<p>The aim of this study was to examine the effect of different fertilizers on the yield and antioxidant capacity of two lettuce genotypes &ldquo;Santoro RZ&rdquo; and &ldquo;Kiribati RZ&rdquo;.</p>
<p>Lettuce genotypes are fertilized with organic fertilizer (Slavol) and organic-inorganic NPK fertilizer (Fitofert hemisuper plus ) during the vegetation. The analyzed parameters were root length and head weight of lettuce, total phenols, and flavonoids, as well as antioxidant capacity. Lettuce genotypes &ldquo;Santoro RZ&rdquo; and &ldquo;Kiribati RZ&rdquo; fertilized with organic fertilization showed the highest content of total phenols (358.13 &plusmn; 1.30 mg RU/100 g of fresh sample), the total content of flavonoids (114.22 &plusmn; 0.3 mg RE/100 g of fresh sample) and antioxidant capacity (neutralization of DPHH radicals 58.72 &plusmn; 1.88%).</p>
<p>The results revealed that the yield and antioxidant capacity of lettuce can be improved by using organic fertilizers.</p>