Autoflower help please!

[RoseGrow]

Hello, this is my second run of autoflowers and I am having the same issues again. These are 7 weeks old with 8 and 9 week finish dates. I am not sure if these got too much CALMAG or not enough! Top fan leaves are all spotted and light green color, where the lower leaves are green. (I took alot of the damaged leaves off). I saw spots initially and it looked like a calcium deficiency, so I fed 2 ml/gallon calmag per gallon/plant. It seemed to have gotten worse after the calmag. This is an LED grow and tap water at 123ppm. I thought I needed to add some calmag because of the LED even though I am using tap.

I only fed 1/2 strength nutes and mostly 1/4 throughout alternating with plain ph water. I am totally stumped as to what I am doing wrong. I thought maybe it was the light being too close, but I moved it up and still not helping.

My photo period plants seem to do much better for me! Does anyone have any insight as to what may be wrong? I have two Girl Scout Cookies and three OG Kush. Posted some pics below

 

[automan2]

Just a thought as I've seen similar ....Read up on phosphorus...yours may be deficient.

 

[RoseGrow]

Thank you. I think I read in the past that too much calcium lock out phosphorus. I will look that up again!

 

[RoseGrow]

This is such an issue! Excess and deficiency look almost the same! argh. The GSC plants started showing spots, so I fed calmag to all of them thinking they would develop the same issues. I think I shouldn't have done that. They became worse after. The others grew lighter tops and developed the spots too. I don't know why the GSC showed spots though to begin with.

 

[Mañ'O'Green]

@RoseGrow Welcome to AFNMany new growers overdue Cal-Mag and do it all wrong.

Plants must be presented BALANCED nutrients at all times. Some of the individual elements have a broad broad range while others can be a bit narrow. If you feed your plant Cal-mag only that is the definition of out of balance. You are replacing what is in the root zone with a single element. This will cause lock-outs. You need to learn about Liebig's Law of the Minimum. This chart demonstrates Nutrient induced lockouts:

This chart is not in EC it is in weight PPM/liter. It is designed to give you the balance range for the elements in relation to each other. In order for a fertilizer to be in balance ALL of the elements must be present in the ranges displayed. It can be a really big range for many of them. Lets just look at the top 3 for example NPK 100,30,100 - 250,50,300 - 180,40,200 are all combinations that are in balance 50,50,300 is out of balance and can cause lock-outs.

You have a bit of damage now and that will not go away. I would recommend a 50% nutrient flush PH 6.2. Using Balanced nutrients at 50% strength with 5 parts Humic Acid to 2 parts Kelp and B-vitamins (no extra Cal-mag), fertigate until 50% of the volume of your pot runs-off. Then regular water PH6.2 the next 2 times needed to 15% run-off then fertigate normal for the stage of maturity the plant is in.

A foliar application of 5 parts Fulvic Acid to 2 parts Kelp and a pinch of B-vitamins can be helpful but you do not want to spray the buds.

 

[RoseGrow]

I do use other nutrients, Medi-One and I follow the feeding chart at 1/4 to 1/2 strength since others mentioned not to go full strength on autos. I was told to feed CALMAG at the water only watering, but hadn't been giving it. Are you saying I should have been feeding full nutes the entire time? Calmag the entire time? I am not looking to switch nutrients since I have already spent the money on what I have. I use the 1-part plus 4 additives recommended on the feed chart.