Cacti are desert plants adapted to survive long periods without water. Overwatering disrupts their natural rhythm, leading to root rot—a common cause of death. When roots sit in soggy soil, they suffocate and decay, preventing nutrient absorption. Unlike other plants, cacti store water in their stems and leaves, so they require far less frequent watering. Always let the soil dry completely between waterings, and ensure pots have drainage holes.
Cacti thrive in gritty, well-draining soil that mimics their native arid environments. Using standard potting soil retains too much moisture, suffocating roots. A mix of sand, perlite, and coarse gravel is ideal. Without proper drainage, waterlogged soil creates a breeding ground for fungi and bacteria, which attack the cactus’s weakened roots and stem.
Cacti rely on intense sunlight for photosynthesis and growth. Placing them in dimly lit areas forces them to etiolate—stretching unnaturally toward light—resulting in weak, pale stems. While some species tolerate partial shade, most need at least 6 hours of direct sunlight daily. A south-facing window or outdoor spot with full sun is best. Without enough light, cacti become susceptible to disease and fail to thrive.
Though cacti endure harsh desert climates, sudden temperature changes can shock their systems. Drafty windows, air conditioning vents, or rapid shifts between indoor and outdoor environments stress the plant. Cold temperatures below 50°F (10°C) can cause cell damage, while excessive heat without airflow may scorch tissues. Gradual acclimation to new conditions is key to avoiding fatal stress.
A pot too large holds excess moisture, increasing rot risk, while a cramped pot restricts root growth. Cacti prefer snug containers—only 1-2 inches wider than their root ball—with ample drainage. Repotting too often or at the wrong time (e.g., during dormancy) also disrupts their growth cycle. Terracotta pots are ideal, as they wick away moisture and provide stability.
Cacti evolved in nutrient-poor soils, so excessive fertilizer burns their roots and distorts growth. High-nitrogen formulas promote weak, watery tissue prone to pests and rot. Use a diluted, low-nitrogen cactus fertilizer sparingly—only during active growth (spring/summer). Overfed cacti may show yellowing, soft spots, or sudden collapse.
Mealybugs, spider mites, and scale insects target stressed cacti, sucking sap and introducing pathogens. Overwatering or poor air circulation often invites pests. Early signs include white webbing, sticky residue, or discolored patches. Isolate infected plants and treat with insecticidal soap or neem oil. Left unchecked, pests drain the cactus’s energy and spread disease.
Cacti have delicate tissues beneath their tough exteriors. Rough handling, accidental bumps, or improper pruning can cause wounds that invite infections. Always use gloves and clean tools when repotting or removing offsets. Broken spines or scars compromise the plant’s defenses, leaving it vulnerable to pathogens.
Many cacti enter dormancy in winter, slowing growth to conserve energy. Watering or fertilizing during this phase disrupts their cycle, leading to rot or weak spring growth. Reduce watering to once a month and keep them in cooler (but frost-free) conditions. Forcing active growth year-round exhausts the plant.
Most cacti prefer dry air; high humidity encourages mold and fungal diseases. Bathrooms or terrariums trap moisture around the plant, causing stem rot or black spots. Conversely, extremely dry indoor air (e.g., heated rooms) may dehydrate roots. Aim for moderate humidity (40-50%) with good airflow.
