Help a first-time grower girl!

[Maggie2]

Growing indoor in a cabinet, good ventilation, 1 month old plants in miracle gro organic mix with lightly pre-fertilized SCOTT's perlite added to the mix.
fertilizer: No fertilizer has been used yet.
pH: between 7 and 7.3
Light: 400w MH
Temp: 77 to 82F
Water: I spray a pH neutral tap water with a couple of drops of SUPERTHRIVE added. Soil is always kept saturated but not overly soggy.

All has been going well but recently I started seeing a brown spot on one of the plant's old large fan leaves. The spot progressed and grew bigger. Now I see tiny brown spots on some leaves in both plants. also, slight yellowing shades on the leaves. I know it doesn't look very bad now but I'm worried it may progress to the point of no return, and I' afraid it will if i don't get to the bottom of it now.
As far as I can tell, no visible pests are found on or under the leaves.
Please HELP girl! Those were my only two seeds and I've been through hell and high water to get them!
Thank you so much!

 

[BudTester420]

Ill try and take a stab at this, im not great by any means but it might help.

I believe your ph should be around 6.7 with soil but i cant remember off the top of my head, you should also let your soil dry out some because roots like air. Usually you wait 3days or more in between waterings, people say to lift your pot when its dry then wet to feel the difference so you know when to water.

The spotting on the leafs might be from the miracle grow, i think they got to much nutes from the soil early on but i could be wrong. Hopefully someone with more experiance can chime in.

Hope it gets better!

 

[dragontoker]

Ditto as above, PH should be 6.5 and you should let your soil dry out. If your plants/soil are at least 3 weeks old you could probably starting adding a light mix of nutrients to that soil, maybe even mix a half dose of calmag to your water.

I think the spots are from lack of nutrients because of your PH is locking certain ones out. Are you measuring with a digital PH meter?

 

[Halfbreed]

I'm new to this too, and had the same exact problem with my cuttings/seedlings. There's a lot of information on here, including sticky's that give photos of different problems, and while I'm still correcting my issues, I'm preeeeetty sure that it's a ph problem.

 

[Vampire]

Ahhh I grow in mg organic soil and love it; don't think its caused from that or else all the leaves would show browning. I'm inclined to think the superthrive your spraying them with caused it because the soil is feeding the plants enough for 4 weeks and foliar feed is overkill when they're young. Also, once you start feeding them from the soil, start with 1/4 the recommended amount on the label of the ferts and built it up little each time til you reach the full amount. If they were mine I wouldn't feed em anything for a while; those leaves are a healthy green now and I'd just water regularly, maybe skip foliar watering for a while and watch the leaves color; if they get a little lighter green, then start food, either by foliar or soil but not both. Rastafari.

 

[bucktoothal]

Hello
Your pH should be no more than 6.8, Get your pH down somewhere around 6.5- 6.8. you should also stop foliar feeding till the problem corrects its self.
Hope this helps

 

[QueenTokelove]

It sounds like everyone has given good advice. Like everyone else, you do need to lower your ph. What are you going to use to lower it? I use distilled white vinegar mixed in with some calmag. When my ph was off it cause my plants to have brown spots due to a calcium/mag deficiency. The calmag corrected it. Just my added 2 cents.

 

[Maggie2]

Thank you so much everyone for your helpful suggestions. I checked on the plants today and the problem in progressing as I feared :-( I'm going to lower the pH with some plain water with distilled white vinegar added for now and monitor the plants for the next couple of days.
I gather from your suggestions that what I have is under-fertilization issues rather than over-. pH is locking the nutrients out (?) I wanted to make sure before I proceed. i don't want to over-fertilize and create another problem, or under fertilize and starve the plants
I'll keep you posted..
Thank you again!

 

[QueenTokelove]

If the brown spots don't clear up then I would suggest using the calmag. Keep us posted.

 

[Maggie2]

It's spreading and it's destroying both plants!!!
I corrected the pH and added 1/4 the recommended amount of fertilizer. But now I'm suspecting it could be some sort of fungus. I see new healthy shoots constantly growing, although more slowly now. The rust spots are spreading quickly on large old leaves.
Humidity is near 40% so it's not really damp in there. But could it be that the Miracle Gro soil I'm using was harboring fungal spores that spread to my plants? anyone had similar problems? How should i proceed??? Hope I can get some expert opinion on this.

Thank you guys!

 

[QueenTokelove]

Wow, sorry to hear that you are having problems. I am a novice grower but I will try to share what was given to me. First off, did you try using some calmag? But it also kinda resembles a phosphorus deficiency...But don't hold me to that..Have you tried this link:

Cannabis Plant and Pest Problem Solver - Pictorial

I really hope someone with more experience than myself will chime in here....Maybe I can ask a few folks to come check your thread out.

 

[Maggie2]

Thank you for the reply! I ordered some Calmag but it will take a couple of days to arrive. Do you recommend something similar I can get at the garden center or at Lowe's?

 

[dragontoker]

This is what I would do cause I dont know the makeup of your tap water. I would flush the crap out of the soil with either RO or distilled water @ the proper PH. Then I would water again with the proper PH water, same thing RO or distilled but this batch would have calmag and a half dose of nutes. The next watering would be when the soil is dry but I would continue to use RO or distilled with calmag added. Alternate watering and feeding. Last but not least, I would remove the bottom leaves that are sick, they wont get any better.

You never mentioned what your tap water contains. If you dont know, dont use it.

 

[dragontoker]

Looking at your plant very carefully, your new growth tips look like they are getting a little nute burn. This would be another good reason to flush as I stated above.

 

[QueenTokelove]

Thank you for the reply! I ordered some Calmag but it will take a couple of days to arrive. Do you recommend something similar I can get at the garden center or at Lowe's?

I would do what Puff suggested and flush your plants while you wait on the calmag to arrive. After you flush it will take a few days for it to dry out again so maybe by then your calmag will have arrived. Don't run out to Lowe's just yet.

 

[Vampire]

Thank you for the reply! I ordered some Calmag but it will take a couple of days to arrive. Do you recommend something similar I can get at the garden center or at Lowe's?

Yeah, epsom salts is cal/mag or domolite lime; lime in Lowes, epsom in grocers or pharmacal stores.

 

[Maggie2]

Thank you! How much epsom salt should I use?

 

[QueenTokelove]

Yeah, epsom salts is cal/mag or domolite lime; lime in Lowes, epsom in grocers or pharmacal stores.

Totally forgot about this.

 

[Halfbreed]

Ok, based on the bit of knowledge that I've gained from here, I would say that a) you should definitely trim off the older affected leaves; b) test your runoff and use an electronic liquid tester to calibrate your distilled water to a ph of 6.5 using a ph up or ph down supplement; and c) DONT add any more nutrients until AFTER you are sure your ph problems are corrected. You don't add nutrients because with an improper ph your plant locks out any uptake and the nutrient levels in your soil build and become, for lack of a better term, salty and therefore toxic to your plant. I had a very similar problem, flushed out my soil with ph correct water, and my plants came out strong and are now growing like weeds, excuse the pun. I noticed that when I corrected the water they showed signs of nutrient burn for a bit because they started finally taking in nutrients, so I'm just continuing to use nothing more than ph correct water until the signs of nutrient burn fade and I feel I can start feeding them a bit at a time. I would take the time to read the sticky's in the grow room forums, there's TONS of good information there, including pictures that show different problems so you can better identify your plant's issues. Also, message some of the other growers who use things similar to you so you can find out what kinds of problems they've had and how they've corrected them. There's no substitute for asking the right questions to people with life experience.

 

[SmokzAlot]

Yeah, epsom salts is cal/mag or domolite lime; lime in Lowes, epsom in grocers or pharmacal stores.

Basics

Epsom is magnesium and sulphur
Dolomite Lime is Calcium and Magnesium
Gypsum is Calcium
Calcium pills at the discount store ground up will do in a pinch.