Abstract Two separate field experiments were carried out on sweet pepper at the Experimental Farm of the Faculty of Agriculture, Moshtohor, Benha university, in clay loam soil during the summer seasons of 2004 and 2005 and during the winter seasons of 2005/2006 and 2006/2007. Study in the summer seasons aimed to investigate the effect of organic manure and/or mineral N‐fertilizer with or without Microbin as biofertilizer and foliar application with Delfan as amino acids, garlic extract or without foliar application on growth, yield and quality of plants. Results show that using 30 kg organic‐N + 30 kg mineral‐N/feddan combined with Microbin and spray with Delfan gave the best growth and increased early and total yield with the best fruit quality as compared with all other used treatments. The experiment in the winter seasons aimed to study the effect of treating swelling seeds at low temperature (‐1oC) for about 24 h before planting in order to improve cold tolerance of sweet pepper plants grown in the open field compared with planting under low plastic tunnels and foliar application with Delfan, micronutrients or sucrose alone or mixed foliar application with the three materials. Results show that plants grown under low plastic tunnels with mixed foliar application with chilling seeds under ‐1oC, gave the most favourable growth, the highest early and total yield per feddan with the best fruit quality of sweet pepper plants.