockout. I learned the hard way that the combination of rich soil, and adding FoxFarm ferts, will just hammer the PH level. One time mine was 3.8, lol. I guess it's all part of the learning experience though. I'm glad to hear you have the situation under control now and it should be smooth sailing from here. By the way, your plants are gorgeous, you should get some very nice buds off them Since you are using MH/HPS lights, I did have a question to ask if you don't mind? I am thinking about getting a 400W Sunleaves Pulsar Mini Switchable MH/HPS light. My question is, since this light does not have ducting to cool the light, would the fans in my grow tent be enough to keep the tent cool? My tent is 4 x 4 x 7, and I have a 90CFM intake, and 185CFM exhaust. I would like to run the fans for 3 minutes every 2 hours while the lights are on. My fans can turn over the air in the tent every 1 - 2 minutes. So I'm thinking that 3 minutes every 2 hours should be suffcient to keep the tent cool. Thanks!
As long as you have a fan hitting the tops of your plants you should be fine. Me personally with that setup i would place the 185CFM exhaust as high as possible exhausting out of the top or top side exhaust port and have it running when the lights are on. That way when the exhaust fan has evacuated the room the outside air will start to come in threw the bottom intake flaps and the cool air will flow up threw your plants from the bottom up cooling your light in the process and since heat rises the exhaust fan will remove the hot air first. I would then have a clip fan blowing in between the tops of the plants and the light. I wouldn't even use the 90CFM intake. When i bought my tent i bought two 6IN Centrifugal Inline Fan 424 CFM 1. for intake and 1 for exhaust only to learn that i didn't even need the second fan.
Excellent, that is just what I needed to know. My intake is rigged so that the air does come into the bottom of the tent, and my exhaust is rigged at the top of the tent with a Carbon Scrubber, so this should be fine. I have a couple of computer fans that have been Jerry rigged so that they can be plugged into a standard electrical outlet, all I need to do is figure out how to hang them so they lightly blow air across the top of the plants. All righty then, thanks so much for your help, and good luck on your grow. Maybe I'll see you around the boards later.
