EC, pH questions when growing in soil

[anolis]

Hi everyone,

My first plant is just flowering. I wanted to try out growing 1 cannabis plant in a simplified way, so I got an all in one feeding powder (Green House brand). Everything was going fine until very suddenly my plant started to display what I believe to be a calcium deficiency during second week of flowering. I bought a calcium supplement, an EC meter and pH drops. I did not get a pH meter as I am growing in soil and read that it is not that neccessary to have it. Now that I have all of that, I wanted to make sure that I got the basics right and ask you guys what you think of these measurments.

I measured pH of my tap water with the pH drops and it seems to be 8.5. I also measured it after adding all the nutrients and calcium powder and it read between 6-6.5. I guess that means pH for feeding the canabis is good? But is pH 8.5 okay on the days when I only water my plant and not feed it? If not, should I also buy and add pH down to get it to the 6-6.5?

I also measured the EC of the tap water which was 0.3. I read somewhere this indicates that my tap water is soft (does not contain alot of Calcium and Magnesium). I also measured EC of my feeding solution and it was 1.7 mS/cm . Is that okay?

In the feeding powder manual it says that you should flush the plant if the runoff is higher than 2.5. But I also got an advice on this forum that flushing is not great when growing in soil so it is better to "flush" only by having 50% runoff.

Did I get anything wrong and is there anything else that is crucial to know?

Thank you for your help!

 

[PeaceLove&Buds]

I’m in coco so I’ve no idea but I just wanted to say good luck

 

[anolis]

I’m in coco so I’ve no idea but I just wanted to say good luck

Thanks!

My first attempt was in coco and after the second seedling died I learned that the quality of coco is important as mine was unbuffered. I then just switched to soil because I read it can be more forgiving for a beginner.

 

[JP1]

That water and pH should be fine. Most likely not a calcium deficiency. Rare to have a cal deficiency in soil and that water is hard enough to supply all the calcium you need. Most likely too much of something causing the plants to stop absorbing the calcium. You never want to flush soil since it will throw everything out of balance and it'll take too long to fix with autos. Full size pictures always help. Personally, it's much easier to grow in coco then soil for me

 

[anolis]

That water and pH should be fine. Most likely not a calcium deficiency. Rare to have a cal deficiency in soil and that water is hard enough to supply all the calcium you need. Most likely too much of something causing the plants to stop absorbing the calcium. You never want to flush soil since it will throw everything out of balance and it'll take too long to fix with autos. Full size pictures always help. Personally, it's much easier to grow in coco then soil for me

This looks exactly like photos showing calcium deficiency online. It also only appeared on new leaves, which is one of the signs. But you might be right that it is not the lack of calcium that is causing this but a nutrient lockout. pH of water after I add the feeding powder seems fine, but maybe the soil got too acidic because I am watering with high acidity tap water on watering days?
The feeding powder I am using recommends adding calcium powder if your water is not hard though (page 13 on the PDF attached below), so maybe it was a problem that I wasn´t doing that until now (I believed my water was medium hard, as I read online, but now that I saw the EC reading was 0.3 it seems to be soft bordering on medium hard?).

https://shop.greenhousefeeding.com/downloads/GHF_M+B_2019_UK-AU.pdf

 

[Cannaficionado]

I agree with jp and I dont think its calcium deficiency. My guess is if you arent adjusting the ph of your inputs, you've achieved a lockout and that build up is causing your plant to stop uptaking nutrients, at a starting ph of 8.5 thats high. Your soil will buffer some of that down if the soil is in the proper range. The problem you face now is readjusting the ph of your soil which takes a significant amount of time once you start getting it way out of range.

Yes always buy ph adjusting solutions. I have both ph up and ph down, though I hardly use ph up unless I accidentally add too much ph down. You should also bite the bullet and get a dedicated ph pen like one from apera but the cheap ones will do just fine as long as you keep them calibrated and stored properly. I recommend the apera because the probe is replaceable and it's recommend to get a new meter every 2 years. When you add ph adjustment solutions, only add a few drops at a time and mix, wait 10 minutes then test. It needs time to react. If your ph was reading in the ok levels there's a chance that you didn't wait long enough after mixing your nutrients to test and it was too low or still too high, which can also cause lockouts. The starting ph of my water is between 7.5 and 8.0 and with a full mix of nutrients I still usually need to add a few drops of ph down.

When you water in soil whether it's plain or with food the ph should go no higher than 6.5. I said before that your soil will buffer the ph of your inputs but thats only if its already in the correct range. So if your soils ph is 6.5 and you water at like 6.8ph every once and a while the ph will get brought down slightly as it runs through the medium and exchanges ions. But if you continously water with too high of a ph it will slowly raise the ph of the root zone and cause nutrient lock outs. Most nutrients in soil are absorbed between 5.8-6.5. That puts you in the range where everything is pretty easily taken up. Always water to 10-15% runoff too, this will help prevent salt build up.

If I were you I wouldn't focus too much on ec in soil for the most part focus on ph and total ppm. Veg your inputs should be between 6.0-6.5ph and feeds shouldn't go much higher than 600ppm and 5.8-6.3ph in flower and you can feed up to 1000ppm if everything is dialed in right but 800ppms is plenty.

Edit: sorry I'm so used to photos, autos ppms are usually lower about 150-200 ppm lower in each stage.

I hope this helps.

 

[Cannaficionado]

I agree with jp and I dont think its calcium deficiency. My guess is if you arent adjusting the ph of your inputs, you've achieved a lockout and that build up is causing your plant to stop uptaking nutrients, at a starting ph of 8.5 thats high. Your soil will buffer some of that down if the soil is in the proper range. The problem you face now is readjusting the ph of your soil which takes a significant amount of time once you start getting it way out of range.

Yes always buy ph adjusting solutions. I have both ph up and ph down, though I hardly use ph up unless I accidentally add too much ph down. You should also bite the bullet and get a dedicated ph pen like one from apera but the cheap ones will do just fine as long as you keep them calibrated and stored properly. I recommend the apera because the probe is replaceable and it's recommend to get a new meter every 2 years. When you add ph adjustment solutions, only add a few drops at a time and mix, wait 10 minutes then test. It needs time to react. If your ph was reading in the ok levels there's a chance that you didn't wait long enough after mixing your nutrients to test and it was too low or still too high, which can also cause lockouts. The starting ph of my water is between 7.5 and 8.0 and with a full mix of nutrients I still usually need to add a few drops of ph down.

When you water in soil whether it's plain or with food the ph should go no higher than 6.5. I said before that your soil will buffer the ph of your inputs but thats only if its already in the correct range. So if your soils ph is 6.5 and you water at like 6.8ph every once and a while the ph will get brought down slightly as it runs through the medium and exchanges ions. But if you continously water with too high of a ph it will slowly raise the ph of the root zone and cause nutrient lock outs. Most nutrients in soil are absorbed between 5.8-6.5. That puts you in the range where everything is pretty easily taken up. Always water to 10-15% runoff too, this will help prevent salt build up.

If I were you I wouldn't focus too much on ec in soil for the most part focus on ph and total ppm. Veg your inputs should be between 6.0-6.5ph and feeds shouldn't go much higher than 600ppm and 5.8-6.3ph in flower and you can feed up to 1000ppm if everything is dialed in right but 800ppms is plenty.

Edit: sorry I'm so used to photos, autos ppms are usually lower about 150-200 ppm lower in each stage.

I hope this helps.

I should have remembered this from the beginning but adding benificial microbes like myco will help keep your root zone in a better overall balance so if your food doesn't have added microbes it's never a bad thing to add something like recharge or a similar product. Those microbes can help store extra nutrients inside themselves and are released as the plant calls for them. Both organic molecules and salt based. They will act as a buffer for your food, and help regulate the food uptake. You dont essentially need them if you got a good grasp on nutrient balance and uptake but they do help tremendously if you dont. Plus some help in trichome production too, not directly but they help create sugars that the plant uses to make cannabinoids.

 

[anolis]

I agree with jp and I dont think its calcium deficiency. My guess is if you arent adjusting the ph of your inputs, you've achieved a lockout and that build up is causing your plant to stop uptaking nutrients, at a starting ph of 8.5 thats high. Your soil will buffer some of that down if the soil is in the proper range. The problem you face now is readjusting the ph of your soil which takes a significant amount of time once you start getting it way out of range.

Yes always buy ph adjusting solutions. I have both ph up and ph down, though I hardly use ph up unless I accidentally add too much ph down. You should also bite the bullet and get a dedicated ph pen like one from apera but the cheap ones will do just fine as long as you keep them calibrated and stored properly. I recommend the apera because the probe is replaceable and it's recommend to get a new meter every 2 years. When you add ph adjustment solutions, only add a few drops at a time and mix, wait 10 minutes then test. It needs time to react. If your ph was reading in the ok levels there's a chance that you didn't wait long enough after mixing your nutrients to test and it was too low or still too high, which can also cause lockouts. The starting ph of my water is between 7.5 and 8.0 and with a full mix of nutrients I still usually need to add a few drops of ph down.

When you water in soil whether it's plain or with food the ph should go no higher than 6.5. I said before that your soil will buffer the ph of your inputs but thats only if its already in the correct range. So if your soils ph is 6.5 and you water at like 6.8ph every once and a while the ph will get brought down slightly as it runs through the medium and exchanges ions. But if you continously water with too high of a ph it will slowly raise the ph of the root zone and cause nutrient lock outs. Most nutrients in soil are absorbed between 5.8-6.5. That puts you in the range where everything is pretty easily taken up. Always water to 10-15% runoff too, this will help prevent salt build up.

If I were you I wouldn't focus too much on ec in soil for the most part focus on ph and total ppm. Veg your inputs should be between 6.0-6.5ph and feeds shouldn't go much higher than 600ppm and 5.8-6.3ph in flower and you can feed up to 1000ppm if everything is dialed in right but 800ppms is plenty.

Edit: sorry I'm so used to photos, autos ppms are usually lower about 150-200 ppm lower in each stage.

I hope this helps.

You don´t think it is a calcium deficiency or you think it just wasn´t caused by too litlle calcium, but rather the plant not being able to aborb it? Because the symptoms look the same to me, so I am wondering which nutrient you think it is lacking?

This was very helpful, thanks. I just didn´t get what you meant whith not focusing on EC in soil, but rather total ppm. I am measuring EC of water and ppm is just a different conversion, no?

Just to make sure I get it. On watering days, I use my tap water, add calcium to reach the desired EC or ppm (0,4 EC or 200 ppm in flowering week two for example), measure pH and bring it down to 5.8-6.3 pH, right?

I also just saw there exist advanced nutrients, which adjust the pH of your soil without the need to measure it. Do you know about it? If this works I would prefer to buy this than getting the pH pen and pH up down solutions.

Thanks again!

 

[Cannaficionado]

You're right but you'll get a better idea if you get a tds meter. Ec does tell you how much salts are dissolved in water yes, ive never been successful that way. Since I started measuring ppm and ph it seems like I have a lot less problems in soil.

In my experience ec is used by people that use ro water or something close where there is absolutely nothing in the water to begin with, but you already have dissolved solids in your water so your ec isn't a great representation of what's in your water. Im not going to be able to tell you what's lacking if anything, I think your rootzone is out of balance and unable to take up certain things. You said your water is relatively soft which means it's got salts in it, so if you only go by electric conductivity, it does take into account for what's in there but you don't know WHAT that is. Tap water has a lot of stuff in it.

Heres a chart that shows all the interactions of nutrients and how the balance of each effects others. And remember ph effects this too. Too high and too low some of these nutrients will not be taken up at all.

As far as soil ph, get equal parts distilled water and a sample of soil, mix them together in a clean glass or jar, wait for the soil to settle on the bottom and ph the water left on top, that will give you an idea of what your soil ph is at. It's called a slurry test. But you want the sample to be as close to the root zone as possible. If I do it I go like 2 inches down at the edge of the pot. Also I hardly ever add calcium to my grows. I use spring water from a natural spring close to me. It's ppms are usually 90-150 so I already dial back my nutrients by a bit. I know from the water report theres already plenty of calcium and magnesium in my water so its readily available every time I water even with no food, but at the start of flower I will add a quarter dose as the nutrient balance shifts a little bit. You can see in the chart as the plant wants more phosphorus and potassium it effects pretty much everything else.

 

[shumway]

I also just saw there exist advanced nutrients, which adjust the pH of your soil without the need to measure it. Do you know about it? If this works I would prefer to buy this than getting the pH pen and pH up down solutions.

It only adjusts the ph of the feed going in and not the soil itself, Any idea of your soils actual ph level?