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A Hydroponic Fertilizer Formula
Since on the other forums here there has been a lot of talk about growing crypts and other plants emersed, and some of us are trying hydroponics, I found the following recipe which I have tried to duplicate.
MgSo47H20 50 ppm Mg
KH2PO4 77 ppm K, 62 ppm P
KNO3 77 ppm K, 28 ppm N
K2SO4 45 ppm K
Ca(NO3)2 85 ppm N, 122 ppm Ca
Fe 2.5 ppm Fe
This comes out to:
50 ppm Mg
199 ppm K
113 ppm N
62 ppm P
2.5 ppm Fe
122 ppm Ca,
which is what I am shooting for.
I first tried starting with KNO3 but when you get the N right the K is far too much. Also HeyPK has said Ca(NO3)2 is hard to get and use, so using KNO3 was not a good idea if you want to keep the K down.
So I tried Miracle-Gro as a base, which is:
15% N
30% P2O3 (16.9% P)
15% K2O (12.4% K)
.15% Fe
So I have figured that 367mg/liter of Miracle-Gro gives you:
55 ppm N
62 ppm P
45 ppm K
.6 ppm Fe
The P is fine, but the rest of the elements are low. We need an additional 58 ppm N, 154 ppm K, and 1.9 ppm Fe. 414 mg KNO3 gives us the needed 58 ppm N and also 161 ppm K. To get the Fe we need to add CSM+B which is 6.53% Fe. 29.1 mg/liter of CSM+B gives us the needed additional 1.9 ppm Fe. In addition we need 50 ppm Mg. 538 mg of Epsom salts will give us that.
So
367mg/liter Miracle-Gro
414 mg/liter KNO3
29.1 mg/liter of CSM+B
538 mg/liter of Epsom salts
gives you:
50 ppm Mg
204 ppm K
113 ppm N
62 ppm P
2.5 ppm Fe
This is very close to the original recipe! My water has 48 ppm Ca and while the formula recommends 122 ppm, I will wait until I find an easy way to add calcium. I like to store my solution at 10X concentration in 3 liter bottles because they fit on the refrigerator door. Therefore, to make a 10X solution in 3 liters of water use:
11.0 grams of Miracle-Gro
12.4 grams of KNO3
.9 grams of CSM+B
16.1 grams of Epsom salts
Regards,
Steve P.
Since on the other forums here there has been a lot of talk about growing crypts and other plants emersed, and some of us are trying hydroponics, I found the following recipe which I have tried to duplicate.
MgSo47H20 50 ppm Mg
KH2PO4 77 ppm K, 62 ppm P
KNO3 77 ppm K, 28 ppm N
K2SO4 45 ppm K
Ca(NO3)2 85 ppm N, 122 ppm Ca
Fe 2.5 ppm Fe
This comes out to:
50 ppm Mg
199 ppm K
113 ppm N
62 ppm P
2.5 ppm Fe
122 ppm Ca,
which is what I am shooting for.
I first tried starting with KNO3 but when you get the N right the K is far too much. Also HeyPK has said Ca(NO3)2 is hard to get and use, so using KNO3 was not a good idea if you want to keep the K down.
So I tried Miracle-Gro as a base, which is:
15% N
30% P2O3 (16.9% P)
15% K2O (12.4% K)
.15% Fe
So I have figured that 367mg/liter of Miracle-Gro gives you:
55 ppm N
62 ppm P
45 ppm K
.6 ppm Fe
The P is fine, but the rest of the elements are low. We need an additional 58 ppm N, 154 ppm K, and 1.9 ppm Fe. 414 mg KNO3 gives us the needed 58 ppm N and also 161 ppm K. To get the Fe we need to add CSM+B which is 6.53% Fe. 29.1 mg/liter of CSM+B gives us the needed additional 1.9 ppm Fe. In addition we need 50 ppm Mg. 538 mg of Epsom salts will give us that.
So
367mg/liter Miracle-Gro
414 mg/liter KNO3
29.1 mg/liter of CSM+B
538 mg/liter of Epsom salts
gives you:
50 ppm Mg
204 ppm K
113 ppm N
62 ppm P
2.5 ppm Fe
This is very close to the original recipe! My water has 48 ppm Ca and while the formula recommends 122 ppm, I will wait until I find an easy way to add calcium. I like to store my solution at 10X concentration in 3 liter bottles because they fit on the refrigerator door. Therefore, to make a 10X solution in 3 liters of water use:
11.0 grams of Miracle-Gro
12.4 grams of KNO3
.9 grams of CSM+B
16.1 grams of Epsom salts
Regards,
Steve P.