EFFECT OF DIFFERENT PLANTING DATES AND SOME NATURAL EXTRACTS ON THE QUALITY OF GLADIOLUS GROWTH, FLOWERING AND CORMS PRODUCTIVITY

A pot experiment was performed in the open field of Ornamental Plants and Landscape Gardening Research Department Nursery, Horticulture Research Institute, Agricultural Research Center, Giza, Egypt, during 2019/2020 and 2020/2021 seasons to improve the quality of Gladiolus grandiflorus ‘Peters Pears’ growth and flowering. To achieve this goal different planting dates (July, October and February) and various soil drench additions (yeast and garlic extracts) were employed, while different parameters i.e. plant height (cm), leaf number/plant, spike stem length (cm), spike fresh and dry weights (g), corms fresh and dry weights (g), and pigments content of the fresh leaves (chlorophyll a, b and carotenoids; mg/g f.w.) were measured. The obtained results showed that planting on 15th October in addition to soil drenching with yeast extract produced the highest values in most studied characters except for corms' fresh and dry weights (g) which were increased by planting on 15th February in addition to soil drenching with yeast extract. So, to obtain the best results it is recommended to plant Gladiolus grandiflorus ‘Peters Pears’ corms on 15th October in addition to soil drenching with yeast extract (2 g/l three times at 15-day intervals)