Help me diagnose this problem? Thanks!

[Psyche]

Well, I am a complete newbie! This is my first grow. I did a lot of research and planted my first three seeds on January 5th. I really need your help!
Please note in the photos that the leaves are blotchy, some are crisp; some have rust spots and some brown edges. Here's the set-up:

• Week 9 since sprouted; Week 4 of flowering
• Strains: Autoflower fem seeds from Seedsman. Northern Lights, Blue Dream Gelato OG.
• Current height after Gelato is 8", and BD 6"; NL 6"
• Mars Hydro TS 1000 in 2.3 x 2.3 x 5.3 ft tent
• Three fabric pots–2 gallon each. Sitting on grates to allow drainage.
• Soil: Plagron RoyalMix
• Light: Currently at 100% intensity, just raised to 20" above pots. ppdf about 600 (using Korona phone app to measure). 18/6 light cycle
• Water and feed: ph to 6.0. Every 3 to 5 days. Used epsom salts and milk ; Gave first feed with Playgron Bloom nutes til run-off on 2/18, 2/23, 2/26, 3/2. Then freaked out because the leaves were getting yellow and blotchy. So I flushed on 3/6. Gave half nutes on 3/11 (5 days ago). Photos are of all three plants today. Sorry, I don't have a PPM meter.
• Temp and rh: 74 F to 80F and 45% to 60% rh.
• Air: Currently have both exhaust fan on top and small circulation fan on bottom on low. Have two vents open except close then when rh gets below 50.

I thought a problem was light burn (on the tallest one, the Gelato) so I raised the lights a few days ago.

I hope it's information overload! I like to record everything.

I knew in February they were stunted. What's going on now with the leaves? What should I do? Should I flush again? I've looked at the photo charts but I don't do well with those. It might be a potassium deficiency?? (If you need, better photos, just ask!)

Thanks!

 

[Mañ'O'Green]

Plagron Royal mix is peat based and maxed out with nutrients. In fact you are supposed to rinse it before using according to Plagron. I am going to submit that you have just way overfed them.

Why did you add Epsom salt and milk? Epsom is pure magnesium sulfate - strong stuff. Anyhow You need to understand what I mean when I say balanced nutrients. Please read this:

Tutorial - A word on Nutrients

The proper use of “salt” based fertilizer to grow Auto Flowering Cannabis. Salts: Natural and man made any chemical compound formed from the reaction of an acid with a base, with all or part of the hydrogen of the acid replaced by a metal or other cation. Learning how to use salt based...

www.autoflower.org

I don't know how well this is going to work? Do a major flush, with the last gallon being 40% strength balanced nutrients, Mykos or other bennies, Kelp, Humic Acid and B-vitamins PH to 6.0 -6.4

The reasons we don't know how well this will work is we just do not know what remains in the pot and the plants don't have a lot of time to finish. Flushing really screws up the microbes.

Ps. I have had worse looking plants with good harvests so don't give up

 

[Psyche]

Thanks for the help. Yep, I flushed the soil before planting. I used the epsom and milk because a grower with experience suggested it. About 1 Tb to a gallon of water. I did flush using 5 litres across all three plants. There was runoff of about 1/2 litre. So are you saying flush with just ph water and then before I get runoff, water with one more gallon 40% of the nuturients? That will be about a teaspon of nutrients.

I appreciate that it's hard to know what's currenlty in the soil. What do the leaves tell you? And particular toxicity? Thanks!