Fertilizers for seedlings x mature plants

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mmcavall
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Fertilizers for seedlings x mature plants

Post by mmcavall »

A friend of mine is a technician in hydroponics and will help me design and prepare fertilizer solutions to give to my plants.

He knows everything about fertilization of flowers, fruits and vegetables, but knows nothing about cacti and succulents, so it is my job to tell him what are the needs of these plants.

I know they must receive little fertilizer, and Nitrogen must be seriously controlled. But I don’t have to many information beyond this, and would like any advice.

I would like to prepare two solutions, one for the mature plants and one for the seedlings. Or even a third solution if necessary. Does this make sense? What would be the recommendations? What would be the main differences between fertilizer solutions to seedlings and mature plants?

One of his products is NPK 08-10-40 + 1.8 Mg + 2.4 S
The other is Monoammonium phosphate (MAP), which is 12 N and 60 P
and the third is calcium nitrate, which is 15 N and 19 Ca

He will mix them up in adequate proportions to obtain a solution with correct amounts of macro and micronutrients.
I should tell him for example “prepare a solution with NPK 2 – 7 – 7 plus micronutrients” ...

Thanks again for any comments and help
iann
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Re: Fertilizers for seedlings x mature plants

Post by iann »

First, goes without saying but I say it anyway because so many people get hung up on it: the size of the numbers doesn't matter, only the ratio. 7-7-7 is exactly the same as 20-20-20 except you wouldn't dilute as much. Once you have your finished fertiliser, you'll need to work out how much to dilute it. Something in the range of 100ppm of each of the main nutrients is good, although you can use a more dilute feed if you do it more often. More vigorous plants than my favourite Lithops and small cacti might get a bit more, but remember you aren't growing tomatoes ;)

Any reasonably balanced fertiliser should do for seedlings. They need to grow so don't starve them of nitrogen. Also, consider what is already in the soil and don't overfeed if they already have a lot of nutrients on hand. Seedlings will do well with frequent application of a very dilute soluble fertiliser. Micronutrients are important, but depending on your soil you may not need them. Adding them at any sensible level is unlikely to cause problems though.

Adults can do well with much the same fertiliser, but with a few possible variations. You would rarely want to use a fertiliser with more nitrogen than the other main components, which is something that is fine for seedlings. Some people do apply nitrogen-only feeds but these must be extremely dilute to avoid excessive or unhealthy growth. Try to avoid faddy types of feeding over the longterm - a dose of something that a plant has been lacking might work great once but could be damaging if you keep doing it. Perhaps for faster growth of young leafy succulents like Adeniums or Crassula, you might use extra nitrogen. Otherwise keep the nitrogen at the same level or below the other numbers. Micronutrients, especially magnesium, are more important for adults, they will usually be sitting in the same soil for a very long time and can run short of anything that you don't top up regularly.

For adults, providing a soil that already contains appropriate nutrients is a better solution. It will give them a steady trickle of nutrients rather than risking boom and bust whenever you remember to (over-) feed them. It also avoids problems with evaporation leaving behind salt buildups as a soluble fertiliser is left in the soil instead of going into the plants.

I mostly use 12.5-25-25 plus micronutrients and I have a liquid balanced feed mostly for seedlings. I don't fertilise a whole lot because my soil mix comes with a decent load of fertiliser, but it runs a bit thin after a couple of years.
--ian
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mmcavall
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Re: Fertilizers for seedlings x mature plants

Post by mmcavall »

Thank you very much, Iann, very good information, the kind of explanation I needed.
From what you said I have new questions.

1)
7-7-7 is the same as 20-20-20, and I’ll dilute this to reach about, let’s say, 100 ppm of each component at the final solution. But if I use 12.5-25-25, I’ll have 50 -100 -100 ppm, right?
So the proportions are important because at the final solution I’ll have different (or equal, depending on the formula) ppm values for each component, and this balance is important.
Did I understand correctly?

2)
Different plants or different phenophases will have different nutrients requirements, right?
But if I try a generalization, it would be possible to define ideal ppm of each component for, let’s say, seedlings, mature (maintenance), mature (flowering)?
What would be these formulations?

for example:
seedlings: 10-10-10
mature (maintenance): 10-20-20
mature (flowering): 04-14-08

It would be possible to give some general advice in this sense? (ignoring soil composition, etc?)

Or: since my soil is sufficently fertile, I dont need to give much N, and, in fact, it would not be good to to that, so even the seedlings would benefit from 04-14-08 (more than from 10-10-10)?

3)
What about the other components? My concern is mainly about Calcium.

Thanks again,
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greenknight
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Re: Fertilizers for seedlings x mature plants

Post by greenknight »

If you think your soil is lacking Calcium, you could add a little gypsum to your mix - long-lasting source of Calcium and Sulfur, doesn't alter the pH.
Spence :mrgreen:
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mmcavall
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Re: Fertilizers for seedlings x mature plants

Post by mmcavall »

thanks, Spence, I think I did'nt expressed clearly. I dont know wheter is lacking Ca or not. I just asked because we always talk about NPK but rarely about the other components and Ca may be important.

Anyway, I've done a good research and found out that every grower will have its own opinion. There are many different ways to feed our plants (some are wrong!)...i.e. there is no simple recipe and I'll have to try some and make adjustments.

Hope to post here some results in the future,

thanks again
Marcelo
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greenknight
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Re: Fertilizers for seedlings x mature plants

Post by greenknight »

Ca is very important, but it's relatively abundant in most soils. It's just that I noticed that the Ca source your friend uses also supplies N, and you don't want too much N. Your mix may provide enough Ca, but if you're not sure it does, a small amount of gypsum added to the mix wouldn't hurt.
Spence :mrgreen:
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mmcavall
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Re: Fertilizers for seedlings x mature plants

Post by mmcavall »

thanks Spence for your advices!
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mmcavall
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Re: Fertilizers for seedlings x mature plants

Post by mmcavall »

So here are the formulations proposed by my friend to me to use with my plants:

(ppm indicated is reached when I dilute a given amount of the products in a given amount of water, not indicated here for simplification)

Formulation 1: NPK “7 - 7 – 7”
EC: 0,75
Total N: 69,9
NO3: 57,2
NH4: 12,7
N2: 0,0
P2O5: 68,5
K2O: 70,0
Ca: 57,0
Mg: 3,15
S: 4,20
Cl: 8,23



Formulation 2: NPK “12.5 - 25 – 25”

EC: 1,68
Total N: 123,6
NO3: 85,6
NH4: 38,0
N2: 0,0
P2O5: 254,0
K2O: 248,0
Ca: 47,5
Mg: 11,16
S: 14,88
Cl: 29,14



Formulation 3: NPK “11 – 32 -34”

EC: 1,86
Total N: 112,0
NO3: 68,0
NH4: 44,0
N2: 0,0
P2O5: 325,0
K2O: 340,0
Ca: 0,0
Mg: 15,30
S: 20,40
Cl: 39,95

What do you guys think about it?
Any recommendation for dilution (NPK ppm at final solution)?
Any recommendation for frequency of fertirrigation?

(Ok I know all this answers will depend on several factors, but any comment or advice in general manner will help too much).

Thanks again,
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mmcavall
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Re: Fertilizers for seedlings x mature plants

Post by mmcavall »

for the formulation 1, in the final solution I'll have 69,9 ppm of N, 68,5 ppm of P and 70 ppm of K (in the case it is not clear above)
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mmcavall
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Re: Fertilizers for seedlings x mature plants

Post by mmcavall »

I’ve started adding very diluted fertilizer in the tap water.
I used the “C” solution above, but diluted to ¼ (which means 28 ppm of N, and about 80 ppm of P and K).
I’ve noticed some quick new growths in plants that were standing for a long time. Some pictures:
Image

Image

Image

It decided to bloom:
Image

I can’t say for sure whether these are responses to fertilization alone or responses to fertilization plus light shade clothing I add plus the arrival of spring/summer.
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