Nitrogen, phosphorus, and potassium fertility management in soilless growth media for potted geranium and petunia

Greenhouse production is increasing, and resource efficiency and sustainability are becoming more important. Therefore, while producing potted plants using soilless medium, it is essential to add fertilizer at the proper rates to maximize plant development and productivity. For geranium ‘Maverick Red’ and petunia ‘Dreams Pink’, treatments included (0–0–0), (0–200–200), (200–0–200), (200–200–0), (100–200–200), (200–100–200), (200–200–100), (200–200–200), (300–200–200), (200–300–200), (200–200–300), (400–200–200), (200–400–200), and (200–200–400) mg L −1 of nitrogen (N), phosphorus (P), and potassium (K), respectively. Soilless media analysis, leaf nutritional analysis, shoot fresh weight, shoot dry weight, root dry weight, leaf number, and chlorophyll concentration were recorded. Treatment 400–200–200 mg L−1 treatment for geranium had the greatest total number of umbels, plant width, and plant height. Petunia plants grown with 200 Nmg L−1 with any rate of P and K had the greatest number of flowers plant width, and plant height. Balanced fertilization of 200–200–200 mg L−1 optimized growth and flowering in petunia, while geranium benefited from greater N 300–200–200 mg L−1 to support vegetative vigor without delaying bloom.