Leaf Rust - Mag/Phosphorus or mold?

Hey Guys,

First time grower. Have gone threw the over watering process, let the plants dry out completely flushed them w R/O. Then gave them some light nutrients. All organic Vegamatrix nutrients - organic soil with perlite/vermiculite at bottom of pots. I believe I made the mistake of not mixing the perlite into the organic soil bc I feel as though the roots aren’t getting enough oxygen. I’m also supplementing with CO2 when I’m able to get a tank. I have no idea what the rust is or where it’s coming from. It doesn’t appear to be mold but the leaves are just slowly dying randomly so it may be. Idk. Help! Also, let me know what more info you need.

Pics in normal light are definitely needed here.

I'll venture a guess that root problems are giving pH issues. Overwatering. Flushing, especially in poorly aerated soil, is ridiculous .

It seems there is a lot of confusion and misinterpreted expectations on flushing soil. Soil isn't coco or some other inert medium. It doesn't respond like an inert medium and it's not so easily rid of the nutrients and elements that make it up, nor is it easily corrected by running water through it. By running large amounts of water through it, especially a poorly drained soil, you're just digging your hole further down. I would also note that perlite is great for aeration (ie Oxygen), it's the vermiculite that holds more water than not. Perhaps you have too much in the bottom of the pot inhibiting your drainage? Never the less, short of repotting into something better drained your best bet is to just buckle up for the ride. Soil is like a marriage. Once you say 'I do', it's hard to get out of that mess. Coco and other inert mediums are like a girlfriend. If she get's out of hand you can easily kick her out.

You’re absolutely right. I think this weekend I may grab some perlite and repot them in the same pots; if you think I can get away with that and it’d help. Like I said this is my first soil grow and I’m an idiot. The new growth is lush and green with only slightly burnt tips so I’m pretty sure it was just nutrient burn. But thank you for all the tips guys. Keep em coming.

Dazed540; don't think you have a monopoly on being an 'idiot'. We all have pantries stacked to the rim with this shit...haha. If your new growth is lush and green, maybe it's best not to do anything, except stay the course. Plants (all plants) are super adaptable...I mean super adaptable. If they can grow through their problems, they will.

Just stop overfeeding and do not flush. Do not flush. Even at the end of flower do not flush. It's totally impossible.

How much are you feeding and what exactly are you giving? What exactly are you growing in? Is it 'true' soil, or peat moss? To me, this looks like a textbook potassium deficiency! You may have an issue with sulfur as well, but that burning on the margins and tips, seems to be related to lack of potassium! In the 3rd pic you posted (5b8c...) you can even see the plant out of focus on the top right, is already starting the deficiency as the margins are paling, and will ultimately burn as it loses potassium.

Ok here’s some updated info:

* Strain; Strawberry cough
* Soil in pots w a Soil pH approx 7.5.
* System type - Vermivulate/Perlite mix at bottom of organic soil mix.
* What is strength of nutrient mix? N/A - will be soon.
R/O Water often has difficulty determining pH if it’s truly 000ppm until something is added to it I’ve found. Otherwise my meter (which has been calibrated) indicates pH as anywhere from 3.8 to 8.3, though generally more acidic.
* Indoor 5x5x8 Tent
* Light system, 1200W (600 True Watts) VIVASPECTRA LED w/ Bloom and Veg Switch’s
* Temps; 65-80F
* Humidity; 44 Day, 64 Night
* Ventilation system; Yes, AC Infinity CLOUDLINE T6, Quiet 6” Inline Duct Fan with Thermostat Speed Control -
* AC, Humidifier, De-humidifier, - All three.
* Co2; Yes, - @ approx 1000-2500ppm.

Also, is CalMag something I can (or should) apply foliarly? My plants have seemed to have dried out at this point and I’m showing a soil pH of 7.5. I’m just going to wait until they tell
me they need water before watering them again.

However, when I do: What would you guys recommend?

R/O pH adjusted water or just plain old tap water with a reasonable TDS?
Or a very light nutrient solution added?

I use Vegamatrix Amp-it/Boost/Grow/Bloom/Big n Sticky (in varying degrees depending on plant stage development) and Great White Mycorrhizae. I’m planning on letting them recover for a bit and then putting them right into flower. Please - let me know what the ‘collective’ recommends.

Recommendation; stay the course and go with your gut. I can't comment on the CalMag, as I add Ca and Mg separately. I'm sure the bottle has some directions on it and recommendations as to how it can be applied and at what strength. Those who use R/O water swear by it, and those who use tap, say no worries. I use my tap water...I have no idea what its make up is..but it works for me. Without being able to compare them both, under the exact variables, I couldn't tell you which one is best. Just being honest. I think you'll do fine...don't sweat it.

Tap water should work just fine, as you said, with a reasonable TDS. If you use tap water, you also (typically) don't have to worry about adding cal-mag. Soil grows also tend to need cal-mag supplements far less often than mediums like hydroponics and aero grows. In my opinion, you don't need RO unless you're doing a form of hydroponics or such. It sounds like you've done good, as Canna said, keep going with your gut as you have. I've read that Strawberry Cough can be on the tougher side to grow, awesome for a first grow with a tough strain!

Thanks for all the support guys. I really appreciate it. The soil is a very looose unfertilized mixture of organic soil from a local farm - with a ph of above 7 according to my cheaper tri-meter. Not sure of the exact make-up. Just wanted to stay as organic as possible really hence the vegamatrix nut’s line-up. Not to mention I’m trying grow Kushmans strain and it seems the concensus is the taste and smoke is best in organic soil w organic nuts. The biggest downside being time lost and the potential final harvest boosts of hydro/aero obviously. My big mistake was using vermiculite instead of perlite; and only at the bottom for drainage instead of mixed homogeneously through out as well as the bottom. That and going overboard on nut’s. I’m feeding them tomorrow, after about almost two weeks - with a small amount of cal/mag and Veg. Anyone have a better suggestion? And also, what is a max TDS I don’t want to exceed (generally) - to avoid nut lockout and such...

Let me know if there’s a place one can chat about this In real-time also...

I’m feeding today - half the water and nut’s I usually use as well as omitting the vegamatrix ‘boost’ for CalMag. Again, I’ll test the ph and bring it to around 5.8-6.3 and try and keep the TDS as low as possible w RO Water I just put a double DI Filter on. Let you know how it goes. This soil sucks at absorbing the water quickly; so as I’ve let these plants dry out - the soil has withdrawn from the sides of pot. I’m just going to try and pour the water down the sides as well as directly over the root ball this time. Wish me luck.

TDS 409
Ph 5.65
5ml CalMag
5ml Grow 5-2-3
1 Gal - .25 gal per plant.
22 Qt pots w soil that tends to compress; so I’m not trying to over water - usually I use .5 Gal per pot. If they respond well I will try more volume a little at a time as they absorb the water/nut’s.

Logan Burke said:

Tap water should work just fine, as you said, with a reasonable TDS. If you use tap water, you also (typically) don't have to worry about adding cal-mag. Soil grows also tend to need cal-mag supplements far less often than mediums like hydroponics and aero grows. In my opinion, you don't need RO unless you're doing a form of hydroponics or such. It sounds like you've done good, as Canna said, keep going with your gut as you have. I've read that Strawberry Cough can be on the tougher side to grow, awesome for a first grow with a tough strain!

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Yes you are correct about the R/O. The only reason I actually have it so that I don’t have to clean my humidifiers all the time (Scaling) . However, it’s also great way to keep the TDS down and perhaps avoid some nutrient locked out - so I’m told. I’m going Hydroponic my next grow - I wish I knew more about making good soil but so far all I the issue is there are typically power outages 3-4 times a year for as much as 2 days and in some areas 2 weeks even! I already have two 900W backup UPC‘s that handle all the short blackouts, but even then I’m taking they can only run it for about 5 fucking minutes. I’ll probaly buy a a separate UPC for the hydropumps at least - which I imagine could them for hours if not a day in that case.

Dazed540 said:

Let me know if there’s a place one can chat about this In real-time also...

Click to expand...

Or if anyone feels like FaceTiming and I could show someone in real-time the plants...