In quite hot climatic zones, as in Italy, the sowing happens in October–November, after having ploughed the soil to bury the stubble of the previous crop, often a cereal. 100–150 kg/ha of seeds are used to obtain a final plant population of 30 plants per square meter, in rows 30 cm distant to each other. Thanks to its branched structure, the lupin can adapt to different sowing densities, compensating for a lower density with a higher branch growth. In colder zones, where lupin can't get through the winter, white lupin is sowed in the springtime, between March and April. The soil must be prepared as soon as possible after the winter break. The seedbed must be enough fine, particularly in organic farming where mechanical weeding is done (so that by harrowing the displacement of clods doesn't cause harm). In case of mechanical weeding we wish a higher plant density (about 100 plants / m2), sowing about 200 kg seeds/ha, at a sowing depth of 3–4 cm. In the regions where lupin isn't indigenous, if it is cultivated for the first time on a soil or if the soil pH is higher than 6.5, lupin seeds must be inoculated with the nitrogen fixing bacterium "Rhizobium lupini". Soil acidity is an important factor for nitrogen fixation.