Simple questions about fertilizers

[Korleone]

Hello.

I have some simple questions about fertilizers.

For the last few days I've spent a lot of time figuring out idea profiles for fertilizers for indoor tomatoes.

I wrote a program that figures out how to mix seperate fertilizer together to better match your custom fertilizer profile. Which i great (and bloody genius), but..

.figuring out an ideal fertilizer profile for tomatoes is difficult. Lots of info online is contradictory.

Typically, tomato fertilizers on the shelf are 3-2-5.

For instance, Phostrogen Plant Food and Chempak Tomato Food are clos to a 3-2-5, have trace elements and seem like great plant foods fo tomatoes.

But the fortnightly dose is 516ppm-328ppm-829ppm. So all at once, tha concentration is added to the soil. Why isn't that a problem?

(That was the first simple question. Here comes the second.)

Why is it better to feed a plant with emphasis on a particula nutrient?

Isn't the plant going to take what it needs? In other words, if yo use a balance fertilizer, say, 6-6-6 at 100ppm, and the plant need more Potassium, couldn't you just increase the concentration of 6-6- to, say, 150ppm instead of changing to a fertilizer that's, say, 6-6-8

Simply what I'm asking is: does a plant take only what it needs fro the soil, or does a plant eat everything it's given?

If the first is true, then we need only use a balanced fertilizer an increase the ppm to suit. If the second is true, then altering th ratio and the ppm would be necessary.

Btw, I know most of you are organic growers. This is just an exercis for me, to figure this out. So please, you don't need to tell me o the evils of non-organic fertilizers

-- Korleone

[Billy]

Well, then you already know the answer. But why ask a question if you already know the answer? There can only be one answer for that ;-)

[David Hare-Scott]

Why? What is the need for this?

Why would it be?

It isn't necessarily. Sometimes it is.

Different plants require different proportions of nutrients. For example things with lots of green leaves (eg grass) need more nitrogen. Also overdose can be harmfull and not just at the level that is toxic, for example carrots grow strange, twisty and bifurcated if over fertilised. The shotgun approach (hit 'er with some more of everything) is at best wasteful and can be disasterous.

One key thing you have left out is the existing nutrients available in the soil. Plants don't get only what is added as fertilser, nutrients come from many sources, some plants even have little mates that make nutrients for them. Also different soils bind nutrients to various degrees. This means there is no such thing as "ideal" tomato fertiliser or anything else fertilser. And texture and drainage make a huge difference. And lots more, this matter is much deeper than it first looks.

Writing your own software is admirable. May I suggest that whatever you write will be far more useful and you will learn far more from doing it if you understand the subject matter that you are modelling or work from a specification written by someone who does. There is much more to good software than kool kode and a fAnCy iNTerFAce.

David

[Korleone]

The question wasn't specific to non-organic methods. It was about plan

behaviour generally. If there was only one answer, you didn't have it. :)

Besides, I've figured it out. Plants are gluttons. They will eat al they can. They can't pick and choose, otherwise there would be no suc thing as nute burn. Adjusting NPK ratios and/or ppm is necessary for nutrient deficiency. Pretty obvious really, but I forgot abou overdosing.

Fertilizing can be a difficult thing. You want to give your plant what they need in optimal doses but not too much of a good thing. There's no exact formula to it, but you should be aware of roug guidelines. Listening to the plants is one thing, but knowing how t push your plants to the top of their potential without pushing the over a cliff is another.

The same goes for raising children I suppose. Except you can't ea them(legally)

-- Korleone

[Korleone]

Well.. If I wanted to experiment with a particular fertilizer profile but i wasn't available commercially I could mix my own using separat fertilizers. Figuring out how to balance them with pen and paper woul take a very long time to do accurately. So now, I can take an fertilizers and find out the best possible way to combine them to ge the profile I want.

That's not much of an answer. I was asking if it would be a problem. I'm assuming if you dump a large amount of any particular element int the soil, the plant is likely to die, right? So isn't that a larg amount all at once?

Yes, you're right. Soil is complex stuff. However, when I say ideal I don't mean a-cure-for-all-ills fertilizer, just the best ballpar figure for my particular setup.

I want to be able to decide on a great N-P-K-Ca-Mg-S ratio, and the only have to adjust the ppm as the plant grows. I won't be able to us it all of the time of course. I know that. But, I will be able to us it most of the time in a controlled setup.

It's definitely not about interface. :) Just a bog-standard number cruncher.

It simply figures out the best matching ratios. It?s not about modeling at all, really.

It?s not like I?m building a soil model. That would be completely unnecessary and altogether useless.

[Billy]

Spunky little ignoramus ain't you?;o)

Learned yourself up on macro-nutrients, eh?, and now you know farming up to 1930. I hope you do your farming hydroponically and leave the soil alone. Organic gardening means, "take care of the soil, and the soil will take care of your plants". But you already knew that, humm?

Well here is the tip of an iceberg for you: "Harsh chemicals can scorch young leaves, and nitrogen fertilizers render lettuces more vulnerable to insects. It seems the bugs are attracted to the free nitrogen in their leaves, and because of the more rapid growth of chemically nourished plants, insects find their leaves easier to pierce." - Omnivore's Dilemma, pg. 165.

Your reading list:

Teaming with Microbes: A Gardener's Guide to the Soil Food Web Jeff Lowenfels and Wayne Lewis

Omnivore's Dilemma: A Natural History of Four Meals by Michael Pollan (Not a book) The Worst Mistake In The History Of The Human Race .pdf

Keep us appraised of your success ;o)

[Korleone]

I'll repeat myself, juuust so we're clear he THIS HAS ABSOLUTEL NOTHING TO DO WITH THE ARGUMENT FOR OR AGAINST ORGANIC METHODS.

I didn't mention once that I was interested in fertilizers that weren' of animal or plant origin. In fact, my question has nothing to do wit fertilizers. I asked a simple question on how plants work.

I understand your pedestal must be very comfy, you clearly kno everything there is to know about horticulture and you were born wit this knowledge and God forbid anyone should know any less.

btw, ... THIS HAS ABSOLUTELY NOTHING TO DO WITH THE ARGUMENT FOR O AGAINST ORGANIC METHODS.

Just wanted to pop into a nice gardening forum, ask some friendly an simple questions. Friendly. Simple. Yes?

I am actually grateful for the reading list however.

I recommend the following:

not available on Amazon, but I recommend you look out for these: Growing the Dogmatic Way by Yura Duszbahg, and The Real Wiccan's Guide to Dryhumping Your Opinion Into Ever Conversation.

Please don't reply. I really can't be bothered. And if you do reply, it's sort of, in a way, basically the same a admitting to child abuse. If you think about it

-- Korleone

[Billy]

This is for the group, not the prima donna who apparently has found time to take a psychology class. Psychology classes are usually populated by people who have questions about themselves as sociology classes are populated by people who have questions about other people.

Naked in his/her ignorance s/he attempts to deflect attention by misdirection, and then vaunting his/her ignorance, by citing two nonexistent books. The "Heart of a Lion" (what do you think psychology students?) is reduced to the timidity of a mouse. I think we do an excellent job answering honest questions about gardening. We answer honestly from our hearts, even if we don't have citations. Why someone would try to abuse our service by posing as competent, and then framing ill defined questions is beyond me, even if they are an ignoramus.

[David Hare-Scott]

If you know what the deficiencies of your soil are and the needs of your crop are element by element and you are going to align the two using only your custom mix then I can see that your software may be useful. In practice none of those three conditions are likely to be true.

I don't understand. You seem to be talking about two processes, is that right? What is the first one where you get "great ratio"? How do you subsequently adjust the "ppm", how would you know what it is at any time? Do you think that the elemental content of your soil as determined by some assay method is what is available to the plants?

I won't be able to use

Controlled setup? Are we talking hydroponics here? That's rather different.

Yes it is by my definition of 'model'.

I wasn't hinting that you ought to be modelling soil composition in relation to growing plants and adding fertiliser in its entirety. However, any software that supports decision making about a real-world situation is modelling that situation in some way. It embodies certain data that are collected out of a much larger conceivable set, it makes simplifying assumptions, uses selected formulae, produces a set of results out of a much larger possible set, etc. Modelling is about choosing to deal with a manageable assembage of what is important to you out of a larger system and showing (or trusting) that what you ignore will not mess it up too much.

I am suggesting that, for example, you may not have looked carefully at what your assumptions are and what affect they will have on the real-world usefulness of your results.

David

[Angello Huong]

Overdosing too much nutrients/minerals into the soil can block the absorption rate of other nutriets/minerals from the soil. There is an optimal balance between the ppm of the various & minerals that will result in the maximum uptake efficiency of the plant.

Also, too high of a concentration can lead to the soil containing too much dissolved salts, and water then has to come out of the plant in order to restore the osmotic balance--causing plant burn and dehydration.

[Wilson]

sometime in the recent past Korleone posted this:

Not a word on pH. If it isn't right, nutrients can get locked up so they aren't available to the plant at any ppm. Just 2 cents.