A field experiment comprising of six treatments, i.e., T1: N100 +1 row cowpea, T2: N100 + heramin, T3: N100 + 1 row cowpea + heramin, T4: N125, T5: N125 + 1 row of cowpea and T6: N125 + 1 row of cowpea + heramin, was conducted at Research Farm of the Department of Agriculture, Maharishi Markandeshwar University, Mullana-Ambala, Haryana during Rabi season of 2022-23 to find out the effect of cowpea green manure and biostimulant heramin on growth, grain yield and quality of maize. The treatments, which were laid out in a Randomized Block Design (RBD), were replicated thrice. The variety of maize used for the experiment was HQPM4. The maize plants (160.81 cm) were registered tallest with treatment T6 where nitrogen was applied @ 125 kg/ha along with one row of cowpea and heramin spray. Dry matter accumulation (391g), grain yield (6650 kg/ha), Stover yield (6120 kg/ha), biological yield (12770 kg/ha), harvest index (52.08 %) and net return (₹ 120410) were recorded maximum under the same treatment, which was at par with T3: N100 + 1 row cowpea + heramin spray in respect of plant height (160.54 cm), dry matter accumulation (390 g), grain yield (5400 kg/ha), Stover yield (5280 kg/ha), biological yield (10680 kg/ha), harvest index (50.56%) and net return (₹ 88200). Cowpea helped in the fixation of atmospheric nitrogen into the soil, which helped in increasing growth of maize and heramin reduced the need of fertilizer and increased growth of the maize plants.