
Van Iperen Potassium Sulphate (SOP) Horticultural Grade is a highly pure Potassium fertilizer, free of Nitrogen, which dissolves rapidly and completely. Our product is not sensitive to caking and is recommended during fruit or tuber development, especially during periods of drought. The high level of Potassium in our formula improves the cell pressure and regulates the functioning of stomata. Furthermore, the absence of Nitrogen combined with the presence of Sulphur support generative growth.
- Improves fruit quality, shelflife and increases plant drought resistance
- Limits vegetative growth as of fruit setting
- Easy to handle, dissolve and apply
- Developed for fertigation in open field and greenhouses. Also suitable for foliar application

- Low on heavy metals
- Low on Sodium and Chloride
Hydroponics
Kg in 1.000 l stock solution | K2O in kg | SO3 in kg1 |
---|---|---|
25 | 12.7 | 11.2 |
50 | 25.5 | 22.5 |
75 | 38.2 | 33.7 |
100 | 51 | 45 |
Mentioned concentrations represents the amount of nutrients in the stock solution. The final concentration in the irrigation water depends on the amount of nutrients in the stock solution, the injection ratio and the amount of nutrients used in the water.
Fertigation
Crop | Application date | Min kg/ha/season | Max kg/ha/season |
---|---|---|---|
Fruit trees![]() |
• As of fruit setting • Until 4 weeks before harvesting |
150 | 350 |
Banana![]() |
• As of plant establishment • During entire fertigation program |
300 | 500 |
Citrus (adult)![]() |
• As of fruit setting • Until 4 weeks before harvesting |
200 | 400 |
Potato![]() |
• As of tuber setting • Until tuber filling |
100 | 200 |
Vineyards (adult)![]() |
• As of flower bud opening • Until 4 weeks before harvesting |
100 | 250 |
Pistachio![]() |
• As of vegetative growth • Until fruit filling |
170 | 300 |
Fruit bearing vegetables![]() |
• As of vegetative growth • Until 4 weeks before harvesting |
100 | 300 |
Asparagus![]() |
• During entire fertigation program | 200 | 300 |
Foliar Application
Crop | Application date | Min kg / ha / appl | Max kg / ha / appl | Conc. % (w/v)) |
---|---|---|---|---|
Fruit trees![]() |
3 - 5 applications: • As of fruit setting • 14 - 21 days interval |
7 | 10 | 1.0 - 2.0 |
Citrus ![]() |
3 - 5 applications: • As of fruit setting • 14 - 21 days interval |
9 | 12 | 2.0 - 3.0 |
Olive![]() |
3 - 5 applications: • As of fruit setting • 14 - 21 days interval |
9 | 12 | 2.0 - 3.0 |
Potato![]() |
3 applications: • As of 3 weeks after planting • 10 - 14 days interval |
4 | 6 | 1.0 - 3.0 |
Leafy crops![]() |
3 applications: • As of 4 weeks after planting • Until vegetative growth • 10 - 14 days interval |
5 | 8 | 0.5 - 1.0 |
Sugarbeet![]() |
2 - 3 applications: • As of second half of the season • 7 - 10 days interval |
5 | 8 | 2.0 - 3.0 |
Table grape![]() |
3 - 5 applications: • As of fruit setting • 14 - 21 days interval |
7 | 10 | 1.5 - 2.0 |
Fruit bearing vegetables![]() |
1 - 3 applications: • During vegetative growth • As of fruit setting • 10 - 14 days interval |
5 | 8 | 0.5 - 1.0 |
Carrots![]() |
3 applications: • As of 4 weeks after seeding • 10 - 14 days interval |
3 | 5 | 1.5 - 2.5 |
Onion![]() |
3 applications: • As of 4 weeks after seeding • 10 - 14 days interval |
5 | 8 | 2.0 - 3.0 |
Rapeseed![]() |
1 - 2 applications: • As of vegetative growth • Until beginning of flowering |
3 | 6 | 1.0 - 1.5 |
In case of foliar feeding as part of a mix with crop protection products, a compatibility test has to be done prior to preparing the spray-mix.
The mentioned indicated dosages and application stages are given as a guideline. Exact dosages, concentration and application stage are subject to local conditions, use of other fertilizers and can only be given after an objective diagnosis.
Compatible with other fertilizers, with the exception of Calcium fertilizers. Therefore a separate tank is needed or fertilizers should be applied on different times.