Newer leaves yellowing, nutrient issues?

[Creeperpark]

In some areas, tap water is a big problem and will cause big problems with cannabis. The tap water in my area will kill a plant when used and is impossible to grow a plant all the way into flowering. If you get a Reverse Osmosis water filter set up for about $100 you will be glad you did. I have seen growers stop having problems just by switching to RO water. The plants respond to RO very well and is what the pros use. You got to change your water friend. Good luck

 

[Douglas.Curtis]

20 years with r/o, and it is painful to read the nightmare other growers go through trying to get workable help using their tap water.

Get r/o, and get access to a large mass of directly useable information by eliminating tons of guesswork.

 

[TanzanianMagic]

By the way, I watered with 9,5L and:
- 2ml/L BioGrow
- 1.5ml/L BioBloom
- 1ml/L TopMax
- 0.1ml/L Calmag
- PH: 6.6
- EC: 1.5

Should I increase?
One note: the last watering I said it was 1.3EC and that wasn't correct. Maybe around 2 to 2.5 is much more realistic since 1.3 was the reading (forgive me) before adding nutes.

Runoff (not after 30 minutes, but after 10), with cleaned tray after after pouring 0.07EC water (not PH):
- PH: 6.7
- EC: 4.8

You may be overfeeding/underwatering.

The maximum EC should be 2.1, and that is well into advanced flowering.

The way to think of feeding cannabis is this:

Veg: prefertilized soil (Bio Canna Terra for instance, or supersoil) and very light supplementary feeding of 0.1 upto 0.3 EC in growth nutrients. Low nutrients and low watering helps the root system expand.

Flower: start increasing the EC by 0.2 EC per week (100 PPM on the 50 scale). First with growth nutrients, a combination of growth and flower, and then just flower plus flowing stimulators. Also start raising the pH.

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Just a few random thoughts.

A slow but steady increase in pH and EC is what the plant expects from it's environment.

It also gives the roots a chance to 1) expand during vegging and 2) toughen up over time to take higher concentrations of nutrients during flower without getting burned.

I think that if you want to know what a plant needs, you look at the environment/location it has evolved in. The birthplace of cannabis is given as the Tibetan Plateau. Qinghai Lake and the Buha River are good examples. The pH and EC of the water are very high.

The results showed that the pH of river water in Buha River Basin ranged between 7.91 and 9.21, with an average of 8.43. ... The ionic abundance of river water in Buha River Basin followed the sequence of Ca²⁺> Na⁺> Mg²⁺> K⁺> NH4⁺ for cations, and SO4²⁻>Cl⁻>NO3⁻ for anions.

Cannabis, being a plant of the old floodplains of the Alluvial Zone (the area from the water table of a river to the high water mark is the floodplane; the Alluvial Zone is the current flooplane plus all the old flood planes; because cannabis seeds can't handle flooding/immersion for more than 24 hours, cannabis is a plant of the old floodplains; the old floodplains get a high water table when the river overflows, they don't get flooded; in my experience cannabis likes a water table from 0.5 feet to 2 feet - veg to flower; the need for increased watering/EC starts at early flowering; I'm starting to think that nitrogen deficiency in early-mid flower may be a sign of underwatering rather than actual nitrogen deficiency or nitrogen lockout for reasons other than underwatering).

 

[coo_kie]

That's your whole problem Hard 'tap" water. Thanks for info a little late. Know wonder your plants are turning yellow with added nutrients. You can spray iron on your plants all you want and waste your money but its not going to fix the problem. Everything goes j-waky towards the end when you use hard tap water. The pH will always swing super high after you water when using hard tap water. It can be hours later but that's why your plants are turning yellow. Because the accumulated hydroxy from all the past waterings has made the soil alkaline locking out iron. As long as you use that water it will still do what its doing. Acid only works temporarily for a little while and then swings back up because of the high accumulation.

I totally agree with you. That's the reason why I want to wash out all salts, because I'm thinking of this buildup that will cause trouble by blocking nutes and tricking me into thinking that's a deficiency from lack of nutrients rather than a lockout caused by salts.
I hope that spraying a solution enriched with iron on the leaves may help them a little bit, at least temporarily until the EC goes down where it was.
I've never had this consideration about PH changing even hours after waterings, I'll do some experiments later on. However readings should still give you some warnings, right? I mean, if PH is raising after watering with my tap water, does it keep that level or go down again? Because if it goes down, making me unaware, that is a problem I can't overlook.

For waterings I've always mixed this tap water with rainwater. Could this be a problem even if tap water was in smaller amounts? I made the mix in such a way that EC was about 2.0 (out of 10L, let's say about 8L rainwater and 2L tap water).

In some areas, tap water is a big problem and will cause big problems with cannabis. The tap water in my area will kill a plant when used and is impossible to grow a plant all the way into flowering. If you get a Reverse Osmosis water filter set up for about $100 you will be glad you did. I have seen growers stop having problems just by switching to RO water. The plants respond to RO very well and is what the pros use. You got to change your water friend. Good luck

A friend of mine got RO water, I can think about using that, but rainwater will work aswell I guess.

You may be overfeeding/underwatering.

The maximum EC should be 2.1, and that is well into advanced flowering.

The way to think of feeding cannabis is this:

Veg: prefertilized soil (Bio Canna Terra for instance, or supersoil) and very light supplementary feeding of 0.1 upto 0.3 EC in growth nutrients. Low nutrients and low watering helps the root system expand.

Flower: start increasing the EC by 0.2 EC per week (100 PPM on the 50 scale). First with growth nutrients, a combination of growth and flower, and then just flower plus flowing stimulators. Also start raising the pH.

----------------------------------------------------------------------------------------------------------

Just a few random thoughts.

A slow but steady increase in pH and EC is what the plant expects from it's environment.

It also gives the roots a chance to 1) expand during vegging and 2) toughen up over time to take higher concentrations of nutrients during flower without getting burned.

I think that if you want to know what a plant needs, you look at the environment/location it has evolved in. The birthplace of cannabis is given as the Tibetan Plateau. Qinghai Lake and the Buha River are good examples. The pH and EC of the water are very high.



Cannabis, being a plant of the old floodplains of the Alluvial Zone (the area from the water table of a river to the high water mark is the floodplane; the Alluvial Zone is the current flooplane plus all the old flood planes; because cannabis seeds can't handle flooding/immersion for more than 24 hours, cannabis is a plant of the old floodplains; the old floodplains get a high water table when the river overflows, they don't get flooded; in my experience cannabis likes a water table from 0.5 feet to 2 feet - veg to flower; the need for increased watering/EC starts at early flowering; I'm starting to think that nitrogen deficiency in early-mid flower may be a sign of underwatering rather than actual nitrogen deficiency or nitrogen lockout for reasons other than underwatering).

So much knowledge in this place, I'm glad to see that . I'm not thinking of underwatering, mainly because I'm careful to water them as soon as the pot is dry enough (not bone dry, of course), but it happens sometimes that I wait a little bit longer because I'm busy elsewhere. In addition, soil seems to dry in the correct amount of time (2-3 days). However, since I turned on the dehumidifier at the beginning of flowering, it dries faster sometimes.
Overall, I love your considerations about the environment.

By the way, next watering I'm gonna lower PH to 6 and see what happens.
I'm sure enough things would have been more simple with quality water.

 

[St. Phatty]

What are the nutes used by the people who post the pics of beautiful finished buds - with almost no yellowing ?

 

[Three Berries]

As the soil dries out the pH drops. It's simple chemistry. The same will happen if you take a cup of nutes, leave it out and test it as the water evaporates. The minerals that make the acids don't evaporate and only concentrate. So a constant moisture level would help maintain a constant pH.

Might have to look into those BluMats again.....

 

[coo_kie]

Update: This morning I sprayed them with 1gr of chelated iron powder in 1L of water as the instructions said. I actually used very little of this solution (maybe 70-90ml). There's some of it that dried on the leaves so there are some brownish spots that I will wash in the next days with clean water. I don't know if this is supposed to happen cause I haven't got time to go into deeper research and it's my first time foliar feeding.
Now, to prevent that brownish spots I guess I should create a less concentrate solution.
I also did some flushing: just plain water at 0.07EC.
Now, you guys are right and I experienced different readings that I took while I was emptying trays for runoff. At first values were lower, then they went higher. It's clearly showing a trend where plants with more leaves turning yellow have also a higher runoff EC (about 4.2 - 4.5), while the greenish ones have lower values (3.1-3.3).
After a few cycles of washing, values dropped a bit but still not in the safe range. As @Creeperpark said they'll work out on their own after a few waterings.

This morning:

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This evening:

 

[Cerathule]

BioBizz ActiVera contains alot of micros and is borderline high in Fe - if you think you may want to supp micros e.g. next run. About 1ml/l fully satisfies Cannabis max Fe demand in high flower.

BB fertilizer contains a high amount of acidifying ammonia. When plants take this up, the roots will exchange it and that's gonna drag the substrate pH down. I suspect your hard water works against that.

Your well-water - I'd say, don't use it for now. Wellwater sometimes contains high amounts of iron-3, other toxic micros/metals or much too much CaCO3. You have rainwater - together with Calmag that will be a very good water. Usually you're aiming for about 120ppm Ca & 60ppm Mg at that stage of the grow, though temps, light, feedstrength, medium can modulate that.

But it's not clear how much Ca is still prevalent in the soil's solution and CEC.
Usually about EC 0,2 - 0,4mS, with largely Ca, Mg & S contributing to this, but not so much Na, Cl - will be suitable plantwater before fertilizer.

The BB Calmag contains 35ppm Ca & 12ppm Mg per ml.

 

[RobFromTX]

In some areas, tap water is a big problem and will cause big problems with cannabis. The tap water in my area will kill a plant when used and is impossible to grow a plant all the way into flowering. If you get a Reverse Osmosis water filter set up for about $100 you will be glad you did. I have seen growers stop having problems just by switching to RO water. The plants respond to RO very well and is what the pros use. You got to change your water friend. Good luck

I have a friend in Montana. The water there is so high in calcium the it will cause nutrient lock out after only 2 or 3 waterings. Is that your issue or is it high chlorine? I get my grow water from a guy i know on a well. So far so good

 

[Creeperpark]

I have a friend in Montana. The water there is so high in calcium the it will cause nutrient lock out after only 2 or 3 waterings. Is that your issue or is it high chlorine? I get my grow water from a guy i know on a well. So far so good

Both excess calcium and chemicals have been a problem with my tap water.

 

[RobFromTX]

Both excess calcium and chemicals have been a problem with my tap water.

I was reading somewhere that letting the tap sit out for a few days will take care of the chlorine but calciums a whole different ball game for sure

 

[Three Berries]

Potassium hydroxide will immediately strip the calcium out of the water and settles out as CaO. But then you have quite the high pH water.....

So what would be the proper Ca feeding per watering at ppm? What is too much assuming no CalMag type additions? I realize it is per plant needs.

 

[RobFromTX]

Potassium hydroxide will immediately strip the calcium out of the water and settles out as CaO. But then you have quite the high pH water.....

So what would be the proper Ca feeding per watering at ppm? What is too much assuming no CalMag type additions? I realize it is per plant needs.

Landrace sativas are very sensitive to high Ph. I can definitely vouch for that

 

[Creeperpark]

I was reading somewhere that letting the tap sit out for a few days will take care of the chlorine but calciums a whole different ball game for sure

In the old days, you could let the water set and the common chlorine would evaporate. Today it's different they use new chemicals that are designed to stay until the end. The only way to clean tap water is RO or distillation. Big cities use chloramine with chlorine to keep the water from turning green.

Chloramines are a group of chemical compounds that contain chlorine and ammonia. The particular type of chloramine used in drinking water disinfection is called monochloramine which is mixed into water at levels that kill germs but are still safe to drink.google.

 

[RobFromTX]

In the old days, you could let the water set and the common chlorine would evaporate. Today it's different they use new chemicals that are designed to stay until the end. The only way to clean tap water is RO or distillation. Big cities use chloramine with chlorine to keep the water from turning green.

Chloramines are a group of chemical compounds that contain chlorine and ammonia. The particular type of chloramine used in drinking water disinfection is called monochloramine which is mixed into water at levels that kill germs but are still safe to drink.google.

Wow it makes you wonder what it does to your body

 

[Douglas.Curtis]

You can add humic acids to water with chloramine and chlorine to get rid of it. Keep adding drops and stirring until a faint tint stays in the water.

 

[Three Berries]

Wow it makes you wonder what it does to your body

Much like fluoride.

 

[Three Berries]

Activated charcoal filters will remove chloramine.

Using a granular activated carbon (GAC) filtration system is the most effective way to remove chloramines from water and make a great tasting beer. GAC filtering not only removes chloramines and chlorine, but it also reduces the levels of other harmful contaminants like industrial chemicals, pesticides, trihalomethanes, as well as other halogenated organic compounds. It is also effective in removing bad odors and tastes.

How to Remove Chloramines From Water When Brewing

Across the United States, water suppliers are more frequently adding chloramines to the water before sending it to the consumer. Find out why, what they do, and how you can get rid of them before brewing your beer.

www.commercialfiltrationsupply.com

 

[Cerathule]

You can add humic acids to water

yes, lots of acids seema to work to accomplish this goal, for example Ascorbic, too

 

[Douglas.Curtis]

Humic is easiest (not the most inexpensive. lol) since you have an immediate visual indicator everything has been torn apart and is now clean.