Apples grow on temperate climates and their buds need cold periods to open. During winter the plant can withstand temperatures down to -10 °C, but once it blooms flowers cannot tolerate frost. Optimal soil pH for an apple plantation is between 6.0 and 6.5. Where soil and subsoil are naturally acid, it is recommended that they are slightly limed prior to planting. Good soil drainage is of primary importance, due to obligatory aeration of the tree's roots. Apple requires a large amount of potassium, since it is removed by the fruit at a 3-fold higher rate than nitrogen. Best apple mineral nutrition regime includes the use of fertigation with fully-soluble fertilizers and foliar feeding.