Info on S/H fertilization

[hypostatic]

Originally Posted by DavidCampen

And it depends if you are using RO water or not. If you are using RO water then you definitely need a fertilizer with significant amounts of calcium and magnesium.

Ah this is good to know. I think I will be using RO/DI water, so should I be preparing the fertilizer a bit stronger to compensate for RO/DI water that should not have ions?

Originally Posted by DavidCampen

I never used the MSU formulation products because they come as powders that were not prepared by spray drying so that I would expect a lot of physical segregation of the individual components in the package.

Sorry for my ignorance, but are you saying that you've never decided to use the MSU product because it's a powder that is hard to dissolve in water?

[DavidCampen]

Originally Posted by hypostatic

Ah this is good to know. I think I will be using RO/DI water, so should I be preparing the fertilizer a bit stronger to compensate for RO/DI water that should not have ions?

Not stronger; but many fertilizer formulations do not contain the amounts of calcium, magnesium and other minor but essential elements that are needed when you are mixing with RO water

Sorry for my ignorance, but are you saying that you've never decided to use the MSU product because it's a powder that is hard to dissolve in water?

Not because it is hard to dissolve, it is not AFAIK. It is because as a powder the various components - potassium nitrate, potassium phosphate, copper sulfate, manganese sulfate etc. could conceivably separate so that the material in the package would not be homogeneous. I do not know that this is the case with any particular powder formulation but it was a consideration when I decided to use Dyna-Gro.

[Ray]

David is correct that the MSU ferts are a mixture of ingredients, not spray dried solutions, so someone not taking a little extra care might apply varying chemistry, doe to dose.

However, make a liquid concentrate from the powder, and let down yourmfinalmsolutionsnfromthst, and you're OK.

[hypostatic]

Ohhhh ok I think I get it. You're saying that the fertilizer is a mixture of the anhydrous salts, which might be mixed heterogeneously, so each tablespoon of the powder might differ in individual salt concentration?

Originally Posted by DavidCampen

Before I started formulating my own fertilizers I used the Dyna-Gro Orchid-Pro formulation since the Dyna-Gro products are liquids.

What formula do you use?

[DavidCampen]

The batch I made this weekend was:

50 g Calcium Ammonium Nitrate (15.5-0-0-19Ca)
20 g Magnesium Nitrate (11-0-0-0Ca-9.6Mg)
15 g Potassium Nitrate (14-0-46)
10 g monoPotassium Phosphate (0-52-34)
25 g Ammonium Aspartate
2 g Ammonium Sulfate (21-0-0 24S)
4 g Ammonium Citrate
also minor elements:
200 mg Iron (from Ferrous sulfate)
100 mg Manganese (from Manganese sulfate)
100 mg Sodium Chloride
50 mg Zinc (from Zinc sulfate)
50 mg Copper (from Copper nitrate)
50 mg Boron (from Boric Acid)
5 mg Cobalt (from Cobalt Sulfate)
5 mg Molydenum (from Sodium Molybdate)
5 mg Nickel (from Nickel nitrate)

Diluted to 2 liters with RO water to make a concentrate that will then be applied at 1:100 (so final dilution is to 200 liters) with every watering.

The formulation's composition stated as N-P-K-Ca-Mg-S (and given as grams per 2 liters of concentrate, not as a percentage) is:
16-5-10-9.5-2.4-0.5

For the next batch I want to increase the calcium a bit and decrease the magnesium a bit to get a 5:1 ratio of calcium to magnesium.

[ALToronto]

That's pretty impressive, David. I have a few questions, both general and specific.

1. Where do you buy small quantities of all these chemicals? I can easily buy 50+ lb bags of each of them, but not 500 g

2. In light of the K-lite idea and experiences, are you planning to reduce the potassium content of your fertilizer? Have you tried blending and using it with less K?

3. Why would you add NaCl in any quantity? Does it actually do anything positive to plants? Or any chloride, for that matter?

4. Have you tried using a potassium silicate as your source of both K and Si?

5. What is an aspartate and what does it do?

Don't take these questions the wrong way, I am genuinely curious about your reasons for selecting these specific ingredients.

[Paddle_grl]

I've never soaked my medium in any type of root stimulater. I use Orchids Focus Grow/Bloom at full strength 2tsps in a gallon of water. I have hard water at my house so that's not an issue for me. I think the ratio's are 2-1-2 and 2-0.6-2. I just make a gallon jug and water them weekly and they seem pretty happy. I have 9/10 orchids in S/H. I've been doing this with some of them for 4 years now and they all seem to like it. But I'm not quite as advanced as some.

[DavidCampen]

Originally Posted by ALToronto

That's pretty impressive, David. I have a few questions, both general and specific.

1. Where do you buy small quantities of all these chemicals? I can easily buy 50+ lb bags of each of them, but not 500 g

Some places in the U.S. that I buy chemicals from; but you will likely have more difficulty in Canada.
Buy Specialty Nutrients - J. R. Peters Inc. Fertilizer Products And Services
Fertilizer Compounds
Pottery and Ceramic Raw Materials
https://www.lorannoils.com/p-8273-ba...te-powder.aspx
General Chemicals from The Science Company® ASC&p=6
Calcium Nitrate 15.5% Nitrogen,19% Calcium 5 pound bag!

2. In light of the K-lite idea and experiences, are you planning to reduce the potassium content of your fertilizer? Have you tried blending and using it with less K?

In my opinion, the potassium toxicity thesis that led to the formulation of the so called "k-lite" has no basis in fact. So I have no plans to reduce the amount of K in my formulations.

3. Why would you add NaCl in any quantity? Does it actually do anything positive to plants? Or any chloride, for that matter?

IIRC, a small amount of chloride is essential. A small amount of sodium is at most beneficial but not essential so I could have use potassium chloride instead.

4. Have you tried using a potassium silicate as your source of both K and Si?

Silicate will form very insoluble precipitates with many of the cations in a fertilizer formulation. It is a mystery to me how plants manage to take up silica; I can only guess that they must manage to take up nanoparticles of insoluble silicates. If I were to try to apply supplemental silica I would do it separately from the normal watering/fertilizing routine.

5. What is an aspartate and what does it do?

Aspartic acid is an amino acid. I am using it to chelate the minor cations as well as calcium to reduce there tendency to form insolubles that are not available to the plant. Commercial formulations tend to use EDTA to chelate the minor elements but I feel that the stability constants of the EDTA chelates are too large possibly making it difficult for the plant to extract the essential elements from the chelate and especially since I am adding a chelate in large quantities to bind calcium I beleive that EDTA in those quantitities would be detrimental. Aspartic acid chelates have lesser stability constants than EDTA chelates and so I feel that it is more suitable for use in large quantities. One problem of adding aspartic acid is that the nutrient solution now contains a carbon source in addition to nitrogen and other nutrients so it will readily support the growth of fungi, I have to store the nutrient concentrate as an aseptic solution or it will start growing mold or fungus.

[hypostatic]

Originally Posted by ALToronto

1. Where do you buy small quantities of all these chemicals? I can easily buy 50+ lb bags of each of them, but not 500 g

I think you can buy most of those chemicals on amazon.com.

For David:
Hey, just so I can better understand your formulation, this seems to be the percent solution that you want (before 1:100 dilution):
Nitrogen: 0.008%
Phosphorus: 0.0025%
Potassium: 0.005%
Calcium: 0.005%
Magnesium: 0.001%
Sulfur: 0.000025%
N-P-K-Ca-Mg-S : 16-5-10-10-2-0.5

Could a fertilizer be made with potassium chloride, calcium chloride, magnesium chloride, ammonium nitrate, phosphoric acid, and sulfuric acid as the main sources of the elements?

[DavidCampen]

Originally Posted by hypostatic

Hey, just so I can better understand your formulation, this seems to be the percent solution that you want (before 1:100 dilution):
Nitrogen: 0.008%
Phosphorus: 0.0025%
Potassium: 0.005%
Calcium: 0.005%
Magnesium: 0.001%
Sulfur: 0.000025%
N-P-K-Ca-Mg-S : 16-5-10-10-2-0.5

At final dilution I think in ppm, before that only as ratios but the percentages you gave above look like what you would have at the final dilution of 200 liters.

When I calculate ppm I use weight to volume but for dilute aqueous solutions this is equivalent to weight to weight. I would work with percentages also as weight to volume being equivalent to weight to weight.

So to work backwards from the percentage you gave;200 liters of 0.008% N solution is 200,000 grams whch would be 0.008 grams of N per 100 grams of solution or 0.008 * 200,000/100 = 0.008 * 2,000 = 16 grams N. So that percentage is the final dilution. But I would have said 80 ppm N.

ppm is easy to calculate, 1 gram per liter is 1000 ppm, 1 milligram per liter is 1 ppm. So 16 grams N in 200 liters is 16,000 milligrams in 200 liters = 80 milligrams in 1 liter = 80 ppm.

Could a fertilizer be made with potassium chloride, calcium chloride, magnesium chloride, ammonium nitrate, phosphoric acid, and sulfuric acid as the main sources of the elements?

Far too much chloride. You need Calcium Ammonium Nitrate, Magnesium nitrate and Potassium nitrate.

You could use phosphoric and sulfuric acids for those elements but then your solution will be too acidic and you will have to add potassium hydroxide to adjust the pH. Better to use potassium dihydrogen phosphate and ammonium sulfate.