Liquid fert to percentage of medium weight?

[Hydro-Soil]

Ok.. excuse my brain fart here but... I can't seem to wrap my head around what equation I'm looking for.

I want .8% of my medium weight to be nitrogen. Using a liquid fert that's 5% nitrogen... how much do I need to apply to one pound of medium? Do I weigh the liquid? Measure the volume of the medium??


There are some things I don't do well... this is an example of one of them. lol

Thanks so much and...

Stay Safe!

 

[s00thsayer]

(x * .05) / 16 = .008 ... solve for x

x * .05 = .128

x = 2.56 ounces

 

[s00thsayer]

I don't know what you are looking for or what methods of fertilizing you are using but that number seems high. I would feed a 5% nitrogen liquid fertilizer at 1/3 tsp per gallon of water at every watering.

 

[Hydro-Soil]

It's ok... the question is theoretical to get an equation... just figured someone in the soil-growers forum would be up on this.

So... I should just go by weight? Trying to come up with the same answer as you, working backwards.

lb is 453.6'ish grams so 1% of that would be 4.54g... so approximately 4g of nitrogen would make up around .8% of 1lb of medium.....

Working with a source material that's only 5% pure...
4g=5%
8g=10%
80g=100%

So 80g??

You know... I remember having issues like this in chemistry class. LOL Appreciate the help, just don't 'get' it yet. LOL So sorry.

Glad I can laugh at the autistic traits I haven't been able to work around yet... life was really bad before that.

Stay Safe!

 

[s00thsayer]

Roughly...more like 72 grams.

x = the unknown amount you need to add
5% = 0.05
.8% = 0.008
1 pound = 16 ounces or 453.6 grams

In grams the formula would be...

(x * .05) / 453.6 = .008 ... solve for x

x * .05 = 3.6288

x = 72.576 grams

so...in 72.576 grams of fertilizer there would be a total of 3.6288 grams of nitrogen

double-checking.... 3.6288 grams of nitrogen divided by 453.6 grams of medium would yield 0.008....multiply that by 100 to convert to percentage and you get 0.8% nitrogen

 

[Hank Hemp]

I've never heard of adding ferts by weight of soil or the plant for that matter. Is this something new you've dug up?

 

[Hydro-Soil]

Nah... it's nothing to do with growing. LOL

The question was just theoretical so I could do something else with it.

THANKS SO MUCH!

Stay Safe!