New grow, same defiencies

I can't figure this yellowing my plants get. It's almost every plant does the same thing. The lower green leaves start to show just a little yellowing then brown spots then it gets worse and looks like the photo I'm attaching. Ive checked the threads on here and tried a few things but it doesn't seem to be helping. The only thing I can think is my soil ph is off but depending on who u talk to that doesn't matter. I started this grow off with my water and nutes at 6.4 and 6.5. I fed yesterday with my nutes at 6.5 and the run off tested at 5.8. My last grow this was the same, so I adjusted a little bit, but the only way I could get my soil ph up to 6 was ph'ing water and nutes to around 7. What do u think. My last grow I only had 1 beautiful plant that didn't show any biting or defiencies, and I got 4.5 oz from that. The others were averaging 2.5. Same nutes, different strain. Thanks for the help. Oh I'm 40 days into veg using floranova series, with promix hp soil

Dan9812 said:

I can't figure this yellowing my plants get. It's almost every plant does the same thing. The lower green leaves start to show just a little yellowing then brown spots then it gets worse and looks like the photo I'm attaching. Ive checked the threads on here and tried a few things but it doesn't seem to be helping. The only thing I can think is my soil ph is off but depending on who u talk to that doesn't matter. I started this grow off with my water and nutes at 6.4 and 6.5. I fed yesterday with my nutes at 6.5 and the run off tested at 5.8. My last grow this was the same, so I adjusted a little bit, but the only way I could get my soil ph up to 6 was ph'ing water and nutes to around 7. What do u think. My last grow I only had 1 beautiful plant that didn't show any biting or defiencies, and I got 4.5 oz from that. The others were averaging 2.5. Same nutes, different strain. Thanks for the help. Oh I'm 40 days into veg using floranova series, with promix hp soil

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Although your yellowing looks a bit different than what troubled me for awhile...the timing is right and I am in HP or similar also. I know nothing about floranova but the cure for me was starting epson salt at 1/8 tsp per gal. every water about mid veg.

From what I understand PH doesn't matter in organics. If your not growing organics then your root zone does matter and yours is likely below 5 for run off to be 5.8. That is a problem, you will be locking out magnesium, Calcium and in flower will see lack of potassium too. Not much point in adding cal/mag if the roots cant take it on board. I'm sure there are soil amendments to raise your root zone ph or flushing with a lot of PH7 or above water. I will have to research more to be sure on that though.

Edit Ok you have two main options, flush with 3 times the pot size of ph7 water or continue to water with ph7 solution. until eventually your root zone will balance out. I think I would be flushing to get it balanced quicker so the nutrient lock outs don't spread further. They may show signs of overwatering briefly but will pick up after the pots dry out. I assume that picture is not your plant, make sure they are draining out nicely and not sat in trays full of water.

A 3rd option would be soil amendments but I know almost nothing of those I'm afraid. Adding lime will lower the acidity or raise PH. Again I have zero experience on that matter.

are you using plain tap water ?

Yes plain tap water, tap water comes out at 7.2 ph, and 125 ppm. Maybe I will try doing the flushing to 1 of the them and see what it does. Both are grizzly purple kush. I water and let the run off sit in the trays but it's only in there 12 hrs or so. I fed yesterday at like 530pm and this morning all the water was gone. hopefully after flushing the root ph will stay up around 6. maybe try the other with epsom salt. Thanks for the replies

Dan9812 said:

Yes plain tap water, tap water comes out at 7.2 ph, and 125 ppm. Maybe I will try doing the flushing to 1 of the them and see what it does. Both are grizzly purple kush. I water and let the run off sit in the trays but it's only in there 12 hrs or so. I fed yesterday at like 530pm and this morning all the water was gone. hopefully after flushing the root ph will stay up around 6. maybe try the other with epsom salt. Thanks for the replies

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Runoff pH isn't really necessary to test, pH going in is more important. What medium are you growing in? Have you been feeding consistent amounts of nutrients? Looks like it could be nutrient burn.

I'm roughly 5.5 weeks into veg using promix hp. I have fed 3 times, 1 ml first feeding, 2.25 second and just yesterday 3.75 ml floranova grow

It doesn't look like nute burn at all. It would show on every tip of each leaf. It looks like a ph fluctuation problem which is why its in patches in a non uniform pattern here and there.
And run off is important if using liquid nutes. with soil or soilless

One important thing though, ProMix is a soilless medium not a soil. So its possible that putting in 6.4 ph is not ideal and a low ph would suit. Its coir and peat so roughly speaking its more hydro than soil. That would explain the symptoms you are seeing.

Plus I apologise for not picking up on that sooner, Its just you said soil so I was treating it as such. Same issue but the cause is more likely using too high ph in the first place rather than your medium been too low in ph

I had to read a lot of stuff on pro mix(cuz I'm all coco), they don't help the situation by calling it a soil on there own site but when you look at what it is made from its the same as Royal gold tupur or a coco mix which wants a ph in the hydro range. 5.5-6.2 ph would be good, don't stick to just one range, vary it lightly.

Dan9812 said:

Yes plain tap water, tap water comes out at 7.2 ph, and 125 ppm. Maybe I will try doing the flushing to 1 of the them and see what it does. Both are grizzly purple kush. I water and let the run off sit in the trays but it's only in there 12 hrs or so. I fed yesterday at like 530pm and this morning all the water was gone. hopefully after flushing the root ph will stay up around 6. maybe try the other with epsom salt. Thanks for the replies

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I wasn't going to comment because I really don't know so was just reading through your responses to see what I could learn. I just wonder, if you let them sit in the runoff and it is all eventually re-absorbed, aren't you introducing what you just flushed out back into your medium? I don't know anything about Pro-mix but I grow in coco and I think I have a lockout caused by salts in the medium, I used cheap coir and didn't wash it first, and I know salt build ups can be an issue in coco. I'm not suggesting that's what you're dealing with now and I'm sure someone will say if I'm wrong but might be something to think about, especially if you're going to be flushing them.

Wow I thought promix hp was soil, it doesn't feel anything Iike coco, so are you saying my ph'd water and nutes of 6.4-6.5 is too high?

The peat in promix will drive pH down to some extent, you shouldn't pH too low in a medium that contains it. Personally I'd stay above 6.

Alot of people who grow in promix ammend with lime for this reason.

Ok just to clarify are Resin are u saying to keep the soil ph above 6 or ph'd water above 6

If you haven't amended with lime, I'd keep your water going in above 6 for sure. Peat has a natural PH of about 4.5 so it will tend to drive root zone pH down.

@RM3 is about the most knowledgeable person I know on promix, maybe I can get him to chime in here.

Resinhound said:

If you haven't amended with lime, I'd keep your water going in above 6 for sure. Peat has a natural PH of about 4.5 so it will tend to drive root zone pH down.

@RM3 is about the most knowledgeable person I know on promix, maybe I can get him to chime in here.

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Yeppers, good advice, I add lime and use 5.8

So my run off at 5.7-5.8 is ok. I guess all I can do is experiment

I'd pour off the runoff. It makes flushing even more unnecessary than it usually is.

bravedave said:

I'd pour off the runoff. It makes flushing even more unnecessary than it usually is.

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yup get rid of run off other wise the plant will be sucking back up all the crap that you washed out when you watered

I decided to go high with the ph. In order to get my runoff ph to 6.1 I had to water and feed with a ph of around 7.2. Still seeing some systems of brown spots and also parts of the mid and top leaves getting a lighter green/yellow look. I was running lights on for 24 hrs also, so I'm not sure if that was affecting it or not. 1 thing that I did right after I upped the ph was a gave both plants a foliar spray of compost tea. I started changing the leaves back to dark green and the brown spots stopped spreading. Actually I have to correct that, the foliar spray was with Epsom salt, not compost tea

you should look at the ph chart. it will show you what the ph has to be to take in certain nutrients. by foliar feeding, the plants are taking in the calmag but you still have a soil ph problem. imo

when in veg(soil)your plant requires more nitrogen and should be around 6-6.3 for maximum intake. when they go into flower they require more potassium and phosphate which require a bit higher ph for maximum intake of these nutrients.For every week in flower I add about .5 on my ph so by the time your done feeding your flowering plants, your at a ph of about 6.7. that's what I do and it works great. hope this helps