In hydroponic crops production pH and E.C are critical concerns as they adversely affect crop growth, development which automatically compromise yields. This knowledge is much important to farmers who grow crops in open fields and also in protected environments using fertigation systems.
Requirements
- Phosphoric acid
- pH and E.C meter
- Pumice
- Hand gloves
- 40L of clean plain water
- 60L containers
Procedure
- Double rinse the pumice using clean plain water
- Take E.C and Ph readings
- Add 5ml phosphoric acid to 40L of clean water and stir using a rod
- Pour pumice into the phosphoric acid solution and stir thoroughly
- Take Ph, E.C and temperature readings
- Rinse pumice with clean water and mix proportionally with treated cocopeat
| CROP | ELECTRONIC CONDUCTIVITY |
| Lettuce-loose headed | 0.3-0.8 |
| Lettuce-compact headed | 0.6-1.4 |
| Tomato | 1.8-2.8 |
| Peppers | 1.8-2.8 |
| Spinach/collards | 1.8-3.5 |
| Straw berries | 1.8-2.5 |
| Asparagus | 1.4-1.8 |
| cabbage | 1.4-2.4 |
| Egg plant | 1.8-2.2 |
| Cauliflower | 1.4-2.4 |
| Maize | 1.6-2.4 |
| parsley | 0.8-1.8 |
| okra | 2.0-2.4 |
| pumpkin | 1.4-2.4 |
| cucumber | 1.6-2.4 |
| peas | 1.4-1.8 |
| beans | 1.8-2.5 |
NB:Phosphoric acid is highly corrosive, should be handled with a lot of care. Wear gloves when treating pumice, when stirring use a rod.
The above E.C table shows just few crops grown in Kenya, to get the other crops E.C values it’s just a matter of knowing the crop family. All crops within one family differ slightly in the E.C values basically due to differences in nutritional demands.