Wetherill
A History of Discovery
Hydroponic Greenhouse Production
Jim Shaffner was the Horticulturist for a world class
Hydroponic
Greenhouse growing facility, producing Hydroponically grown European
seedless cucumbers and hybrid tomatoes. The method used was a nutrient
rich solution applied through a drip system onto sand beds. The five acre greenhouse facility produced many
tons of vegetables per month which were shipped all over the United
States. Jim developed several new Hydroponics formulas for
vegetable crops and later developed several formulas which were used to
produce
floral crops for a large wholesale flower and foliage production
facility. The formulas developed for floral crops were
specific for various crops and were proven to deliver excellent results
with predictable outcomes from crop to crop.
Nutrient formulas and how to calculate the quantities for various applications is a straight forward operation. A grower should mix their own fertilizer combinations to prevent errors from others. Making Hydroponic fertilizers from raw materials is not rocket science and will assure a quality material that you yourself control.
There are several formulas for calculating the parts per million (ppm) required for elements in a nutrient solution. The most common method uses a fertilizer compound chart (Click here) as a starting point for the design of your nutrient solution. Lets assume you are raising a crop that requires 200 ppm potassium (K), 200 ppm nitrogen (N) and 62 ppm phosphorus (P). Let's use potassium nitrate (KNO3) as the sole source of potassium, a 95:1 concentrate injector and a 30 gallon stock solution tank. Use no more than a 100:1 injection rate as to much material drops out of solution with a higher than 100:1 rate.
Find potassium nitrate on the chart, select 97 under K. This number represents the ppm of potassium when 1 gram is dissolved in 1 gallon of water. Now divide 200 by 97. The answer is 2.06 which is the number of grams to dissolve in 1 gallon of water to obtain 200 ppm K. Now multiply 95 (Injection rate of 95:1) times 30 (30 gallon stock solution tank size) times the 2.06 (Grams per gallon) which equals 5876.2 grams or 12.9 pounds. here is the actual formula without the rhetoric. 200/97x30x95/453.6
Now lets calculate how much N is in potassium nitrate when 2.06g is dissolved in 1 gallon of water. Find potassium nitrate on the chart and select 36 under N. Multiply 30 times 2.06 which is 74.1 ppm N. Potassium nitrate provides 200 ppm K and 74.1 ppm N which leaves a balance of 125.9 ppm N which needs to be obtained from another source.
Checking the chart we find that that calcium nitrate Ca(NO3)2 will provide nitrogen and calcium (Ca) so would be an excellent choice. The calculation would be as follows. Find calcium nitrate on the chart, select 41 under N and divide 125.9 by 41 which equals 3.07 g. Multiply the grams times the proportion rate, times the stock solution tank size and divide by 453.6 (Number of grams in a pound). The answer is 19.2 pounds. The calcium nitrate also provides calcium at 153.5 ppm.
with predictable outcomes from crop to crop. Nutrient formulas and how to calculate the quantities for various applications is a straight forward operation. A grower should mix their own fertilizer combinations to prevent errors from others. Making Hydroponic fertilizers from raw materials is not rocket science and will assure a quality material that you yourself control.
There are several formulas for calculating the parts per million (ppm) required for elements in a nutrient solution. The most common method uses a fertilizer compound chart (Click here) as a starting point for the design of your nutrient solution. Lets assume you are raising a crop that requires 200 ppm potassium (K), 200 ppm nitrogen (N) and 62 ppm phosphorus (P). Let's use potassium nitrate (KNO3) as the sole source of potassium, a 95:1 concentrate injector and a 30 gallon stock solution tank. Use no more than a 100:1 injection rate as to much material drops out of solution with a higher than 100:1 rate.
Find potassium nitrate on the chart, select 97 under K. This number represents the ppm of potassium when 1 gram is dissolved in 1 gallon of water. Now divide 200 by 97. The answer is 2.06 which is the number of grams to dissolve in 1 gallon of water to obtain 200 ppm K. Now multiply 95 (Injection rate of 95:1) times 30 (30 gallon stock solution tank size) times the 2.06 (Grams per gallon) which equals 5876.2 grams or 12.9 pounds. here is the actual formula without the rhetoric. 200/97x30x95/453.6
Now lets calculate how much N is in potassium nitrate when 2.06g is dissolved in 1 gallon of water. Find potassium nitrate on the chart and select 36 under N. Multiply 30 times 2.06 which is 74.1 ppm N. Potassium nitrate provides 200 ppm K and 74.1 ppm N which leaves a balance of 125.9 ppm N which needs to be obtained from another source.
Checking the chart we find that that calcium nitrate Ca(NO3)2 will provide nitrogen and calcium (Ca) so would be an excellent choice. The calculation would be as follows. Find calcium nitrate on the chart, select 41 under N and divide 125.9 by 41 which equals 3.07 g. Multiply the grams times the proportion rate, times the stock solution tank size and divide by 453.6 (Number of grams in a pound). The answer is 19.2 pounds. The calcium nitrate also provides calcium at 153.5 ppm.
Greenhouse cucumbers
These plants are grown in sand beds with a hydroponic nutrient solution applied at every irrigation.
Tomato plants growing in hydroponic sand beds.