Phosphorus or Calcium deficency? Advice?

[kilimanjaro]

Hi guys.

First grow here and as much as I would have liked my first post to be in the "Introduce yourself" area, it is not. But I will get to that part as well.

My first grow has been going well up until this point. I started seeing some dark spots on the leaves and reddish leaf stems. After some digging my conclusion is that the plant has some Phosphorus or Calcium deficiency.

Also, I'm using a crappy PH soil meter that a month ago was reading 6.0 to 6.5 and now I'm seeing 5. Watered only using distilled water and got another batch of it 2 weeks ago.
Regarding the watering part, what I think I may have done is water the plants a bit too early, not letting the first inches of soil dry up.

I grow in soil with coco mix (not only Coco! later edit) using ~30% perlite and use Biobizz nutrients.
I'll put some pics down below.

Any advice on how to deal with this?

 

[013]

Forget water strategy now you are in flower and it’s too late. Plus its not letting the top few inches dry, it’s waiting until it’s bone dry, light as a feather. When top few inches are dry - the bottom is still very much wet. But this applies to soil, coco is not soil - it’s a hydro DTW or drain to waste format.

You are in coco, which is inert, there is nothing in coco to feed your plant - it must be bottle fed. Coco needs feeding meaning water with light dose of nutes every day or every other day, no plain water. Are you using cal-mag? It’s very important especially in coco.

Shoot a full pic of that probe and post it here please? Then take that meter and set it aside. That’s not how to check ph of your soil, hell I don’t think it’s remotely accurate in water either. Runoff ph does not matter either. You take ph of water 15 minutes after nutes have been mixed in and adjust it before giving to your plant.

Are you adjusting ph of your water? What are you setting ph at? Again coco is hydro not soil. I'm focusing on that probe here again too - you need to get a ph pen that probe is probably not gonna cut it.

more folks will jump in soon wait to see what other replies you get.

 

[NuttyProfessor]

wow wow wow , i am shocked this plant got this far distilled water only in coco , and a higher ph , , you got away with a heap of things lol fair play
you need to start a feed of a good base nutrient with some cal/mag 50 % strength will do but water twice the pot size to fill her with brand new fresh feed , you also need a ph pen , 5.8 to 6.0 is ok , 5.6 early veg , make sure you add the cal mag ten to 15 mins before the rest , she is gonna starve soon if you dont give her the right ph and the right nutes , so far id say your a lucky pants

 

[NuttyProfessor]

so basically you have been feeding with acidic nutes , so you started around 7 as coco is about that and your water will be also , as you feed you lowered the ph slowly, now your out of the right rage, your plant cant take up any food

go by the left side HYDRO

 

[013]

BTW’s Welcome Kila, sorry to jump right in there but yeah glad Prof was not lecturing elsewhere today! Seriously you are lucky to have gotten this far, better heed advice tho and get her squared away quick, shits about to get real in flower.

 

[NuttyProfessor]

@kilimanjaro


Yes a big welcome , another thing on the diagnosing deficiency you were right , your gonna be a natural , look how far up you dropped out of (p) on the chart and you just dropped out of cal

 

[kilimanjaro]

I'm sorry for the confusion guys, my medium is soil mixed with coco, not 100% coco.

So, after reading a bit more myself and taking into account that i grow in soil (mixed with coco), was thinking of getting some Cal-Mag and add it to the feed along side with lowering the Nitrogen. For measuring the PH, I'll get a pen.
But I also want to hear some other thoughts, as I'm not 100% sure.

Also, here's an overview of the plants. Only the large one (Amnesia CBD) has this issue.
Greetings fellow growers!

Aand here's a pic with the crappy thing:

 

[013]

Roger that! Great plan cal-mag yes. Thanks for pic yes do yourself a favor and replace with a pen. Gonna need calibration fluid high 7 & low 4 plus storage fluid too don’t let bulb dry out. Save that old one for roasting marshmallows!

what kind of soil mixed with coco? But most likely it’s still gonna be hydro rules apply like Prof described but tell us anyway

 

[kilimanjaro]

First of all, thank you guys for your willingness to help!

Regarding the soil, by looking on what is says on the box it's basic plant soil that contains peat, coco fibers, clay and limestone + 30% perlite. Also added some pics.

 

[farside05]

First of all, thank you guys for your willingness to help!

Regarding the soil, by looking on what is says on the box it's basic plant soil that contains peat, coco fibers, clay and limestone + 30% perlite. Also added some pics.

Peat, coco, clay, lime, and perlite would make your growing media a "soil-less mix". The lime buffers the growing media to the proper pH. Ditch the meter. You don't even need to be concerned with what the pH is of your feed solution. Don't fret "purple stems" either. There are plenty of strains that have a natural coloration to the stem. It's very rare to find a Phosphorus deficiency. Plants use very little of it to begin with. Overall they look pretty good. I don't see rust spots typical of Calcium deficiency. Your little bit of dark color on the few tips may just be over watering. Let them dry a bit more between waterings. Don't fear the N either unless you get tip burn. You'll know when you are feeding too heavy of N when the tips of the leaves turn a translucent color and then go from that to burnt.

 

[kilimanjaro]

Yep, will leave a few more days between watering from now on.

What got me a bit worried was the black spots on the buds.

 

[NuttyProfessor]

I always ph in a soilless medium ,
When i feed at a ph of 5.6 i am in the right range , the lime takes LONGER to activate so it brings your ph through the feeding range as the soil dries out , if you constantly add a high ph your medium will be high also , (every one to their own )
What is lime? Lime is a soil amendment made from ground limestone rock, which naturally contains calcium carbonate and magnesium carbonate. When lime is added to soil, these compounds work to increase the soil's pH, making soil less acidic and more alkaline. so adding a higher ph your out of range big time
also i don't like the sound of clay , it locks up (P)

 

[farside05]

Lime is added to soil-less mixes to raise the pH of the peat that is included. Peat has a pH around 4.0-4.5 and the makers balance the mix closer to 5.8. It takes about 3 days for the lime to balance out the mix once it's first watered. The pH of the feed has a miniscule effect on the pH of the substrate. The alkalinity of the water and the composition of the fertilizer you use has 100x more impact. If you use a fertilizer that has predominantly Amonical Nitrogen for the source of Nitrogen, it will drive the pH of the substrate down. If you use a fertilizer that is predominantly Nitrate Nitrogen, it will drive the pH up. Generally speaking, the included lime will work to buffer the substrate and keep it in the optimal range for about 6 months of use. After that you'll see a swing in the direction based on the Nitrogen type used.

 

[NuttyProfessor]

well looks like we get away with high or low then lol, , ill stick to what im doing at my lower ph , gives me something extra to do . it also depends on the peat ( lots are different ) Canada is the most acidic from what i read , i use Irish,, thanksw for the info , i always thought it worked different in pots , i thought when you threw in acidic nutes the lime took a while to kick in to raise the ph back up ,
I was going by promix as its well known
Promix recommends ph of 5.8-6.2. ... I would follow proper mixture instructions for your solution, let rest for 45 min or so, then adjust ph to between 5.8 and 6.
I perfectly understand you now

 

[farside05]

ProMix does buffer their product to that pH range but will tell you its not necessary to adjust your nutrient solution pH. InTheShed has a thread with conversations with the ProMix rep on the subject located HERE. I believe they also cite excerpts from the Bill Argo, ,Ph D (Blackmore Company) articles in their responses. I have that 5 part series on my Google drive that I can share if interested. Heavy reading but it goes into water, fertilizers, substrates, etc. Now will it hurt anything if you adjust it to 6? No, the media is going to buffer it anyhow. Its just an unnecessary step if you don't want to spend the time or money on doing it.

I used to pH my nutes too. When the topic came up, kinda slapped myself. My family owned a greenhouse/garden center that I grew up in and worked at from age 9-26. Couple acres under glass. We grew in a lot of ProMix/Sunshine Mix/Baccto. Water was city water, no fancy RO, large injection fertilizer system. You'd make 55 gallons of fertilizer concentrate at a time and the system would dilute it and add it to the flow that came out a standard garden hose. No way we were going to try to pH 1000's of gallons of water/fertilizer per day. Didn't have to. We tend to baby our plants and try to control things that we don't need to control. I have fairly average water, 7.9-8.1 out of the tap, 140ppm. After adding nutes it comes out to about 6.5-6.6. Using a fertilizer that is predominantly Nitrate Nitrogen (which if anything would drive pH up over time). Ditched the pH pen 2 years ago after all these conversations with reps and reading and haven't looked back.

 

[NuttyProfessor]

I cant read to good I'm afraid lol hence getting confused so much , but the way you explained they use it to get the ph in rage makes sense now , be pretty cool though if it worked how i seen it

 

[kilimanjaro]

So, bought today some Advanced Nutrients Cal-Mag and ordered a PH pen along with 4 mini Hygrometers to put in the jars when curing.

Will wait a day or two for the medium to get dry and was thinking to water only using Cal-Mag and some Biobizz Alg A Mic. What do you guys think, sounds like a plan?