A field experiment was conducted during rabi season of the year 2014 and 2015 at Govind Ballabh Pant University of Agriculture and Technology, Pantnagar, (Uttarakhand) to assess the effect of sowing times (22nd October, 1st November and 11th November) and plating geometries on the thermal requirement of Indian mustard var. RGN-73. The crop sown on 22nd October was found superior for accumulation of all the thermal indices; and among the planting geometries, the wider geometries (30 × 30 cm, 45 × 15 cm and 45 × 30 cm) accumulated more thermal units. Seed yield was found highest in case of the 22nd October sown crop (1665.3 kg/ha) followed by 1st and 11th of November while the closer geometries 30 × 10 cm (1635.2 kg/ha) and 30 × 20 cm (1650.3 kg/ha) reported more grain and seed yields. The HUE was in accordance with the seed and biological yields; therefore it could be used as a measure to decide the most favorable time of sowing to get higher yields of Indian mustard. The October 22 sown crop exhibit better vegetative growth and final yield than that of others. Closer plant sapcing resulted into more vertical growth. Closer geometries exhibited maximum yield than on the spacing. Using closer geometries with a delay in sowing would result into better yields.

Keywords: Brassica Juncea; Sowing Dates; Planting Geometries; Vegetative Growth; Seed Yield.