Leaf Spots, Rusting, Wondering What It Is

[mrking]

Hi,

I am not overly concerned with these spots but being new to growing cannabis it would be good to learn from it. Plant is really healthy besides these three leaves.

I am thinking maybe the start of calcium deficiency?

The plant is on its 57th day from sprouting in Pro-Mix soil. Re-potted with Pro-Mix soil into a 3 gal fabric pot some time ago.Lite nutes given 6 days ago, 10 cups from a mixture of: 5 gal water, 2 tbs epson salts, 1ml Micro, 6ml Flora, 1ml bloom from General Hydroponics ph'ed to 6.4. It is on three lower fan leaves, with one fan leaf being a little more yellow than the rest. Not sure if spots were there before watering with nutes.

Plants go outside during the day and come in at around 6 to finish under an Mars Hydro SP150. Plants to go outside fully at the end of the month. Looked for insects but nothing. We have an ant issue right now, so I sometimes find them on the plants after I bring them inside. I kill em when I find them. No aphids.

It's a Harlequin high CBD strain that seems to leaning towards an indica.

Would be good to hear from those that have seen this.

 

[AdaminCO]

Okay, so first off, the GH nutrient line you’re using is made for soilless (coco) or hydroponics.

If you’re in coco, you need to be going in at 5.8-6.0.

I see this issue a lot with folks using it in soil. I think you need the entire “Performance Pack” if you’re going to use it in soil. If you look at their feed schedule, it only calls out recirculating or drain to waste systems which are hydro.

 

[bluter]

Okay, so first off, the GH nutrient line you’re using is made for soilless (coco) or hydroponics.

If you’re in coco, you need to be going in at 5.8-6.0.

I see this issue a lot with folks using it in soil. I think you need the entire “Performance Pack” if you’re going to use it in soil. If you look at their feed schedule, it only calls out recirculating or drain to waste systems which are hydro.

Pro-mix is considered a hydro media. ph rules are different, but it is essentially hydro. hydro is any media where you need to supply all, or the bulk, of the nutrients required to grow the plant.

pH Chart

• MagicJim
• Oct 5, 2017

there is nothing wrong with the op's nutes. he using one of the most common combination of media and nutes out there.

looks like a mild hunger / slight pottasium def with maybe a bit of splash burn. or maybe mag def - my read is terrible on mild stuff.

@Emilya could probably nail what it is for certain.

 

[The Celt]

Hey @AdaminCO , depending on the type of ProMix he’s using, it’s only buffered peat with perlite, and maybe so mycos but no nutrients, would that not be the same idea as using coco.

I know quite a few growers that use liquid nutes this way, not GH specifically though.

 

[mrking]

Gotcha. Rookie mistake it seems. I’ll see if I can find info in using it in soil for the time being.

I am in soil and won’t be switching to coco so I’m stuck with what I have.

The water mix was less than 1/4 mix of what GH recommend for drain to waste during veg, so hopefully I am safe.

Knowing now what you told me, any idea what the issues with the leaves is?

 

[bluter]

to the OP - are you using HP or potting pro-mix ? potting promix has time release nutes and is not really recommended for cannabis indoor.

 

[mrking]

Pro-mix is considered a hydro media. ph rules are different, but it is essentially hydro. hydro is any media where you need to supply all, or the bulk, of the nutrients required to grow the plant.

pH Chart

• MagicJim
• Oct 5, 2017

there is nothing wrong with the op's nutes. he using one of the most common combination of media and nutes out there.

looks like a mild hunger / slight pottasium def with maybe a bit of splash burn. or maybe mag def - my read is terrible on mild stuff.

@Emilya could probably nail what it is for certain.

Edited** using the ProMix potting soil mix which is different from the other ProMix.

 

[mrking]

to the OP - are you using HP or potting pro-mix ? potting promix has time release nutes and is not really recommended for cannabis indoor.

Ah, using the potting mix ProMix. So essentially I don’t have to use any extra nutrients?

 

[AdaminCO]

Pro-mix is considered a hydro media. ph rules are different, but it is essentially hydro. hydro is any media where you need to supply all, or the bulk, of the nutrients required to grow the plant.

pH Chart

• MagicJim
• Oct 5, 2017

there is nothing wrong with the op's nutes. he using one of the most common combination of media and nutes out there.

looks like a mild hunger / slight pottasium def with maybe a bit of splash burn. or maybe mag def - my read is terrible on mild stuff.

@Emilya could probably nail what it is for certain.

Ah... this I did not know. I always assumed @InTheShed was in soil. Doh!
I did say “if you’re in coco” lol.
He does need to drop he pH though.

 

[bluter]

OK, so I wasn’t totally out to lunch. Phew. Thanks!!

ph according to chart.

Ah, using the potting mix ProMix. So essentially I don’t have to use any extra nutrients?

you will likely need them. the trouble with the potting mix is you'll never know what you are getting and when. can throw the plants in to all sorts of trouble through the entire grow, and make fixing it more difficult.

 

[mrking]

ph according to chart.





you will likely need them. the trouble with the potting mix is you'll never know what you are getting and when. can throw the plants in to all sorts of trouble through the entire grow, and make fixing it more difficult.

It will make my first grow interesting then. lol

I always ph between 6.3 and 7. Usually around the 6.5 mark but today’s was 6.4. Looks like I’ll need to do a couple of watering at 6.6 or 6.8.

 

[Emilya Green]

looks like a magnesium deficiency to me, being on the lower leaves. Ca shows up on the upper leaves since it is a non mobile element. You need to be a lot more accurate with your pH... 6.3 is where you want to nail it, every time. You do NOT need to do more waterings at the high end of the scale, for with any drift at all, your nutrient mix would almost immediately be out of the usable range.

 

[mrking]

looks like a magnesium deficiency to me, being on the lower leaves. Ca shows up on the upper leaves since it is a non mobile element. You need to be a lot more accurate with your pH... 6.3 is where you want to nail it, every time. You do NOT need to do more waterings at the high end of the scale, for with any drift at all, your nutrient mix would almost immediately be out of the usable range.

Gotcha. Knowing your rep in these forums I appreciate your time looking at my issue. Thanks!

In terms of using GH nutrients with theProMix potting soil should I stick with only using it at 1/4 of their recommended recipe?

GH Flora Feed Schedule

Right now after a feed, the plan is for the next two waterings to be just water, which I will now ensure are ph’ed to 6.3. Does the seems like a good plan?

These plants will be outside permanently next Monday

 

[Emilya Green]

Gotcha. Knowing your rep in these forums I appreciate your time looking at my issue. Thanks!

In terms of using GH nutrients with theProMix potting soil should I stick with only using it at 1/4 of their recommended recipe?

GH Flora Feed Schedule

That seems to be the common advice when using these nutrients in soil, especially if you are watering with nutes every time as you would in a hydro grow. If you are running like soil, where you water with nutes one time and water only on the next pass, using soil as the buffer it is intended to be, you could probably get by with 1/2 dosage.

 

[mrking]

That seems to be the common advice when using these nutrients in soil, especially if you are watering with nutes every time as you would in a hydro grow. If you are running like soil, where you water with nutes one time and water only on the next pass, using soil as the buffer it is intended to be, you could probably get by with 1/2 dosage.

Much appreciated. I’ll give that a try next feeding and see why happens. Worse case, I’ll go back to 1/4.

 

[Emilya Green]

Please know that a little bit of tip burn is actually desirable. People these days have lost sight of the fact that we are attempting to fertilize our plants, to run them right up to the limit, not just simply feed them. If you aren't at least burning the tips, you are not trying hard enough.

 

[Emilya Green]

Right now after a feed, the plan is for the next two waterings to be just water, which I will now ensure are ph’ed to 6.3. Does the seems like a good plan?

These plants will be outside permanently next Monday

Where did this idea of two rounds of water only come from? Water/fertilize/water/fertilize... all the way through the grow. The reasoning is, strong nutes on one pass to supercharge the plants... then on the water only run, the plant is able to use any unused nutes from that last pass, cleaning out the soil of any excess nutes. It is a good system. Two plain watering times would definitely clean the soil, but probably too much. That would put you back in just feeding territory, and not exactly fertilizing and trying to give the plants a boost.

 

[mrking]

Where did this idea of two rounds of water only come from? Water/fertilize/water/fertilize... all the way through the grow. The reasoning is, strong nutes on one pass to supercharge the plants... then on the water only run, the plant is able to use any unused nutes from that last pass, cleaning out the soil of any excess nutes. It is a good system. Two plain watering times would definitely clean the soil, but probably too much. That would put you back in just feeding territory, and not exactly fertilizing and trying to give the plants a boost.

No idea, I have read it or saw it in a video from more than one source but cannot remember where exactly. Before I found these forums though.

Having said that, these forums and your input is making my life easier. Thank you!

 

[CanadianJim]

to the OP - are you using HP or potting pro-mix ? potting promix has time release nutes and is not really recommended for cannabis indoor.

I used it for indoor grows for years. Never had a problem. I used the organic herb & vegetable mix, though. The flowering plant blend is really high in nutrients, I would only ever use it as a top dress.

 

[cannanewb]

It will be a challenge definitely. You may require Cal-magic. It is needed for fast growing plants like cannabis. I have grown a strain that could not handle nutes. I have always used pro mix in outdoor raised beds with no problems. Switched to sunshine mix this year. Typically at about two weeks old they should be able to handle 1/4 strength nutes. Right now just waiting to go outside about 40 days old and they receive 4ml Calmag - 3ml grow, 2ml micro, 1ml bloom per gallon and that will go up further when they get huge.