Yellow leaves are the most common worry in Indian home gardens, and the cause is usually one of four things. Look at WHERE the yellowing starts:
Old (lower) leaves first, whole leaf evenly yellow — usually nitrogen hunger. The plant is moving nutrients to new growth. A gentle monthly feed (vermicompost, or dilute NPK) fixes it; watch the new leaves, not the old.
Yellow between the veins, veins stay green — a mineral deficiency. On OLD leaves it's usually magnesium (a teaspoon of Epsom salt in a litre of water, sprayed weekly, works wonders). On NEW leaves it's usually iron — common in pots with hard tap water; a chelated micronutrient spray helps.
Yellowing with constantly wet soil — overwatering, the silent killer. Roots need air. Let the top few centimetres dry before watering again, and make sure the drainage hole is open. After heavy monsoon rain, yellow leaves on roses and other pot plants are extremely common — improve drainage and hold back fertilizer until you see new growth.
Yellowing with curled, sticky, or speckled leaves — look closer: insects. Check under leaves for mealybugs (white cotton), aphids (tiny green clusters) or the fine webbing of mites. Neem oil (3–5 ml per litre with a few drops of soap, sprayed in the evening) handles most of them.
Every Hindu household has a tulsi — and monsoon is when it struggles most. Three rules keep it thriving: First, drainage beats devotion. Tulsi hates waterlogged soil; if the pot stays soggy, wilting follows even though the soil is wet (root rot, not thirst). Raise the pot on bricks so water escapes freely. Second, watch for pests after rain — sticky leaves or leaf curl on tulsi is almost always insects (mealybugs, whitefly), not a watering problem. Look before you water more. Third, pinch regularly — remove flower spikes and pinch growing tips every 2–3 weeks to keep the plant bushy and leaf-rich. Skip chemical sprays on a plant whose leaves you consume; neem oil and hand-picking are enough.
The most common beginner mistake in container gardening isn't neglect — it's love, in the form of too much fertilizer. Pots hold a small, closed root zone; a dose that a garden bed would shrug off can scorch container roots in days (brown leaf tips and edges soon after feeding are the telltale sign, sometimes with white crust on the soil). The safe habit: use HALF the packet dose, monthly, and watch the plant's response — you can always add more in two weeks, but you can never take it back out. Alternate gentle chemical feeding with organic vermicompost, and flush pots with plain water every month or two so salts don't build up. Your plants will tell you when they're happy: steady new growth beats forced, floppy lushness every time.