Need advice: Brownish-yellowing spots on leaves

Hi, i'm pretty new to this, i have been watering with 7.0 ph'd water, and RO has been coming out at 6.5, soil is fox farm ocean forest, plant is roughly 4 weeks old, has been fed once very lightly with dutchmasters formula A and B Grow, but has been showing spots since before we fed it, assumed it could be a calcium deficiency, but i'm not so sure anymore, has been sitting under a sunblaster 125w CFL Flourescent light on a 20 - 4 cycle, temperature has been sitting at a constant 75 - 79, unfortunately other plants have been showing the same problem so would that point more twords a nutrient problem? have been using water from the tap, the brownish-yellowing spots have been drying out and getting very flaky, and seems to be staying more twords the middle and bottom of the edges of the leaves, but has spread to the tips on a few, and the strain of the plant is Blue Cheese, any information i could get before i do something terrible for it would be very appreciated. Thank you.

Soil needs 6.5 ph water, otherwise you lock out nutrients. I would worry less about runoff at this point and focus more on what water enters the medium.

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damn, i been reading 7.0 ph was fine for soil

I don't think that it is a PH issue - I think you might have a calcium/magnesium deficiency by looking at the pics.

Check around and look at other plants online that are cal/mag deficient and decide for yourself and then if you think that may be the case then treat with calmag or switch to a natural nute such as Flora that already is high in calcium and magnesium.

Also - Ocean Forest is a little hot for seedlings and younger plants - I would mix that with happy frog or something like that or transplant in to a soil that is a bit less nute packed

Plant too young, soil too fresh to be a micro-nutrient deficiency problem yet in my opinion.I would lean towards PH and or maybe humidity, as long as you are going very easy on the nutes, with that soil type. Do you have good air movement around your plants? Plant looks very good otherwise. Good luck

Do you foliar feed or accidentally slosh water on the leaves while feeding? I only ask because my plants are very low to the soil and the two bottom leaves did this very same thing from being wet and turning on the lights.

alright i got a better PH pen tap water is reading 7.9 now....


got some PH down, i dont need to flush it right just do normal watering with the right PH?

i watered the plants yesterday should i wait to put in the right PH water?

I had a very similar looking problem on my plants recently. I diagnosed as cal/mag def but it could have been caused by ph lockout. My runoff was coming out too high. To fix it I lowered the ph of the water going in and added molasses to the water. I've found molasses is a safe way to help with cal/mag problems. I use unsulphered 'bootstrap' molasses, I put a teaspoonful in 6 liters of water.
Hope that helps.
MB