equation problem!

[puppasmurf]

Im trying to work out a equation for fertilizer application..

Blood n Bone has 8% N, and im after 85 N. So 85/0.08= 1062.5kg/ha

Now thats for 1 Ha. But im trying to get down to Litres. I'm really lost on how to convert Ha down to litres with the 1062.5kg/Ha

Thanks in advance.

 

[GOD HERE]

Well if I understand what you mean, that's easy, there are 100 liters in a hectoliter. So, if you're trying to convert it to liters:

1062.5/100 = 10.625 kg/l

So all in all, 10.625 kg per liter.

 

[puppasmurf]

hectoliter

Sorry I meant Hectares. I work with Hectares, but now im trying to convert down to litres. I was told to go down to cubic metres. 1Ha = 0.0001 m3 (Cubic metres). The I found out that 60Litres = 0.06 m3.

Now 1062.5kg of BnB to a Ha, my aim is to get from 1 Ha down to 0.06 m3 as thats the container the materials will be mixed in.

So if this is my crystal hopefully this problem will be solved

 

[SpicySativa]

A hectare is a unit of area (10,000 square meters), and a liter is a unit of volume. You can't simply convert one to the other.

 

[SpicySativa]

I would start with 2 tablespoons per gallon, assuming that's roughly 50/50 blood and bone meal. No math needed.

 

[puppasmurf]

A hectare is a unit of area (10,000 square meters), and a liter is a unit of volume. You can't simply convert one to the other.

Correct that's why im trying to convert Ha into m3. 1 Hectare metre is 10,000 Cubic metre. 1 Cubic metre is 1000Litres.

 

[hydrosoil78]

so you are mixing something in a cubic meter container maybe?, sounds to me like blood n bone are granule fertilizers not liquids. I think you are figuring out how to spread lots of dry fertilizers over acres and acres. You might wind up with a cup of granules being added in to 25 sq ft. of soil for example. It is easier to figure out a smaller area for 1 plant then multiply by how many plants and there should be instructions for coverage on the fertilizer.

 

[puppasmurf]

so you are mixing something in a cubic meter container maybe?, sounds to me like blood n bone are granule fertilizers not liquids. I think you are figuring out how to spread lots of dry fertilizers over acres and acres. You might wind up with a cup of granules being added in to 25 sq ft. of soil for example. It is easier to figure out a smaller area for 1 plant then multiply by how many plants and there should be instructions for coverage on the fertilizer.

Yes it's not liquid all the fertz are granulars, unless solubles are used. I know how to broadacre fertilize but when using such little amounts on say 10 litres bags it confuses me easily. None of the fertilizers have application rates just chemical analysis which is the way I determine amounts. This in conjunction with knowing what the plant requires.

These little containers and amounts is "headbanging" My plan is to get enough soil for what i need, which might be 1/4 cubic metre (250 litres) then work out what to add within that range. The calculations is where im stuck as you know.

 

[SpicySativa]

Alright... I can definitely help you with the math (I am an engineer), but first I gotta understand what your goal is... Do you have a target of X kg of N per cubic foot of soil, or are you just trying to follow the label directions (which are listed in kg/HA)? In your first post you say the BnB is 8% N, you are after "85 N". What don you mean by this?

If you could list clearly what you know (what the package says) and what you want to know, I can help you crunch the numbers. I think you are straying from your goal when you start getting into HA*m (10,000 m^3). This would be assuming that the package directions call for tilling the material into the top meter of soil. In reality, it might be better to use something like acre*ft. A 1-ft tillage depth is a much better assumption.

 

[SpicySativa]

Let me try to simplify what I wrote while I was half asleep getting ready for work this morning...

In order to go from a package label or recommendation from a soil lab given in a "mass per area" to a container garden number in "mass per volume", you have to assume (or ask) what depth of soil that package label or lab recommendation is based on. By assuming a tillage depth (say...1 ft), you can then convert the package label directions to units of "mass per volume".

When you started using the hectare*meter number, you were essentially assuming an entire 1 meter depth of soil was being amended. Most farmed veggie crops are shallow rooted, so I would assume that package (and lab) recommended application rates are based on amending the top 1 ft or so of soil. Additionally, soil labs recommend collecting soil samples from just below the surface down to about 1 ft. From that you can assume this is the same interval of soil they base their recommendations on.

Make sense?

 

[SpicySativa]

Really though, I think you are making this WAY more complicated than it needs to be. Many of us here have years of experience mixing soils for cannabis, and we'd be happy to recommend mixing rates that have worked for us in the past.

Just as a little FYI, the application rates I use VERY RARELY match the recommendations on the label.

 

[puppasmurf]

Alright... I can definitely help you with the math (I am an engineer), but first I gotta understand what your goal is... Do you have a target of X kg of N per cubic foot of soil, or are you just trying to follow the label directions (which are listed in kg/HA)? In your first post you say the BnB is 8% N, you are after "85 N". What don you mean by this?

If you could list clearly what you know (what the package says) and what you want to know, I can help you crunch the numbers. I think you are straying from your goal when you start getting into HA*m (10,000 m^3). This would be assuming that the package directions call for tilling the material into the top meter of soil. In reality, it might be better to use something like acre*ft. A 1-ft tillage depth is a much better assumption.

85 N was the amount of nitrogen i use for my basal application for my garlic crop. I was using this with my equation as an example, its not relevant to cannabis.

Let me try to simplify what I wrote while I was half asleep getting ready for work this morning...

In order to go from a package label or recommendation from a soil lab given in a "mass per area" to a container garden number in "mass per volume", you have to assume (or ask) what depth of soil that package label or lab recommendation is based on. By assuming a tillage depth (say...1 ft), you can then convert the package label directions to units of "mass per volume".

When you started using the hectare*meter number, you were essentially assuming an entire 1 meter depth of soil was being amended. Most farmed veggie crops are shallow rooted, so I would assume that package (and lab) recommended application rates are based on amending the top 1 ft or so of soil. Additionally, soil labs recommend collecting soil samples from just below the surface down to about 1 ft. From that you can assume this is the same interval of soil they base their recommendations on.

Make sense?

I understand, about soil samples and fert application of root depth of plants. The package of BnB reads: N 8.0%, P 4.6%, K 0.5%. And at the bottom it does read 50-100 Grams per SqM. I can math that out well to a Ha but to volume I'm lost. Another problem is, in Oz land we don't have the products and the variety. There isn't much I can copy from here as most recipes are American product based. I was thinking 10 Gallon Geopots. So I was thinking of mixing up a soil batch of 300 Litres. So the Grams per square metre into 300 litres? That's where i'm lost.

Really though, I think you are making this WAY more complicated than it needs to be. Many of us here have years of experience mixing soils for cannabis, and we'd be happy to recommend mixing rates that have worked for us in the past.

Just as a little FYI, the application rates I use VERY RARELY match the recommendations on the label.

I can't help but make this complicated as I did a horticulture course and agronomy was my favourite unit. Knowing what elements play what role and knowing how much each element is vital I can't help but want the right dosage. I know this will come in time so I will take this more in a newbies perspective.

 

[SpicySativa]

You simply cannot go from "mass per surface area" to "mass per volume" without assuming a depth. That's just how math works.

Take a look at the document linked below, especially "Table 6". You'll see that in order to go from the recommended rates in "pound per acre" to their desired "teaspoon per 5 gallons", they had to assume a rooting depth (in this case 8").

http://aces.nmsu.edu/pubs/_h/h-119.pdf

I'll make your life easy... Assuming an 8" (0.2 meter) rooting depth...

1 m^2 * 0.2 m = 0.2 m^3, or 200 liters. At the low end recommended rate of 50 grams per m^2, this equals out to 50 grams per 200 liters, or 0.25 grams per liter. At the high end of the recommendation, this would be 0.5 grams per liter.

That make sense?

 

[SpicySativa]

Also, I mentioned this before, but the "right" dosage for indoor cannabis usually isn't the one listed on the package. That's where the years of experience come in.

Package directions say 0.25 to 0.5 grams per liter, which equates to about 0.05 tablespoons per liter at the high end (blood meal is about 0.62 grams per cubic centimeter). My experience tells me you want more like 1 TBSP/gal blood (if you choose it as your N source) and 1 TBSP bone (or 2 TBSP/gal blood and bone). This equals out to about 0.5 tablespoons per liter, about 10 times what the label recommends.

 

[puppasmurf]

You simply cannot go from "mass per surface area" to "mass per volume" without assuming a depth. That's just how math works.

Take a look at the document linked below, especially "Table 6". You'll see that in order to go from the recommended rates in "pound per acre" to their desired "teaspoon per 5 gallons", they had to assume a rooting depth (in this case 8").

http://aces.nmsu.edu/pubs/_h/h-119.pdf

I'll make your life easy... Assuming an 8" (0.2 meter) rooting depth...

1 m^2 * 0.2 m = 0.2 m^3, or 200 liters. At the low end recommended rate of 50 grams per m^2, this equals out to 50 grams per 200 liters, or 0.25 grams per liter. At the high end of the recommendation, this would be 0.5 grams per liter.

That make sense?

Thank you very much for your patience especially!

Even if I don't understand all of it straight away i'll read it until I do. Thanks again.

P.s Looking at your Org grow threads and your vortex brewer, just amazing and inspiring thanks again.

 

[SpicySativa]

No prob, man. Glad to help!