Correcting deficiencies and lockouts when using bottled nutes in soil

[ClassicT]

My plants have been teaching me a lot lately! Mostly, that nutrients work in specific tandem with one another and therefore straying too far outside of a particular manufacturer’s nutrient line and feeding schedule has a big potential to cause nutrient lockouts and deficiencies.

In my case, my ladies are in week 5 of flower, and have a major excess of phosphorous and a major deficiency of nitrogen. I found this from doing one of those RapiTest chem tests with the little vials and powders. I definitely overdid it on the bloom nutes and boosters a few weeks ago.

Of course, each plant is performing slightly differently. 2 of the 9 have very light lime green leaves on the top of the canopy (a result of bleaching caused by excess calcium I believe) and the other seven look pretty healthy. They ALL have purplish/red petioles, and they all have very very very very minor tip burn/yellowing. All have good and consistent bud growth, even the lime colored ones, which is a relief.

But even the healthy looking ones showed barely any detectable nitrogen in my soil test.

I watered with plain water last time, and got a nice pH 6.5 for my runoff.

Now I’m trying to determine what to include in my next water. N deficiency is confirmed, P excess is confirmed, and I suspect the purple petioles throughout indicate Mg deficiency. (K tested as “medium” amount.)

So I was planning to add a regular (regular meaning the low end of what the bottle label says to add at this stage) amount of a (0.5 - 0 - 0) to the ones that are the palest lime green, half that amount of the (0.5 - 0 - 0) to the ones that look slightly lime green, and the low end of the recommended amount of a (2 - 1 - 1) to the healthy looking ones.

Plus a teaspoon/gal of Epsom for all of them for the suspected Mg deficiency.

Does anyone have experience with correcting deficiencies and lockouts with bottled nutrients? Is is best to give the plant what it is lacking or is it better to get back on track with plain water for two weeks and then get back on track with a full feed of everything in your particular nute line?

It makes sense to me to add what they are lacking, and avoid adding what they have in excess, but my “thinking” was what got me in this mess to begin with.

I’d love some feedback on your tales of recovering from deficiencies and lockouts, specifically in soil with bottled nutes. Thanks all!

 

[Coloradoclear]

When I hear "excess" I think flush. When I hear nutrient burn I think flush. Sounds like some nice clean water might do your plants some good. I grow in ocean forest with advanced Sensi boom. The plants are fed once a week with nutrients. Currently at 3rd week of flowering, 1000 ppm, bloom, B-52, Big Bud. 10 ml A & B, 7 ml of B-52 & big bud.

 

[ClassicT]

Thanks for jumpin in. So I did give em plain water last time, and this time was considering giving them a low amount of what I know they are deficient in, N and Mg.

 

[ClassicT]

My soil is just pro-mix with worm castings. FFOF has a lot more nutes in the soil already than what I’m using.

 

[Xs121]

My plants have been teaching me a lot lately! Mostly, that nutrients work in specific tandem with one another and therefore straying too far outside of a particular manufacturer’s nutrient line and feeding schedule has a big potential to cause nutrient lockouts and deficiencies.

In my case, my ladies are in week 5 of flower, and have a major excess of phosphorous and a major deficiency of nitrogen. I found this from doing one of those RapiTest chem tests with the little vials and powders. I definitely overdid it on the bloom nutes and boosters a few weeks ago.

Of course, each plant is performing slightly differently. 2 of the 9 have very light lime green leaves on the top of the canopy (a result of bleaching caused by excess calcium I believe) and the other seven look pretty healthy. They ALL have purplish/red petioles, and they all have very very very very minor tip burn/yellowing. All have good and consistent bud growth, even the lime colored ones, which is a relief.

But even the healthy looking ones showed barely any detectable nitrogen in my soil test.

I watered with plain water last time, and got a nice pH 6.5 for my runoff.

Now I’m trying to determine what to include in my next water. N deficiency is confirmed, P excess is confirmed, and I suspect the purple petioles throughout indicate Mg deficiency. (K tested as “medium” amount.)

So I was planning to add a regular (regular meaning the low end of what the bottle label says to add at this stage) amount of a (0.5 - 0 - 0) to the ones that are the palest lime green, half that amount of the (0.5 - 0 - 0) to the ones that look slightly lime green, and the low end of the recommended amount of a (2 - 1 - 1) to the healthy looking ones.

Plus a teaspoon/gal of Epsom for all of them for the suspected Mg deficiency.

Does anyone have experience with correcting deficiencies and lockouts with bottled nutrients? Is is best to give the plant what it is lacking or is it better to get back on track with plain water for two weeks and then get back on track with a full feed of everything in your particular nute line?

It makes sense to me to add what they are lacking, and avoid adding what they have in excess, but my “thinking” was what got me in this mess to begin with.

I’d love some feedback on your tales of recovering from deficiencies and lockouts, specifically in soil with bottled nutes. Thanks all!

If it's my plants i'll definitely balance my nutes. I'll increase the deficiency slightly and reduce my excess inline with my other nute.

Plus a teaspoon/gal of Epsom for all of them for the suspected Mg deficiency.

A tsp I think is overdoing it. A tsp of epsom salt will give you 125 ppm of magnesium and 165 ppm of sulfur. Combine that with magnesium and sulfur of your other nute. I use less than a quarter of tsp of Epsom salt.

 

[ClassicT]

@Xs121 right on that makes sense. Thanks.

I based the 1 tsp/gal on a little internet research. I thought I chose the low end of what was recommended but I’ll consider reducing based on your advice.

One thing I’ve learned for sure lately, better too little than too much! It’s like getting burned on the stove as a kid. Everyone tells you, but you’ve got to feel the pain to learn the lesson!

 

[OldMedUser]

Maybe just foliar feed the plants what you think is lacking so you don't need to mess with the soil to see if it helps.

I grow a lot in ProMix with AN nutes. I'll mix ProMix HP with the ProMix Veg and Herb sometimes to give them some organic nutes for vegging and go light on the hydro feed until time to flip then give them a half dose, 2ml/L, of each of the 3 parts and a half dose of Big Bud about a week before the flip and just the other half the Big Bud for the next watering. Then play it by ear for the next few waterings until they get done the stretch then go with Lucas formula feeding for the rest of the flowering period.

Most PK boosters are way too high on P, which is great for tomatoes, but the BB has less than half the P as K which is best for pot. It's 0-15-40 with 10%S, aminos, citric and ascorbic acids. I've used it since it was invented and nothing else I've tried when I didn't have any has been a disappointment.

A tsp per gal of Epsom Salts will be fine. For a deficiency a Tbsp/gal is what is the usual dose. You figure you are too high in Ca so that would block Mg and where a foliar feed would help to correct the perceived deficiency without interference by the Ca in the soil.

 

[ClassicT]

@OldMedUser yes, I’m sure I have a Ca excess. I was using earth juice’s oily cann (their version of cal mag) and then I introduced a bloom booster that had 3% Ca and 1% Mg, basically doubling down my dose of these micros. D’oh! I read somewhere that Ca toxicity can cause photosensitivity, therefore the bleaching/lime green upper foliage. Ca toxicity in cannabis is so rare, it’s hard to find a lot of information on it, but reading other crop reports and aggie school docs led me there.

I like your suggestion on the foliar feed, makes sense to not further throw things out of balance in the soil, but in week 5 of flower? (I don’t wanna!)

(I like your signature... reminds me of that Richard Thompson song “Good things happen to bad people”. Great tune.)

 

[OldMedUser]

I like your suggestion on the foliar feed, makes sense to not further throw things out of balance in the soil, but in week 5 of flower? (I don’t wanna!)

I didn't take into account your stage of flowering. I don't hardly ever spray plants and never later in flower. Epsom salts in your water is probably your best bet then. They should get some Mg that way and the extra sulfur will be good for resin production and it's really hard to OD them on S.

(I like your signature... reminds me of that Richard Thompson song “Good things happen to bad people”. Great tune.)

Don't think I've ever heard the song and saw that sig on a quotes page somewhere and it stuck. (Explains a lot of my life.)

 

[polishpollack]

Bottle feeding plants is the easiest way to ruin a grow. Using a soil that is already ferted and left alone tends to be best for many people.

 

[ClassicT]

Bottle feeding plants is the easiest way to ruin a grow. Using a soil that is already ferted and left alone tends to be best for many people.

I have definitely learned that one the hard way during this, my first, grow. I would advise anyone who isn’t very adept in botany, horticulture and organic chemistry to stick to one manufacturer’s nute line, and pretty much follow it exactly.

In my grow, these bad interactions and lockouts only started occurring midway through flower. So I have good bud development despite. But I wonder what they could have been if I didn’t run into this trouble. I’m certain I sacrificed yield. I’m still pretty happy considering it’s my first grow. We’ll see how they turn out in the end. They fucking stink, so that’s good! Ha!

 

[ClassicT]

Found this article, good info on this topic:

Interactions between nutrients
Most growers know the importance of applying the right amount of macro- and micro-nutrients, and there are several ways of knowing whether a plant is lacking any of these elements. However, some of these deficiencies – or excesses on occasion – are not caused by a shortage of the element in question but rather by a poor combination with other nutrients, either in the potting mix, in the plant or both. In this article, we are going to look at the importance of the interaction between different nutrients and how it can affect the final crop.
By Inaki Garcia, CANNA Research

In 1953, D. Mulder published his “Les elements mineurs en culture fruitière”, one of the first studies of how different nutrients interact. The study included a graph, which is now commonly used. Over the years, other researchers have added other possible synergies and antagonisms. Clearly, studying the interactions between nutrients is essential for improving crop yield.

The Mulder’s Chart shows how elements interact. The dotted lines show which elements enhance each other. The solid lines show which elements antagonize each other. For example, calcium can cause a magnesium deficiency, while nitrogen can solve this deficiency. So adding extra magnesium isn’t necessary!

The relative proportions of different nutrients has a direct effect not only on plant nutrition, but also on the substratum in which the plant grows. Cations (positively charged elements) are to a greater or lesser extent retained by the negative charges in certain soil components, such as clay and organic matter. Cations include Na+, K+, Ca2+, Mg2+, NH4+ and H+ (sodium, potassium, calcium, magnesium, ammonium and hydrogen).

Plants absorb elements that are dissolved in water, which means that elements trapped in the soil cannot be used directly. In some cases, however, these elements can filter into the water in the substratum and thus be assimilated by the plant.

The more cations that the soil or substratum can hold, the greater its ‘Cation Exchange Capacity’ (or CEC). The proportion of cations in the soil directly influences the texture of the soil or substratum.

Here are some of the most important interactions between nutrients.

Nitrogen

When in the form of ammonium, NH4+, nitrogen interacts negatively with the plant’s uptake of calcium, magnesium and potassium, particularly when the NO3- (nitrate)/NH4+ (ammonium) ratio is low.

As a result, excess NH4+ can lead to a deficiency in any of these three elements. This is an important problem in hydroponic growing, which normally uses an inert growing medium with a low or zero CEC index; here the quantity of available calcium, magnesium and potassium depends solely on what is in the nutrient solution, unlike soils or substrata with high CECs which normally hold a large quantity of these elements.

There is also an antagonistic interaction between the anions Cl- and NO3- . Excess Cl- (very common in saline and/or sodic water) can reduce the plant’s absorption of NO3- .

The N/K ratio is also crucial when plants are passing from the growth (vegetative) phase to the generative (flowering or fruit-bearing) phase. The primary stimulus for a short-day or long-day plant to go from vegetative to generative is the number of consecutive hours of darkness. However, other stimuli, such as the N/K ratio, also affect these phenological states to some extent.

Fruit contains an abundance of potassium, and it is therefore essential to ensure a proper supply of potassium during generative periods. Yet regardless of how much potassium there is, if the ratio to nitrogen is too low, this can lead to a reduction in flower formation and plants with many vegetative parts (leaves and branches) and few generative parts (flowers and fruit).

Potassium

It is essential to get the proportion of potassium right, since it interacts both in the soil and in the plant with phosphorus, sodium, calcium and magnesium.

In clay soils with a high CEC, when the plants are irrigated with fertilizer solutions in which the potassium is dissolved in its ionic form, some of the potassium is adsorbed by the mineral and humic parts of the soil.

If you irrigate with a low-potassium solution, the potassium held in the soil is released for uptake by the plant. This exchangeable potassium and the solution are known as available potassium. As its name suggests, it is this kind that the plant absorbs most readily.

However, the potassium also comes in non-exchangeable forms which are strongly fixed to the soil components. In this case, it is not directly available to the plant and only enters into the solution when levels of exchangeable potassium are very low. The problem of using this potassium is that it takes a long time to go from its fixed state to the interchangeable state, which means that it is not readily absorbed by the plant.

Applying too much calcium and magnesium can cause a potassium deficiency; the K/Ca and K/Mg ratio should always be kept above 2 (but below 10, since too much K can hinder the absorption of calcium and magnesium). Too much potassium can also prevent the absorption of certain micro-elements, such as zinc. It is particularly important to take account of this interaction when using very hard water with a high calcium and magnesium content.

Phosphorus

An excess of phosphorus interacts negatively with the majority of micro-elements (Fe, Mn, Zn and Cu). In some cases, this is due to the formation of insoluble precipitates and in other cases, to metabolic processes in the plant which prevent the transfer of the nutrient from the root to other parts of the plant. This is the case, for example, with the P/Zn interaction. The P/Fe interaction appears to be negatively regulated at the cellular level and by the formation of insoluble complexes. The P/Cu interaction normally involves the formation of precipitates in the root area.

Genetic interactions can vary from one species to another and even between different varieties of the same species. For example, in some species a positive effect has been observed between the amount of available phosphorus and the plant’s resistance to salinity, meaning that an increase in this element leads to greater resistance. Other studies, however, conclude that the effect is negative.

There have also been reports of a reduction in the availability of sulfur and calcium when large quantities of phosphate are applied. In the case of calcium, this is caused by the formation of insoluble phosphates.

In contrast, phosphorus favors the absorption of magnesium, so a shortage of phosphorus could also lead to a magnesium deficiency if the latter is present in small quantities.

Both NO3- and NH4+ facilitate the absorption of phosphorus. In the case of NH4+, the reason appears to be the excretion of H+ ions by the plant when nitrogen is administered in this form in significant quantities. These H+ ions cause a slight acidification of the root area, which can favor the solubility of some phosphorus salts which would otherwise be trapped or remain in an insoluble form.

Root nodule. Colored Scanning Electron Micrograph (SEM) of a root nodule on a pea plant (Pisum sativum) caused by the nitrogen-fixing soil bacteria Rhizobium leguminosarum. The plant and the bacteria have a symbiotic relationship. The bacteria convert (‘fixes’) atmospheric nitrogen in the soil to ammonia. The plant cannot carry out this process itself, but it is vital for the production of amino acids, the building blocks of proteins. In return, the plant passes carbohydrates produced during photosynthesis to the bacteria for use as an energy source. The bacteria enter the plant through its root hairs, where an infection thread leads it to the nodule.

Magnesium

It is also important to take account of the Ca/Mg ratio. Its most important effect is its influence on the soil structure. Calcium in the soil tends to improve aeration, while Mg favors the adhesion of soil particles. Thus, if the Ca/Mg ratio is very low, which means that much of the exchange complex will be occupied by these Mg ions, the soil becomes less permeable, harming the development of the crops. Because of this, the Ca/Mg ratio should always be kept above 1.

This ratio is also important for the mineral balance within the plant. The Ca/Mg ratio in the leaves of some plants is about 2:1, which means that it is necessary to apply greater quantities of calcium than magnesium via the nutrient solution.

Magnesium uptake is also influenced by Zn and Mn levels in the growing medium; an overdose of these micro- elements, as well as being toxic, could also reduce the plant’s absorption.

 

[ClassicT]

Interaction of Sodium with Calcium, Magnesium and Potassium
Sodium has a negative effect on most plants due to its toxicity, when it accumulates in certain tissues of the plant, and its capacity to harm the soil structure by competing with other cations for adsorption (the adhesion of the cation to the surface of some soil components). When a soil contains a level of sodium that might prove harmful to crops, it is said to be sodic. Soil sodicity should not be confused with soil salinity, which refers to the total quantity of salts in the soil, without specifying which salts are more prevalent.

There are two ways of determining where there is a risk of harm from excess sodium. One is by calculating the ratio between the sodium and other dissolved cations that will be absorbed by the plant. This is known as the sodium adsorption ratio or SAR. The formula is as follows:

Irrigation water with a SAR over 18 is considered as having a high sodium content.

Another way is by calculating what proportion of sodium cations is retained in the exchange complex, as compared to others. This is known as the exchangeable sodium percentage (ESP).

ESP = 100 x Na / CEC
A soil is considered sodic if it has an ESP of over 15%.

Finally, the ratio between calcium, magnesium and sodium can be altered by the presence of carbonates and bicarbonates. In other words, even if there is initially more Ca and Mg than Na – in principle a good ratio for avoiding problems – if you irrigate with very hard water containing large quantities of carbonates and bicarbonates, they can make the calcium and magnesium precipitate in the form of insoluble carbonates, tipping the scales in favor of sodium and increasing the SAR.

This is known as the residual sodium carbonate (RSC) index. The formula is as follows:

RSC=(CO3-+HCO3-)-(Ca+2+Mg+2)
Tap water with values over 2.5 should not be used, as it can cause problems.

 

[ClassicT]

Ah! After reading that, I have an idea to correct my Ca toxicity problem. Flush with compost tea. If Ca has a double positive charge and negative charges exist in organic matter...

Is my line of thinking correct?

 

[xtsho]

You're way overthinking this. It's a weed. If you think you've fed too much nutes then feed plain water. Dumping more stuff on your plants rarely has the desired effect.

 

[OldMedUser]

In my grow, these bad interactions and lockouts only started occurring midway through flower.

What was happening to your plants midway through flower?

Avoid a lot of problems by using decent water like RO.

 

[ClassicT]

What was happening to your plants midway through flower?

Avoid a lot of problems by using decent water like RO.

I inadvertently gave them a shit ton of calcium. It’s causing lockout of Mg, Mo and N and P. My thick stubborn head tried to give them a light dose of what they were lacking, still not getting that they have that shit, they just can’t get to it because of the Ca. I get it now.

My new mantra is “just water, just water, just water”.

And yes, I’ve been using tap. With 9 plants in 10 gallon pots I don’t want to have to buy that much RO water.

Just a thought, isn’t the water in my dehumidifier, at least, distilled? What do you think about watering with that? Again, just a thought. Thanks for participating in my thread OldMedUser. Peace.

 

[OldMedUser]

Just a thought, isn’t the water in my dehumidifier, at least, distilled? What do you think about watering with that? Again, just a thought.

I don't use a dehumidifier but have come up with a design to collect the water in my exhaust for at least the 9 months a year it's cold enough to condense water in the exhaust. No reason you couldn't re-use the water from yours tho. It's basically distilled water and other than what's in the air you breath in there shouldn't have anything bad in it unless there is some minor aluminum contamination from the cooling coils. Al is everywhere in soils all over the world so I doubt a bit in the water would hurt anything.