Sunflower performs best in rich soils (preferably containing more than 130 ppm of K2 O and 15 ppm of P2 O5 ), loamy or sandy/loamy or deep ones. Sunflower is a medium salt tolerant crop, enjoying a pH range of 6.5 – 7.5. Sunflower is not ideally growing in pure sandy soils, compacted or cold heavy ones.
Temperature and density
Minimum temperature for germination: 4-5˚C, but optimum is 7-8 ˚C expecting the emergence within 14 days. From emergence till inflorescence, sunflower performs best at 15 - 17 ˚C. Optimum average day temperature at grain filling is 20 - 22 ˚C. Temperature above 30 ˚C will lead to reduction of pollen viability and therefore to increased percentage of dried seeds, reducing the quantity of the oil and its content of the linoleic acid, and the final yield.