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