Yellowing is not neccessarily a lack of N.

[ImaginaryFriend]

Super fun thread.

"Thanks," to the contributors.

Very useful discussion for my understanding of 'yellowing'.

 

[Pinball Wizard]

8 weeks ....

 

[Scrappy4]

I'm two weeks in flower on a grow that has leaf yellowing. This is the 4 generation of this plant. The first two gens did very well with normal yellowing around week 6, and since my re-using my re-amended soil the problems arose. I'm pretty sure this grow has also been the victim of too hot of soil. In veg the main symptom was slow growth, but nice healthy looking leafs of dark green. Now in flower they budded early and stopped the stretch early. I wonder if an over abundance of nutrients leads to the plant not taking up the normal amounts than a more appropriate soil. And that leads to the early yellowing of the leafs.

The third generation also had similar symptoms but I wrote it off too mites/heat/ph. The yeilds went from 16 oz to 9. But now the only constant that remains seems to be the re-amended soil in gen 3&4.

The soil was a blood/bone/kelp meals with EWC, lime, and epsom salt, on the re-admend, I added these again and bloom/flower guano and greensand..........scrappy

 

[VerdantGreen]

Totally agree. Below a certain mass of soil eg pot culture - many other considerations to make. I think the more important one being root binding.

I wonder now just how little nutes are actually needed when the microherd is a large and mature beasty like mine.

....

hey mr F i would agree about rootbinding being a major factor. if your plant is rootbound then you are trying to run the race without legs really.
the other factor i would theorize is important is the type of N avaiable. afaik ammonia N is one nutrient that the plant cannot selectively exclude - i.e. it will diffuse into the roots above a certain level. many pot culture grows (including mine) will add 'strong' ferts like guano or blood meal - because im pretty certain compost alone wil not be enough to sustain a plant in a 3 gallon pot through flower. (or at least if i added more than 20-25% compost to my soil mix in the form of mushroom compost or EWC then it would make the soil too wet and heavy) .

so if there is an excess of ammonia N in the soil towards the end then that could effect the quality of the smoke? i notice your soil tested very low for that.

VG

 

[ixnay007]

Plants can block the ammonia N uptake, ancient evolutionary trick to stop yourself from croaking when a dino took a leak on your roots.

 

[VerdantGreen]

hi ixnay, im no expert on this but i thought that above a certain level it entered the plant by osmosis/diffusion. this made sense to me because ammonia is incredibly soluble.

anyone??

p.s. love your siggy quote, very true

 

[guest2012y]

hey mr F i would agree about rootbinding being a major factor. if your plant is rootbound then you are trying to run the race without legs really.

I'm finding out more and more how true this is. Most all of my premature yellowing ladies are in root bound pots. The ones with extra root space to use in flower never yellow out before their time.
Comes back down to the type/pot size/how big when flowered ratio in these cases.

 

[MrFista]

I'm two weeks in flower on a grow that has leaf yellowing. This is the 4 generation of this plant. The first two gens did very well with normal yellowing around week 6, and since my re-using my re-amended soil the problems arose. I'm pretty sure this grow has also been the victim of too hot of soil. In veg the main symptom was slow growth, but nice healthy looking leafs of dark green. Now in flower they budded early and stopped the stretch early. I wonder if an over abundance of nutrients leads to the plant not taking up the normal amounts than a more appropriate soil. And that leads to the early yellowing of the leafs.

The third generation also had similar symptoms but I wrote it off too mites/heat/ph. The yeilds went from 16 oz to 9. But now the only constant that remains seems to be the re-amended soil in gen 3&4.

The soil was a blood/bone/kelp meals with EWC, lime, and epsom salt, on the re-admend, I added these again and bloom/flower guano and greensand..........scrappy

Hi Scrappy. Adding the same amount of dolomite etc every grow will certainly lead to problems. You probably just need to dilute that soil mix about 50/50 with compost if you have only the 4th run going now.

Plain water for the rest of the grow. The mix might be too basic though... Test pH. If it's above 7 take a look at what Verdant is doing with citric acid in the citric acid thread and do the same.

Plants use a lot less than we pour on. The bulk of plants is carbon hydrogen and oxygen (shit he didn't say NPK) and all of these are freely available from water and carbon dioxide. Get the soil right my belief is the N becomes free too. Fungi make P available and will likely take years to use up what's in the average guano growing mix. So the other majors are Ca and K. What to do for these? Add bananas, leafy greens and eggshell/oyster shell to your worm bin.

What a plant will actually require it's so minimal compared to what we've been told to add. We massively overfert to make up for poor microbiology and the inefficiencies that come about due to this.

It's not just microbes leading to efficiencies though. The substrate has much to do with it as we've been learning from spurr. CEC rate, porosity, particle sizes, available water vs bound water... it gets complex!

Lean towards less ferts on addback. I went from full strength to half the recommended amount (for run one) on run two. however I have char in the mix so I'm more secure about my soil having 'reserves'. I and a friends soil experiments both crashed in the past trying to recycle at full strength nutes.

Now I'm down to no addbacks but that is misleading. I'll still be feeding my worms designer ingredients (chitin, leafy greens, char, bananas, fungus) and this is used then poured on, up to 2 cups at a time, three times per grow, via compost tea. The tea also gets a wee bit of molasses and kelp and fulvic/humic if I have them. So I am adding nutes, albeit, far less than is typical. In addition to this between grows the rootball is recycled and a bit of molasses and kelp is added then. Plus a mulch layer, which worms will slowly drag down into the soil mass adding to it in this manner. So I'm still ferting the soil.

When you consider how much material goes into a couple handfuls of worm castings, most the gases and water have gone but the plant doesn't need these in fert form remember it makes it's own carbs, so you got these castings representing the nutritional goodness from a large volume of vegetable matter and other ingredients. What else will your plants need, really.

 

[Scrappy4]

Thanks Mr Fista very good advice, I appreciate your response.

The soil for the next run has already been mixed 50/50 with straight pro mix. (good?) I'm almost to the point of shit canning the soil, and start anew. I really hate to do that though. Thoughts?

I was at a loss for re-amending the soil and all I read was that people did re-amend, and since that guano tea was so good in flower for the first two grows, I probably added too much to the soil. Plus I read that you could not harm your plants with organic nutes. I guess that was wrong, eh?


On this current grow, I'm starting to water heavy every three days, that is water till I get run off in 5 gallon smart pots. Rain water 6.5 ph on a cheapo dropper ph test. Soil is ph 7 on a cheapo soil probe. I freely admit slightly better than a wild assed guess. Flushing is a bitch with a scrog grow in a grow box and a severely bad back. The newest growth does look greener but I don't think I'm safe yet.

And lately after reading on this forum, I doubt I'm alone, seems like a common problem. Thanks again........scrappy

 

[MrFista]

It's the longer term ingredients, dolomite lime, P, that cause the real problems with addbacks. Things get out of balance. Outdoor traditional gardening it's more an annual thing throwing lime and stuff about most of the action coming from compost. Beds get rested or cover cropped. Indoors we crop more frequently, and so liming etc can be overdone quickly. So how does one go about continuously using soil indoors, crop after crop?

The best advice I can give is the best things that worked for me with recycling soil. I wanted long term, and when I learned the Terra Preta soils of South America have been fertile for centuries - I figured that's what I want to attempt. The thread in the stickies covers that subject well. Some bottled ferts helped in the start as I learned my way. But it's better not using them, they cost, they were a symptom of my lack of confidence in the soil microbes. But it takes a while to get cocky...

watch me crash and burn bwa ha!

But to gain that soil biology that makes Terra Preta so good, the amazing diversity that functions in Terra Preta soils - how? I don't think you can directly create the same biology but what you can do is add your local biology, and that works just peachy! How? Worm castings, and compost teas. It's important to get these right, there's teas that kind of help and teas that will blow you away with what they can do for a troubled garden. But when the soil has too much nutes, teas are a bad route for the immediate crop.

Properly made castings, then properly made teas made with those castings, that's the only way to do it imo, the store bought castings and resultant teas are crap by comparison. Castings is easy, feed the worms well and just make sure the castings are finished properly. The tea article sticky will teach you how to make teas with them.

If plain water is helping your plants we've both diagnosed the problem correctly.

Half and half with something from a bag sounds a reasonable approach to helping the soil out if the bagged stuff isn't hot. I'm not familiar with US products though. A nice compost tea would go down a treat while that soil is resting between grows too.

If it were my soil I'd be hunting down some char for it. You can safely add up to 20% fine char to your wormbin and it will come out the other end in castings of pure soil magic. I shit you not.

So, you grow in beds and smart pots? Beds no till? Mulching is awesome for plants in beds. I think it'd help in pots even more to keep temps down for surface microbes and roots especially in veg.

What's your mobility like? Char crushing, water and tea prep etc can be a bit of labour involved. The char can be a one off thing (it's gonna outlast us all) or added incrementally, it is important to preamend. The worm route is awesome, just takes time. Teas and char, adding nutes hesitantly after the first rich mix... No more liming. Put eggshells in your castings and forget about liming. Good organic eggs help omega balance for your joints and bones and healing too so worth getting with/without a worm bin.

That's the advice I give everyone these days, it's gold. Learning about teas and learning about char. You get to read a lot of posts from a lot of smart people and get a real good picture of organics in the process. And beds and no till, I'm totally sold on this concept now. So much easier.

Beds on wheels would be awesome. How big do beds have to be to ensure a good microherd? MM worked it out. MM?

I got 16 sq ft, should be in range

Hope that helps, I'm pretty toasted.

 

[ixnay007]

hi ixnay, im no expert on this but i thought that above a certain level it entered the plant by osmosis/diffusion. this made sense to me because ammonia is incredibly soluble.

anyone??

p.s. love your siggy quote, very true

Dunno, might be talking about urea blocking, might be indirectly related..

Wilson and Walker (1988)Go used independent methods to monitor urea uptake in their model system Chara. Controlling the fate of 14C-labeled urea in short-term uptake studies, they showed that urea uptake was concentration dependent and followed biphasic kinetics, indicating the existence of high- and low-affinity transport systems. In parallel, biphasic uptake kinetics in Chara were confirmed by electrophysiological measurements, in which a sodium-dependent inward current appeared in response to urea (Wilson et al., 1988Go; Walker et al., 1993Go). Finally, Wilson et al. (1988)Go concluded that high-affinity urea uptake in Chara is electrogenic, active, and, because of repressed uptake rates under high nitrogen levels, also under metabolic control.

I'm sure I read something, maybe even here..

 

[VerdantGreen]

thanks ixnay, ill check that out...
---

took a snap today to illustrate another stimulus to senescence - lack of light.

here is a pic of the plant below one of my modular scrog screens
this plant is only 3 weeks into flower. im certain these leaves have been sucked dry by the plant because there is no light down there. it happens with nearly all my strains.

above the screen is, fortunately, a different story

VG

 

[ImaginaryFriend]

This is almost to simple to ask, but could I get a clarification on the use of the phrase 'root bound'?

Root bound used to mean to me when a plant has been left in a pot until its roots wrap the perimeter of the bucket... but with air-pruning mechanics so common place now, does it mean when there is no more room for roots to develop within the media... no more room to expand? No more land?

 

[VerdantGreen]

yeah, rootbound or potbound is when the roots outgrow a 'regular' type pot.

 

[VerdantGreen]

here is a post from spurr about ammonia N

No, plants can't self-regulate uptake of ammoniacal N (like ammonia and ammonium) and it becomes phytotoxic to roots (burns them) when the plant is not able to move enough sugar (from photosynthesis) into the roots to convert the ammoniacal N into plant usable forms. When there is a lack of sugar, or the uptake of ammoniacal N outpaces movement of sugar into roots, phytotoxicity sets in.

Ammoniacal N is what causes nutrient toxicity from N, not nitrates AFAIK. In terms of P, the plant can self-regulate uptake of phosphate anions and excess gets converted (at least most of it) and stored in plant tissue.

Plants can self-regulate uptake of (at least) nitrates, P, Ca, Mg, and probably K, but not ammoniacal N (e.g. ammonia and ammonium).

The plant will take what it needs when it needs it; if it takes in more than it needs it will store it in tissue for later use (esp. in terms of partially-mobile and fully mobile elements within plant tissue). Plant self-regulation of ion uptake doesn't mean the plant stops taking in 100% of said ions, but it can/does reduce uptake to small or great degrees.

FWIW, if ammonium and nitrate is co-applied the plant will take up the ammonium faster and use it faster. For the first few hours (ex. in a fresh hydro rez) the ammonium will increase uptake of nitrates, but then after a few hours ammonium will decrease uptake of nitrates by the plant. I assume this is because the ammonium is converted into amino acids and moved into the phloem, that in turn signals the plant to reduce uptake of N (as nitrates).

 

[ixnay007]

The thing about urea uptake was in a post in this forum, maybe in the gardening with microbes thread (I'm a stoner.. can't trust my memory ;D )

 

[ImaginaryFriend]

yeah, rootbound or potbound is when the roots outgrow a 'regular' type pot.

And in an airpruning pot, when it continues runs out of room to send out secondaries... when the root ball looks like rockwool?

 

[VerdantGreen]

yes i guess so, ideally each root wants to be surrounded by soil. when the roots are all pressed together in a mass than there isnt so much they can do in the way of feeding etc.

 

[MrFista]

Urea and ammonia are two very different species. Ammonia is said to be about 100 times more reactive than urea. Urea gives off ammonia in the presense of water. That's why I rate it as a rubbish fertiliser. One rain and your profits gas off.

 

[Scrappy4]

It's the longer term ingredients, dolomite lime, P, that cause the real problems with addbacks. Things get out of balance. Outdoor traditional gardening it's more an annual thing throwing lime and stuff about most of the action coming from compost. Beds get rested or cover cropped. Indoors we crop more frequently, and so liming etc can be overdone quickly. So how does one go about continuously using soil indoors, crop after crop?

The best advice I can give is the best things that worked for me with recycling soil. I wanted long term, and when I learned the Terra Preta soils of South America have been fertile for centuries - I figured that's what I want to attempt. The thread in the stickies covers that subject well. Some bottled ferts helped in the start as I learned my way. But it's better not using them, they cost, they were a symptom of my lack of confidence in the soil microbes. But it takes a while to get cocky...

watch me crash and burn bwa ha!

But to gain that soil biology that makes Terra Preta so good, the amazing diversity that functions in Terra Preta soils - how? I don't think you can directly create the same biology but what you can do is add your local biology, and that works just peachy! How? Worm castings, and compost teas. It's important to get these right, there's teas that kind of help and teas that will blow you away with what they can do for a troubled garden. But when the soil has too much nutes, teas are a bad route for the immediate crop.

Properly made castings, then properly made teas made with those castings, that's the only way to do it imo, the store bought castings and resultant teas are crap by comparison. Castings is easy, feed the worms well and just make sure the castings are finished properly. The tea article sticky will teach you how to make teas with them.

If plain water is helping your plants we've both diagnosed the problem correctly.

Half and half with something from a bag sounds a reasonable approach to helping the soil out if the bagged stuff isn't hot. I'm not familiar with US products though. A nice compost tea would go down a treat while that soil is resting between grows too.

If it were my soil I'd be hunting down some char for it. You can safely add up to 20% fine char to your wormbin and it will come out the other end in castings of pure soil magic. I shit you not.

So, you grow in beds and smart pots? Beds no till? Mulching is awesome for plants in beds. I think it'd help in pots even more to keep temps down for surface microbes and roots especially in veg.

What's your mobility like? Char crushing, water and tea prep etc can be a bit of labour involved. The char can be a one off thing (it's gonna outlast us all) or added incrementally, it is important to preamend. The worm route is awesome, just takes time. Teas and char, adding nutes hesitantly after the first rich mix... No more liming. Put eggshells in your castings and forget about liming. Good organic eggs help omega balance for your joints and bones and healing too so worth getting with/without a worm bin.

That's the advice I give everyone these days, it's gold. Learning about teas and learning about char. You get to read a lot of posts from a lot of smart people and get a real good picture of organics in the process. And beds and no till, I'm totally sold on this concept now. So much easier.

Beds on wheels would be awesome. How big do beds have to be to ensure a good microherd? MM worked it out. MM?

I got 16 sq ft, should be in range

Hope that helps, I'm pretty toasted.

I took all my soil and put it on our vegetable garden. Then went out and bought new stuff. I went light on the additions, so I have the ability to add teas when appropriate. Thanks everyone, I hope this helps out someone else with simular problems.

BTW found out something interesting about wiggle worm, worm castings, (a midwest brand) they are made locally and licensed to use the wiggle worm label, so all wiggle worm castings are not equal........scrappy