EC, pH questions when growing in soil

[anolis]

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.View attachment 1737860

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.

Thanks! Just wondering, could I do the slurry test with pH drops because that is all I got.

 

[anolis]

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.

Is this useful when growing organic or also synthetic? Although I am considering switching to organic for the next grow anyway.

 

[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.

Thanks! super useful advice.

 

[Cannaficionado]

Is this useful when growing organic or also synthetic? Although I am considering switching to organic for the next grow anyway.

Organic is sometimes easier as long as you ammend the soil correctly, and top dress, but there are drawbacks. 100% organic growing relies on microbes to break down organic components and convert them into available nutrients the plant can use, which takes time, so if an imbalance occurs it's takes longer to show up and longer to get rid of. I use benificial microbes and my nutrients are a blend of organic and synthetics. I use microbes because they can act as a buffer only supplying nutrients as the plant calls for them, but that doesnt mean that they completely regulate nutrient uptake. They just help a bit and are needed since some of my nutrients need them to work. If you use anything use some form of mycorrhizae. Especially early on. Myco will actually help roots tremendously, they form a barrier around root tissue forcing harmful bacteria out as well as regulate nutrient uptake. Which is mostly whats in my version of recharge (fox farm microbe brew)

Another useful bit of info is synthetic fertilizers are just synthetic produced elemental forms of organic compounds so when the microbes in organics break down the organic materials the byproduct is technically the exact same thing synthetic fertilizer companies make. The only difference being the plant sends signals to the rhrizosphere saying it needs this nutrient and it's given as the plant needs it. Synthetic is immediately available so as soon as that solution touches the root it can be absorbed.

 

[Cannaficionado]

Thanks! Just wondering, could I do the slurry test with pH drops because that is all I got.

Yeah I assume that you could. Just make sure you give the soil time to settle after mixing.