大蔥(cong)(cong)對土壤(rang)(rang)(rang)(rang)適應性強(qiang)，無論是沙壤(rang)(rang)(rang)(rang)土還(huan)是粘(zhan)(zhan)(zhan)壤(rang)(rang)(rang)(rang)土都可栽(zai)培。由于沙壤(rang)(rang)(rang)(rang)土有機質(zhi)含量少，而且保水保肥力差，所以(yi)在沙壤(rang)(rang)(rang)(rang)土上種(zhong)植(zhi)(zhi)大蔥(cong)(cong)，蔥(cong)(cong)白粗糙松(song)弛，外干膜層(ceng)數多，不(bu)脆嫩，辛辣(la)味重，不(bu)耐貯運。粘(zhan)(zhan)(zhan)壤(rang)(rang)(rang)(rang)土上種(zhong)植(zhi)(zhi)的大蔥(cong)(cong)，雖然組織致(zhi)密結實，蔥(cong)(cong)白潔白細(xi)長，但因土壤(rang)(rang)(rang)(rang)通氣(qi)性差，不(bu)利于根系發育，植(zhi)(zhi)株纖弱，蔥(cong)(cong)白細(xi)長，產量低。實踐證明，大蔥(cong)(cong)要(yao)獲(huo)得(de)優質(zhi)高(gao)產，需選擇(ze)土層(ceng)質(zhi)地疏松(song)、呈粒狀的深褐色粘(zhan)(zhan)(zhan)質(zhi)壤(rang)(rang)(rang)(rang)土，而且要(yao)選擇(ze)土壤(rang)(rang)(rang)(rang)耕作層(ceng)深厚、有機質(zhi)豐富、肥水保持(chi)力強(qiang)的地塊種(zhong)植(zhi)(zhi)。