ÖZETBu araştırma farklı fide yaşının Erzurum koşullarında yetiştirilenlahanada bitki gelişmesine ve verime etkilerim tesbit etmek için yürütülmüştür.Araştırma sonunda elde edilen sonuçlar şu şekilde Özetlenebilir; (1) pazarlanabilir en yüksek ürün i. yaş grubunda meydana gelmiştir; (.2) baş tutma oranı, ortalama baş ağırlığı, baş çapı ve baş yüksekliği I. yaş grubu lahanalarda; gövde uzunluğu ve açık yaprak ağırlığı ise III. yaş grubu lahanalarda en fazla olmuştur.THE EFFECT OF PLANT AGE ON GROWTH AND YIELD OF CABBAGE(Brassica oleracea var. Capitata L., IN ERZURUM CONDİTİONSSUMMARYThis study was carried out to deterrrdne the effect of plant age on plant growth and yield in Erzurum conditions. Plants were grown at the Agricultural Experiment Station No 6 in Erzurum, Turkey. Cabbage cultivar, named Zöhrap locally, was grown widely thefıeld conditions.For three different plant ages, the seed sown April 1, April II, and April 21. At the end of the harvest total yield, percent of heading, diameter and height of heads; height ofstems number and weight of open leaves were determined.The following results were obtained:1- The yield, head weight, head diameter, head height and percent of heading increasedwith increases in the seedlings age.2- The height of stem and the weight of open leaves were greatest in the youngest transplants.3- The lowest open leaves obtained by youngest seedlings.