DILTA, B.S.GUPTA, JAGREETI2016-12-202016-12-20201348075http://krishikosh.egranth.ac.in/handle/1/91359ABSTRACT The present investigations entitled, “Effect of growing substrates and pot sizes on growth and flowering of Primula malacoides Franch.” were carried out at experimental farm of Department of Floriculture and Landscaping, Dr. Y. S. Parmar University of Horticulture and Forestry, Nauni, Solan (H.P) during September, 2012- April, 2013 to work out the most suitable growing substrate and pot size for producing the best quality and most presentable potted Primulas. The experiment was laid out in Completely Randomized Design (factorial) having 21 treatment combinations of growing substrates and pot sizes replicated thrice with five pots per treatment. Seven growing substrates viz., Soil: FYM: Sand (1:1:1, v/v), Ban Oak (Quercus semicarpofolia) leafmould : FYM : soil (2:1:1, v/v), Rhododendron (Rhododendron arboreum L.) leafmould : FYM : soil (2:1:1, v/v), Rai (Picea smithiana L.): FYM : soil (2:1:1, v/v), Chirpine (Pinus roxburghii L.) leafmould : FYM: soil (1:1:1, v/v), Cocopeat : FYM : sand (1:1:1, v/v), Spent mushroom compost : FYM: sand (2:1:1, v/v) and three pot sizes i.e. 15, 20, 25 cm diameter pots, respectively. The observations were recorded on plant height (cm), number of branches or shoots per plant, shoot length (cm), plant spread (cm), days to flower bud formation (days), days to first flower opening (days), length of inflorescence stalk (cm), inflorescence diameter (cm), number of inflorescences per plant, number of flowers per inflorescence, number of flowers per plant, duration of flowering (days) and pot presentability score at the time of peak flowering. The growing substrate comprising cocopeat: FYM: sand (1:1:1, v/v) recorded maximum values in terms of plant height (43.05 cm), number of shoots or branches per plant (36.37), shoot length (25.38 cm), plant spread (36.58 cm), length of inflorescence stalk (17.43 cm), inflorescence diameter (5.89 cm), number of inflorescences per plant (37.54), number of flowers per inflorescence (18.28), number of flowers per plant (707.20) highest pot presentability score (84.22), minimum days to flower bud formation (104.10 days ) as well as days to first flower opening (106.80 days). As regards the effects of pot sizes, 25 cm diameter pots exhibited, maximum plant height (37.20 cm), number of branches or shoots per plant (35.16), shoot length (23.18 cm), plant spread ( 39.50 cm), days to flower bud formation (108.10 days), days to first flower opening (111.70 days), length of inflorescence stalk (16.78 cm), inflorescence diameter (5.89 cm), number of inflorescences per plant (34.65), number of flowers per inflorescence (20.13), number of flowers per plant (703.10), duration of flowering (99.60 days) and pot presentability score (81.67). The study indicated that most desirable and presentable potted plants of primula can be raised in 25 cm diameter pots by using cocopeat : FYM : sand (1:1:1, v/v) growing substrate.enThesis