Nutrient preparations
Because of the tendency of some nutrients to combine with others and
precipitate when concentrated the standard procedure is to prepare two
solutions where precipitating components are kept separate. When a
prepared solution is added to the nutrient water the concentrations are so
low that precipitation does not cause any problems. Calcium phosphate and
calcium sulphate are the main concern. Calcium is therefore kept away from
phosphate and sulphate in the formulations. Never add both nutrients
solutions together and then add into the water feed - valuable nutrients
will precipitate and become unavailable.
Ideal water temperature for total solubility of the nutrient salts is
20 to 22 OC.
Example...
 | Note: Plants have varying requirement between species and growth
stages. |
Part A Solution
Using 100 litres of water add: |
Part B Solution
Using 100 litres of water add: |
| Calcium Nitrate |
7.5 kg |
Potassium Nitrate |
9.0 kg |
| |
|
Potassium di-hydrogen phosphate |
3.0 kg |
| |
|
Magnesium sulphate |
6.0 kg |
| |
|
Iron Chelate EDTA |
300g |
| |
|
Manganese sulphate |
40g |
| |
|
Borax |
37g |
| |
|
Copper sulphate |
8g |
| |
|
Zinc sulphate |
4g |
| |
|
Ammonium molybdate |
1g |
| Solutions are 100 times more
concentrated than required for plants. Dilute to 1 in 100. |
pH affects nutrient availability.
| pH values above 7.5 cause iron, manganese, copper, zinc and boron
ions to be less available to plants. |
| pH values below 6 cause the solubility of phosphoric acid, calcium
and magnesium to drop. |
| pH values between 3 and 5 and temperatures above 26 OC encourage the development of fungal diseases. |
Copyright © 1996, 1997, 2001 TPS Pty Ltd
|
