Rust color spots on older fan leaves

[Newbie grower]

Hi guys. I have a problem with my two week old seedling. It’s a Tangie Matic autoflower seed. My grow medium is as follows 7.5l compost 7.5l coco peat 4l perlite and 2l vermiculite and 1 handful of bone meal. After the 3rd day that she popped out the soil, I noticed that she had brown rust color spots on the leaves. I was using distilled water with a ph level of 6.5 as my tap water in the county I live in is pathetic. When I noticed that I immediately started using nutes but at a very low dosage. It seems to be getting better, it looks like it could be a Calcium and magnesium deficiency but been my first grow I want to hit the nail on the head and fix it right the first time instead of loosing her. Can someone please assist me with this. I’m using a 600w COB led grow light from Morsen. Which pushes around 100w. I’m growing inside my cupboard in my spare room. D

 

[Old Salt]

to the forum!

I tend to agree with your diagnosis of a cal/mag deficiency. The overall condition of the plants looks poor. It could be over watering. I think you need to follow Emilya's guidelines set out in her paper "The Proper Way to Water a Potted Plant."

 

[Remystemple]

to the forum!

I tend to agree with your diagnosis of a cal/mag deficiency. The overall condition of the plants looks poor. It could be over watering. I think you need to follow Emilya's guidelines set out in her paper "The Proper Way to Water a Potted Plant."

but, but, but "you CAN'T over water in coco!!!"

 

[nivek]

compost might be 'hot'

 

[Old Salt]

but, but, but "you CAN'T over water in coco!!!"

It's not coco and an inert substance, so the rules for soil apply instead of those for drain-to-waste.

Yes, you can over water in coco when using a drain to waste system. It's only during the early stages of growth that this applies. That is unless you place the containers in the runoff. Then all bets are off.

 

[Remystemple]

It's not coco and an inert substance, so the rules for soil apply instead of those for drain-to-waste.

Yes, you can over water in coco when using a drain to waste system. It's only during the early stages of growth that this applies. That is unless you place the containers in the runoff. Then all bets are off.

missed the compost part.

 

[Newbie grower]

to the forum!

I tend to agree with your diagnosis of a cal/mag deficiency. The overall condition of the plants looks poor. It could be over watering. I think you need to follow Emilya's guidelines set out in her paper "The Proper Way to Water a Potted Plant."

Hi Old salt. Thanks so much for your info. I will read through Emilya’s paper and do as I should. I don’t water every day. For instance, if I water Monday morning. 300ml I will water Tuesday evening and so on... I don’t get any run off when I water bcz the plant is still so small of course.

 

[Newbie grower]

Hi guys. I was correct with calcium and magnesium deficiency. My plant is now thriving, it’s 30 days old I just done my first defoliation of around 5 big fan leaves that we’re blocking the light for my bud sites... I hope I didn’t stress her out to much will see in the near future how she reacts. The only training I’m doing is LST did not top my plants or anything other form of LST

 

[Old Salt]

Glad you have the problem solved!