Brown spots and yellowing leaves

[JayM]

Hi there,


I transplanted my small plants 2 days ago and have noticed slight yellowing and brown spots appearing on the lower fan leaves of my plant. My other, smaller plants seems to have drooping leaves.

From what I have researched it could be a Calcium deficiency or overwatering. I think I may be overwatering them.


Can someone take a look at these photos and let me know what you think?


What is the general rule for watering? I have seen that I should wait until the top inch-ish of soil is dry before I water?

Thank you,

 

[Pbass]

Hi @jayy I think your assessment is correct. Looks like they are looking for that extra cal/mag, and weed plants seem to handle it well, so I'd start it in with my water. Also look too wet. There's a great piece by @Emilya for good watering habits, it's linked in my signature below. Dry only an inch down could still (and probably does) mean soaking wet at the bottom. Weed plants like a good dry cycle, let them go till the weight of the pot seems dry as a feather between, otherwise you are going to get root rot and lockout. I'd guess you may have a bit of that now. Have you measured the pH of your water and soil? CHeers mate, good luck, don't worry they definitely look strong still...keep us posted and we got your back. Smart folks to follow!

 

[JayM]

Thanks so much for the reply Pbass. Will check out that post about watering right now. I have checked the PH of soil and was just below 7.0. I will start giving them some cal/mag too.

 

[Emilya Green]

Please get out of the habit of adding something every time you see a problem. Too much Ca and Mg in the soil can easily lock out other things that are needed... don't give supplements until you are sure that you need them.

I believe that given a proper wet/dry cycle, these plants will recover and do well... you may lose the lower set of leaves since they have already been tagged for destruction, but by starting now to properly dry out the lower roots between waterings, the rest of the growth should be fine. Save the calmag for when the actual signs of needing it appear.

 

[JayM]

Thanks Emilya.

My gut is telling me it is mainly a watering issue. This is my first grow + being home for covid lockdown, so I think I am obsessing over my plants and checking on them constantly so I think I must be accidentally giving them too much water...

Maybe I will hold off on any additives until I allow my soil to actually dry. I was going to start the general hydroponics flora nutrients sometime this week, maybe I should hold off on that too?

 

[Emilya Green]

Thanks Emilya.

My gut is telling me it is mainly a watering issue. This is my first grow + being home for covid lockdown, so I think I am obsessing over my plants and checking on them constantly so I think I must be accidentally giving them too much water...

Maybe I will hold off on any additives until I allow my soil to actually dry. I was going to start the general hydroponics flora nutrients sometime this week, maybe I should hold off on that too?

yes I would hold off because you don't usually need nutes already in new soil, but nothing is stopping you from trying to supercharge a health plant with nutes this early... but you don't have a healthy plant, so wait a bit. What soil are you in?

Why did you choose general hydro nutes in a soil grow, or is this maybe coco and not soil? Are you working from advice given by the local grow shop? So many new growers are getting bad advice these days, either from aggressive sales people or the internet... its really one of my pet peeves.

 

[Pbass]

Thanks for joining @Emilya that's why I tagged you! I have read in various places that weed can take extra cal/mag and indeed seems to need extra under LED. I use it like I use my pH additive (vinegar), which 1.5tsp is in every gallon of water I serve, with nutes or not. Regardless, seems like @JayM was on to it, has some good intuition eh? Glad you could confirm for us. CHeers!

 

[JayM]

My soil is:
- 60% Soil from local garden centre (screened peat, topsoil, natural compost)
- 25% perlite
- 15% blend of worm casting and peat moss compost

I read Jorge Cervantes book and have been researching the rest on the internet. I bought general hydro because their products say they can be used in soil as well and I planned on diluting them to half what was called for. I plan on growing outdoors in early May and have started these ones inside.

 

[JayM]

Just checked the PH of my soil for the first time in about 5 days and it has jumped up to 7.5 or even over that! Does this make sense? A combination of alkaline soil and too much water?


Thanks

 

[Emilya Green]

Just checked the PH of my soil for the first time in about 5 days and it has jumped up to 7.5 or even over that! Does this make sense? A combination of alkaline soil and too much water?


Thanks

To correctly test the base pH of your soil requires a slurry test, and to do it right it must be done in a vacuum. If you didn't do that, don't trust the reading you got on your soil pH.
Soil pH should be up near the upper end of the soil pH range of 6.2-6.8 pH. It does not adjust itself with a couple of waterings or with "too much" water.
If you are giving nutes that are EDTA based (salt based) then you do need to adjust the pH of your incoming fluids to 6.3, or where mathematically the most nutes are the most mobile in soil. If you are not yet giving nutes, there is no need to adjust your pH. As long as you make sure that the incoming fluid is at the proper pH, you need to do nothing to your soil... just let it drift the pH of your fluids up to the base pH as the soil dries, and your nutrients will all become mobile in turn.

Regarding the Cervantes book... there is a lot of good info in there but in the 40 years since that book was written, we have learned a lot more and discounted a lot of the ideas you will find in that book. There is a reason we grow better pot today than they did back in the 70's.

 

[JayM]

Hmmm ok thanks a lot. Looks like I have a lot to learn.. I guess I will just let them dry out a bit and try to get into a proper watering cycle before trying to change anything...


Thank you Emilya