Dry Crispy Leaves with White & Rust Spots


I’m new to growing cannabis and excited to start this journey! Need to some help with my girls (2-Sour Diesel and 1-Jack Herer). After germination, the seedlings Jack Herer had a yellow tip right from the start while the Sour Diesel looked fine. A germination dome with heater pad was used within a starter plug soil. I transplanted 1-Jack Herer and 1-Sour Diesel directly into a 5-gal. fabric pot. The soil is top 2/3 soil of Fox Farm Ocean Forest and bottom 1/3 California Super Living Soil. The other 2nd Sour Diesel was slow to germinate, so I kept this girl inside the germination dome a couple days longer. Then, she was transplanted into a 1-gal plastic pot till her leaves extended out to the edge of the pot with Ocean Forest soil. I applied some Mycorrhizal from Dynomyco to the roots prior to transplanting, which I also did to other two (2) previous transplanted girls by mixing into the top soil and watering w/ distilled water. The Jack Herer always seemed to have dry crispy bottom leaves right the start, see below. I figured it was nutrient burn, but not 100% sure.

I’m in a 4’x4’ grow tent in the extra bedroom in the basement. Running a positive pressure environment w/ an intake fan w/ carbon filter taking air from the lung room and an exhaust fan w/ carbon filter exhausting air to the outside through a neighboring bathroom exhaust fan’s ductwork (cap-off in the bathroom). There is a CO2 exhaust bag (between 800-1200ppm) and humidifier in the tent. The Spider Farmer SF2000LED and two (2) Bud Grower lights (120w each) are on 24/7.

Fast forward, my girls have gone through a lot in the first 41 days and need some help.
I’ve been checking run-off PH and seems to always be hoovering around 7.5. Been using distilled water, adding 1 Tsp of unsulphured Molasses every other watering. Two (2) days ago was the 1st time I fertilized with Fox Farm trio (870 ppm & 6.38PH). The run off was 1500 ppm to 2000 ppm which seems very high. Humidity is around 46%-50% RH w/ 75F-78F temp.

Looking for help to figure out what’s my girls leave to have discoloration and dry crispy leaves.

Was having the same problem on my 1st grow. Was also doing a living soil. I purchased a filter to filter out the chlorine & chloramine from my tap water. Started to add some cal mag to the water and adjusted the ph to 6.5. My plant recovered.

You might not need the filter with distilled water, but perhaps the cal mag and 6.5 ph might help…

Had this problem also on my first grow. Cal Mag will fix :slightly_smiling_face:

Ok, I’ll pick some up. Do you recommend a brand or is cal-mag the same across all manufacturers?

There are several brands I guess…I’ve been using Bush Doctor CalMag from Fox Farms with no problems🙂

Perfect! I’ll follow up once I give it a go.

Should I trim off the serve damaged leaves from cal-mg deficiency?

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Just got some City Bloom Cal-Mag and watered the girls yesterday and foliar sprayed with distilled water + Cal-Mag over leaves today.

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Steve my grow bro what is up? Ok so Just popping in to give some advice take it or leave it. I am now organically growing but I used fox farm for the basically my first 2 years of growing. If you are using any Fox Farm soil, go ahead and invest in something called Dolomite Lime or even Garden Lime. I would suggest getting pulverized so that it is readily available. Add a cup to 2 cups per 1.5 cubic feet of soil or regular size bag of soil. You will never have a cal mag issue again with this brand soil. This should fix your PH issues, it should just fix the soil. It did for me for sure. In fact this may resolve almost every issue you may ever have with FF soil besides user error.
Also, you are wasting time and money with the CO2 if you are exhausting the air. In order for CO2 to work effectively you need to have a completely sealed environment and the best thing you could do if you want to use CO2 is scrub the air. Meaning that you would have your filter on the floor of your tent sucking the CO2 back to the top and redistributing within the tent.
After further reading I also want to alert you to the fact that over use of sugar can be harmful and not beneficial to your plants. If you feed your plant a strong solution of sugar water, you create a situation in which the water outside its cells has a higher percentage of soluble material than does the water inside. The direction of osmosis reverses, causing water to exit plant cells or not be able to enter in the first place. The plant begins to die.
To me it sounds like you are trying to do too much and without more details it is hard to pinpoint exactly where the problem is occuring. Let me know if you would like more help…more details would be necessary but I could help you come up with a more stable routine if you were interested. Here’s some pics to show what i do…

You get the idea…this is all off FF

Hi Hans,
Sorry for the delayed reply back here as I’ve been tied up lately. Just wanted to follow up with you and let you know I’ll be responding back with a more detailed description on set-up, feeding, watering, etc.


Nice!! Looking forward to it…

Ff is as bad as mg my personal opp anyone with issues is useing ff ,try some pbp botanicare, and Cal mag botanicare, always nightmare when I see people and it’s 9 out of ten ff trio or dirty dozen I just stay away from anything fox farms and I’m no pro but I’ve yet to incounter a issue I use all botanicare products like a car … u use one product and it’s additives will all work together well mine has :v: and by the looks lock out pH start on the bottom and works it’s way uppppp so if in soil 6 -7 maxx dro 5.5 6.5 Maxx pH

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Also Auto flowers like the pro mix cocoa blend gives it a little more aeration for the roots to grow I did critical 2.0 to plant autoflower got a half pound return cured and dried

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And it was first time I grew a auto lol