Amaryllis plants, known for their striking blooms, are a popular choice for indoor gardening. Understanding their specific temperature requirements is important for healthy development and successful reblooming.
Amaryllis Temperature for Active Growth and Blooming
During its active growth phase, amaryllis thrives within a specific temperature range. These plants generally prefer temperatures between 60°F and 75°F (15°C to 24°C) for optimal health and vibrant flowers. Maintaining temperatures around 65-75°F (18-24°C) encourages steady growth and helps prevent stress. A slightly warmer daytime environment, mimicking their natural tropical habitat, is beneficial.
Slightly cooler temperatures at night can promote better flowering. Once the amaryllis begins to bloom, maintaining 60°F to 65°F (15°C to 18°C) helps extend the life of the flowers. Moving a blooming plant out of direct sunlight and into a cooler spot, around 65°F (18°C), can prolong its display.
Amaryllis Temperature for Dormancy
Amaryllis bulbs require a period of dormancy to prepare for their next blooming cycle and rejuvenate energy reserves. This phase is typically induced by cooler temperatures, ranging from 50°F to 55°F (10°C to 13°C), though some sources suggest 50-60°F (10-15.5°C). During dormancy, the plant conserves energy for new leaves and flower stalks.
To initiate dormancy, reduce watering in late summer or early fall and move the plant to a cool, dark, dry location. Leaves will naturally yellow and wither. If dormancy temperatures are not met, the bulb may not store enough nutrients, potentially leading to a lack of flowers. After 8 to 12 weeks of rest, bring the bulb back into warmer conditions to stimulate new growth.
Impact of Extreme Temperatures on Amaryllis
Amaryllis plants are sensitive to temperatures outside their preferred ranges. Temperatures dropping below 55°F (13°C) can slow growth and harm the plant. Freezing temperatures can kill the plant entirely; cold shock can manifest as limp and yellowing leaves, and growth may become sluggish, possibly preventing blooming altogether. Frost or freezing conditions are particularly damaging, and amaryllis will not survive them.
Conversely, temperatures above 85°F (29°C) can negatively affect the plant. Heat stress may cause wilting leaves, faded blooms, and stunted growth. Browning leaf tips can indicate dehydration resulting from high temperatures and increased water loss. Prolonged exposure to heat can also cause blooms to fade quickly.
Managing Amaryllis Temperature
Maintaining appropriate temperatures for amaryllis involves strategic placement and consistent monitoring. Indoors, keep plants away from drafty windows, cold spots, or direct heat sources like radiators and heating vents. Sudden temperature fluctuations can stress the plant, leading to issues like stunted growth or dropped buds.
For outdoor placement during warmer months, ensure the plant is acclimated gradually to brighter light and protected from excessive heat. A shaded patio or a spot with indirect light is suitable, especially when temperatures are high. In cooler climates, amaryllis must be brought indoors before the first frost. Providing bottom heat, such as with a propagation mat, can help stimulate growth if a bulb is slow to emerge from dormancy.