Tulip bulb production is limited under drought stress conditions. Due to nutrient limitations, the growth rate is significantly reduced. Attention needs to be given to the plant-related microbiome because it can help the plant cope with stressful situations. A three-factor experiment (cultivar, SB fertilizer, and drought stress) was set up to study tulip bulb characteristics. Drought stress at three levels (90, 80, and 70% of field capacity, FC), SB fertilizer at four levels (control, PSB, KSB, and PSB+KSB), and two cultivars (‘Golden Melody’ and ‘Apeldoorn’) were applied. The application of PSB+KSB significantly increased the nutrient concentration (N, P, and K) in different parts of tulips, including the root, bulblet, outer and inner scale, under drought stress. The bulblet of ‘Golden Melody’ accumulated more K and P than ‘Apeldoorn’ under drought conditions. Water-soluble sugar accumulation was maximum to a minimum depending on the outer scale ˃ bulblet ˃ inner scale. Application of PSB and KSB with irrigation water reduced the adverse effects of drought stress on water-soluble sugars, anhe combined treatment of PSB+KSB resulted in the highest amount of water-soluble sugars in a tulip, indicating a synergistic effect of PSB and KSB on tulip bulbs. The highest leaf number and leaf area were observed at 90% FC when PSB+KSB was applied. Drought stress reduced the number, diameter, and weight of bulbs, while application of PSB+KSB resulted in the highest diameter (47.7 mm), and weight (45.3 g) of cultivar ‘Golden Melody’. Application of PSB+KSB fertilizer over irrigation water promoted bulb production of tulip cultivars under drought stress.

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