Basic calculations to make your own hydroponics nutrients

Reference Rates for leafy greens:

Howard Resh

Observed

Rates

Cornell UA CEAC
N 165-200 125-200 210 189
P 50 15-90 31 39
K 150-210 80-350 235 341
Ca 150-200 38-220 200 170
Mg 40-60 14-96 49 48
S 64
Fe 5 1-10 4 2
Mn 0.5 0.25-1 0.5 0.55
Zn 0.05-0.15 0.1-2.5 0.1 0.33
B 0.3-0.5 0.14-1.5 0.5 0.28
Cu 0.03-0.15 0.023-0.13 0.1 0.05
Mo 0.02-0.05 0.024-0.075 0.01 0.05

 

To convert P2O5 to P, multiply by 0.4364 

To convert P to P2O5, multiply by 2.2915 

To convert K2O to K, multiply by 0.8301 

To convert K to K2O, multiply by 1.2047

For Example,

Potassium sulphate (0-0-50) 

P in potassium sulphate : 50 * 0.8301 = 41.5%

Choice of fertilizers:

You can use any fertilizers of your choice like 19-19-19 or ammonium nitrate, or any other water-soluble fertilizers. I am using these because they are cheap and easy to get. Below values may change when you change the brand. 

Calcium Nitrate: Ca: 18.8%, N: 15.5% 

Potassium Nitrate: 13-0-45 (13% N, 37.3% K) 

Magnesium Sulphate: Mg:10%

Potassium Sulphate: 0-0-50 (41.5% P)

Monopotassium phosphate: 0-52-34 (22.7% P, 28.7% K) 

Fe EDTA 18%

Micronutrient Mix: As per label 

Desired PPM Quantity:

N: 200 ppm P: 50 ppm K: 300 ppm

Ca: 200 ppm Mg: 50 ppm Fe: 5 ppm

Mn: 0.8 ppm Cu: 0.07 ppm Zn: 0.1 ppm

B: 0.3 ppm Mo: 0.03 ppm

You can test your water source and alter the above values accordingly. 

Calculations to achieve desired PPM quantity with available choices: 

Ca: 200ppm

Wt. of Calcium nitrate = Required Ca / Available % in fertilizer

= 200 PPM / 18.8%

= 200 / (18.8/100)

= 200 / 0.188

= 1063.8 PPM

= 1000 mg (Approx.)

= 1 gm

Weight of Calcium Nitrate: 1 gm/L

Fertilizer salts provide two ions. Let us calculate the ppm (or mg/L) of nitrogen supplied using 1000mg of calcium nitrate in 1 L of water. This is calculated by multiplying the total mg/L of fertilizer salt used by the percent nitrogen. (15.5% N)

N in added Calcium Nitrate: 1000 * 0.155 = 155 PPM

Calcium nitrate provides 155ppm Out of 200ppm of N required.

N Remaining = 200 – 155 = 45ppm 

N: 45ppm

Wt. of Potassium Nitrate 13-0-45 = Required N / Available % in fertilizer

= 45 PPM / 13%

= 45 / 0.13

= 346.15 ppm

= 0.35 gm/L

Weight of Potassium Nitrate: 0.35 gm/L

K in added Potassium Nitrate: 346 * 0.373 = 129 PPM

Potassium Nitrate provides 129 ppm Out of 300ppm of K required.

K Remaining = 300 – 129 = 171ppm

P: 50ppm

Wt. of Monopotassium phosphate (0-52-34) = Required P / Available % in fertilizer

= 50 PPM / 22.7%

 = 50 / 0.227

= 220.26 ppm

= 0.22 gm/L

Weight of Monopotassium phosphate: 0.22 gm/L

K in added Monopotassium phosphate: 220 * 0.287 = 63.14 PPM 

Monopotassium phosphate provides 63 ppm Out of 300ppm of K required.

K Remaining = 171-63 = 108ppm 

K: 108ppm

Wt. of Potassium Sulphate (0-0-50) = Required K / Available % in fertilizer

= 108 PPM / 41.5%

= 108 / 0.415

= 260.2 ppm

= 0.26 gm/L

Weight of Potassium Sulphate: 0.26 gm/L 

Mg: 50ppm

Wt. of Magnesium Sulphate (10% Mg) = Required Mg / Available % in fertilizer

= 50 PPM / 10%

= 50 / 0.1

= 500 ppm

= 0.5 gm/L

Weight of Magnesium Sulphate: 0.5 gm/L

We will use a micronutrient mix to provide all micronutrients. We will use FeEDTA (13% iron) because the micronutrient mix contains Fe at low levels. Out of 5ppm required, Fe EDTA will provide 4ppm Fe.

Fe: 4pmm

Wt. of FeEDTA (13%) = Required Fe / Available % in fertilizer

= 4 PPM / 13%

= 4 / 0.13

= 30.7 ppm

= 0.03 gm/L

 Weight of FeEDTA: 0.03 gm/L

 

 1. Total Fertilizer Weights to make 1L of nutrients solution: 

Weight of Calcium Nitrate: 1 gm/L

Weight of Potassium Nitrate: 0.35 gm/L

Weight of Monopotassium phosphate: 0.22 gm/L

Weight of Potassium Sulphate: 0.26 gm/L

Weight of Magnesium Sulphate: 0.5 gm/L Weight of FeEDTA: 0.03 gm/L

Weight of Micronutrients: As per the label

 

  2. To make a volume of nutrients solution, multiply water volume to above weights. Total Fertilizer Weights to make 1000L of nutrients solution:

Weight of Calcium Nitrate: 1000 gm/L

Weight of Potassium Nitrate: 350 gm/L

Weight of Monopotassium phosphate: 220 gm/L

Weight of Potassium Sulphate: 260 gm/L

Weight of Magnesium Sulphate: 500 gm/L Weight of FeEDTA: 30 gm/L

Weight of Micronutrients: As per the label

 

3. To make stock solutions, check solubility of salts:

All salts are within soluble values.

We will put all nitrates in Stock A and phosphates and sulphates in Stock B.

To make 200x of stock solution for 10L Volume,

Stock A

Weight of Calcium Nitrate: 1 gm/L*200*10 = 2kg

Weight of Potassium Nitrate: 0.35 gm/L *200*10 = 700gm

Weight of FeEDTA: 0.03 gm/L * 200 * 10 = 60gm

Stock B

Weight of Monopotassium phosphate: 0.22 gm/L * 200 *10 = 440gm

Weight of Potassium Sulphate: 0.26 gm/L * 200 * 10 = 520gm

Weight of Magnesium Sulphate: 0.5 gm/L * 200 * 10 = 1kg

Weight of Micronutrients: As per the label * 200 * 10

 

 

Chemist Direct Online discount pharmacy Chemist Direct offers a massive selection of healthcare and beauty products including vitamins, supplements, medicines and personal care items. cialis malaysia pharmacy Adairs Bedding and homewares specialist Adairs offers a comprehensive collection of bed linen, bathroom accessories, plants and more.