Need help, leaves turning yellow with brown spots

Hey folks that’s my first grow and I am at week 5, feeding my both plants the same way but for some reason one of my plant leaves turning yellow and the other look great ,
I made research and I think that I have calcium and magnesium problem, so I order Cal-Mag and will possibly feed the plant this Friday with it but I want your opinion as well. I start feeding my plants at week 4 with fox farm, I test my soil and it’s in 6.5 Ph range but the nitrogen was very low so I gave the plant extra grow big and i add 2 tsp. Epsom salt to give more magnesium


I always say to check the ph of the soil by doing a soil slurry test before you chase deficiencies… it does look like Cal/Mag but check ph first


And welcome to the community!!

Thank you , I checked the ph it’s in 6.5 range , I checked the nitrogen and it was very low

Nitrogen deficiency will start at the bottom and work it’s way up. You checked the soil ph and not runoff?

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Not very sure what runoff is but I guess is related with ppm, I don’t have unfortunately ppm meter , I just order ph meter, still learning while I am growing, I know as a first grow i can’t expect much but hopefully i will learn


Do you think i should just feed it Friday with cal-mag or I need to do ppm test before that?

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What’s your watering schedule? Leaves look like it might be over watered. Be sure to let it dry out most the way before you rewater. You’ll need to get a ppm meter so you can tell how much nutes your plant is eating and how much you need to feed. This will change throughout the grow. You’re doing great with the p.h. Keep that up. Adding some calmag might help, but won’t hurt, so go for it.

It’s a 5 gallon pot i water 1.2 gallon water per watering and usually rewater in the next 3,4 days or when I touch the top of the soil and feel it completely dry. Good
Idea about the ppm I will go ahead and get it. Thanks for the tip hopefully my baby will make it , don’t want it to die for sure.

There’s some very good topics on this forum about ppm and feeding. You would be wise to read a few of them. Also you’ll make some mistakes and you’ll learn. Post some pics and updates when you get them.

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:point_up_2: how did you check this seperate from the other nutrients? :love_you_gesture:

I’m a numbers guy and always go to my run PH and PPMs. @Caligurl stated this and chasing deficiencies :love_you_gesture:

It wouldn’t hurt to give cal/mag… I always add a tiny amount of Epsom salts to help as well. It would be really hard to overdo cal/mag. I use General Organics… I think it have molasses in it… at least it smells like it does.

I stick my finger in the soil down to my second knuckle and when it feels dry that far down, it’s time to water.

Also runoff… I water until it runs out the bottom but I keep containers under them. You take the water that overflowed into the container and measure ph and ppm. It’s important to water until runoff if you are using nutrients like Fox Farms and others because you will have a much higher chance of salt buildup and then you need to flush a few times. If you water until 15-20% runoff, you reduce the need for flushing.

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, I got one of those soil testing kits from lows but I will definitely need ppm meter, it’s just shocked me that both plants are the same strain and I fed them and water them the same way and one plant doing great and the other have some issues. Thank you so much for your help


Coolio. Yeah, same strains can act totally different… like my sister and I LOL. Feel,free to tag me any time



I ran ph runoff test and the plant was with ph 4.0 , I immediately flush it and bring the ph to 5.9, feed it with grow big and cal-mag hopefully that will take care of the issue. Seems like the lowes soil testing kit is a garbage, I did the ph test with a pen and it was way off

How are they looking now? Any better?

I switched the light and it start flowering, I thought it was auto, because I bought auto but it turns that it’s feminized I think. I worry that the flower don’t have any pruning done and look like monster, for now it’s ok and hope it won’t overgrow the space. Thanks for asking