Nute burn or deficiency? Help please!

[Thetallstoner]

Hey guys, my white widow fem plants are about a month old now, and growing pretty strong. I accidentally overfed them a couple days ago and right when I saw the yellowing tips I flushed the whole system out and refed with about half strength like I have been previously. I am growing with just generic potting soil mixed with perlite, the soil isnt prenuted, feeding with miracle gro tomato food. After I flushed there are brown spots showing up on my plant that are slightly getting bigger as of today. I was wondering if it was a deficiency due to the large flush I just did or if it's still an effect of the overfeeding that I did? Also the ph is a Tad high at about 7.2.. Idk if that could be the problem or not? I've been trying to lower the ph with lime juice mixed in water but any suggestions would be appreciated as to an effective way to go about lowering soil ph! Thanks! Ps. I am growing with a 180w apollo horticulture led light that is about 12 inches from the plants.

 

[PeytonManning]

Looks like nute burn and cal/mag deficiency, could be lockout because of pH and overfeeding. Get pH under control and some cal/mag in there.

 

[Thetallstoner]

Looks like nute burn and cal/mag deficiency, could be lockout because of pH and overfeeding. Get pH under control and some cal/mag in there.

Thanks! How should I go about changing the ph fast? Most of the ph down products take a few months to lower the ph.

 

[PeytonManning]

Using pH down works fast. It should never take more than a couple days at most to change the pH. Lemon juice works great for it if you don't have pH down. You'll have to make sure and check your runoff pH and compare it to your pH going in to get an accurate reading to adjust to. Make sure your nutes are pH'd properly before adding to plants

 

[Thetallstoner]

Using pH down works fast. It should never take more than a couple days at most to change the pH. Lemon juice works great for it if you don't have pH down. You'll have to make sure and check your runoff pH and compare it to your pH going in to get an accurate reading to adjust to. Make sure your nutes are pH'd properly before adding to plants

Ok thanks, I've been trying to use lime juice, and I bring the ph of my water down to about 5.5-6 but the runoff is still coming out at about 7. Should I just use more lime juice and bring the ph of the water down more?

 

[Thetallstoner]

Using pH down works fast. It should never take more than a couple days at most to change the pH. Lemon juice works great for it if you don't have pH down. You'll have to make sure and check your runoff pH and compare it to your pH going in to get an accurate reading to adjust to. Make sure your nutes are pH'd properly before adding to plants

Ok thanks, I've been trying to use lime juice, and I bring the ph of my water down to about 5.5-6 but the runoff is still coming out at about 7. Should I just use more lime juice and bring the ph of the water down more?

 

[PeytonManning]

I'd probably have to get that answer from a soil grower. I grow in 100 percent perlite since day 1 and don't plan to change. In my signature is a link to peyton and Pals Perpetual Playground, that's a place to ask questions and they're are plenty of soil growers who could answer this much better

 

[Thetallstoner]

I'd probably have to get that answer from a soil grower. I grow in 100 percent perlite since day 1 and don't plan to change. In my signature is a link to peyton and Pals Perpetual Playground, that's a place to ask questions and they're are plenty of soil growers who could answer this much better

Ok thank you so much!! I'm on my way to get ph down as we speak

 

[OlderStoner]

Let me soil away at this one. There are two arguments about ph and soil. One says you should always apply the proper ph water to maintain a steady ph in the medium no mater what it is, but in this case we stick with soil. I come down on this side. There are others who will argue that it's a big waste of time and to just dump any clean water into the soil. I do not agree with this but the theory does have it's merits and followers. I don't think these folks have had a chance to see water coming right out of the taps at my house at +8 and even +9 ph. And some of the cleanest rain water you'd ever find falls where I live but I've checked it to find it very high, sometimes above 9.0. So why would you want to pour that into a pot you're trying to maintain around 6.5 ph?

Now as for what to use, the PH Down Concentrate I picked up at a local hydro shop works great for me. You can use lemon/lime juice but again there are arguments on both sides of this. If you use the store bought concentrates, be very careful with them as just one or two drops too many can ruin and entire gallon of water and send it below 4.0 ph in a heartbeat.

I just watered some of my plants today. I don't buy expensive R/O water or bottled water or use filters. I just fill up a Styrofoam cooler once a week and let it sit out for about 48-72 hours. Then I check and adjust the ph slowly over the next day or two until I maintain 6.5. Tap water sometimes has a buffer in it and it's not unusual to get the ph down only to see it rise again the next morning. So that's why I condition the water over several days including giving it some brisk stirrings 2-3 a day. Once everything is all set I just use it as water for the plants. I check the runoff, again some people have told me that I'm insane to do this with a soil grow, but I think it's important. I usually see the run off is within that magic 6.3 to 6.8 range. If it's there I leave it alone until the next watering and if it's high/low I make note of it to make a slight adjustment for the next watering.

 

[Thetallstoner]

Let me soil away at this one. There are two arguments about ph and soil. One says you should always apply the proper ph water to maintain a steady ph in the medium no mater what it is, but in this case we stick with soil. I come down on this side. There are others who will argue that it's a big waste of time and to just dump any clean water into the soil. I do not agree with this but the theory does have it's merits and followers. I don't think these folks have had a chance to see water coming right out of the taps at my house at +8 and even +9 ph. And some of the cleanest rain water you'd ever find falls where I live but I've checked it to find it very high, sometimes above 9.0. So why would you want to pour that into a pot you're trying to maintain around 6.5 ph?

Now as for what to use, the PH Down Concentrate I picked up at a local hydro shop works great for me. You can use lemon/lime juice but again there are arguments on both sides of this. If you use the store bought concentrates, be very careful with them as just one or two drops too many can ruin and entire gallon of water and send it below 4.0 ph in a heartbeat.

I just watered some of my plants today. I don't buy expensive R/O water or bottled water or use filters. I just fill up a Styrofoam cooler once a week and let it sit out for about 48-72 hours. Then I check and adjust the ph slowly over the next day or two until I maintain 6.5. Tap water sometimes has a buffer in it and it's not unusual to get the ph down only to see it rise again the next morning. So that's why I condition the water over several days including giving it some brisk stirrings 2-3 a day. Once everything is all set I just use it as water for the plants. I check the runoff, again some people have told me that I'm insane to do this with a soil grow, but I think it's important. I usually see the run off is within that magic 6.3 to 6.8 range. If it's there I leave it alone until the next watering and if it's high/low I make note of it to make a slight adjustment for the next watering.

Wow thank you! That helps me a lot. Personally I had some issues with not being able to get the lime juice mixture down to the right ph runoff. I would bring the water ph down to about 5 and water with it, but my soil runoff would still be at around 7.5! I just lowered it a little more and added a larger volume of water to see if I could bring it down to a desirable level. Do you think the problem for the plants is more nutrient related or ph related? Because my fertilizer contains magnesium and an acceptable npk ratio, and to me it almost looks like a phosphorus deficiency but I could very well be wrong. Thanks for the response!

 

[OlderStoner]

I just checked on some of my water sources tonight. The remaining water in the cooler which had already been prepared for the last week and was being used because it was perfect at 6.5 ph. The last gallon or so was used tonight for a plant I transplanted into a large pot. I decided to recheck the ph and even though yesterday it was a perfect 6.5, tonight it was up to 7.2. So I added a few drops of PH Down and stirred it well. I used all of it on the transplant and then refilled it with water straight from the taps. This last weekend water out of the taps was about 7.4, but tonight it's 8.2. TDS was 290, which I think is too high for water right out of the taps. Whatever the case, I continue to use this source for water, because it's cheap and right at hand. But I will also check the ph and adjust it down and let it sit open to evaporate as much of the chlorine as possible. So far the plants are responding nicely.

 

[MassMedMan]

I usually see the run off is within that magic 6.3 to 6.8 range. If it's there I leave it alone until the next watering and if it's high/low I make note of it to make a slight adjustment for the next watering.

Thank you for sharing this. I'm curious -- if my water/feed going in is 6.5, and say my run off is, say 7.0 -- can I lower the PH by using a water/feed the next time lower than 6.5? Say I got down to 6.0 -- would I see a change in my run off PH? Might be too many variables but I figured I'd ask.

 

[OlderStoner]

In my last grow I had the same problem. I mixed up a batch of some nice organic potting soil and some bagged topsoil that I bought at the local big box store. The topsoil seemed to be where I screwed up. That soil got so heavy with water and I could pour straight lemon juice into it and it would come out 7.5 and higher. Just joking but I do remember in a desperate attempt to get the ph of the runoff down I poured some 3.5 ph water in it...still got way over 7.5 in the runoff. It's a tricky thing I admit. This grow I've been real careful with the ph and at almost 6 weeks in this grow I'm seeing runoff from all of them in that 6.5 range. I should add here that lowering or raising the ph too quickly is not good for the plant. But you should see a lowering of the ph if you're using something around 6.0. Remember, you're shooting for that 6.3 to 6.8 range in veg, and maybe go just a little lower in flowering but not lower than 6.0. For soil grows this should keep you in the green.

Probably the trickiest thing of all is knowing, or at least trying to know when you have a deficiency and when you have a lock-out. The signs that show trouble with one or more nutes may not be from not enough but too much of that or something else. That's why, at least IMO, I take the time and care to ph the water I use. And it's real easy to overuse the nutes. Less is best.

BTW, I don't have a link with me right now, but there are many of them all over this forum that point to the nice graphical chart that shows what nutes are absorbed or blocked at various ph levels. You'll find that the nutes cannabis needs when grown in soil do best when the ph is right in that 6.3 to 6.8 range.

 

[MassMedMan]

Thank you!