TWO FIELD experiments were carried out at the Experimental Farm of Sakha Agricultural Research Station, Egypt, during the two winter seasons of 201415/ and 201516/. The experiments were conducted to find out the suitable transplanting date(15^th December, 1^st January and 15^th January), the best planting method (ridges and wide furrows) and to assess three plant densities i.e.,30, 45 and 60 plants/m² for vegetative growth, yield and quality of onion under North Delta conditions. The main results showed that, the vegetative growth behavior was improved, also yield and its components and quality of onion were increased by transplanting onions on 15^th Dec. date in both seasons. Wide furrows planting method resulted in a significant increase in the most of vegetative growth characteristics, as well as total bulb yield and its components and bulb quality. Increasing plant density up to 45 plants/m² significantly increased most vegetative growth characteristics, total and marketable bulbs yield/fad and bulb qualityin 2014 /15 and 2015 /16 seasons.
Transplanting onions on 15ᵗʰ Dec. in wide furrows planting system significantly recorded the tallest plants, leaf area/plant, total bulbs yield, marketable bulbs yield and average bulb weight.Onion cultivar transplanted at 15ᵗʰ Dec. with 30 plants/ m2 resulted in a markedly increase in plant height, plant fresh and dry weight and leaf area/plant at the three sampling dates in both seasons. While, total and marketable bulbs yield/fad, was increased by transplanted at 15ᵗʰ Dec.with 45 plants/ m².The highest vegetative growth, total bulbs yield and bulb quality resulted from onions when were planted with 45 plants/m² in wide furrows planting method.
The economic evaluation showed that the highestgross and net return per fad and net benefit-cost ratio obtained from transplanting onions at 15^th Dec.(early date), wide furrows planting method with planting 45plants/ m². So, this study recommended onion farmers at North Delta of Egypt to transplanting onions at 15^th Dec. (early date) in wide furrows planting method with the plant density of 45 plants/m² to achieve the highest economic yield.