Elephant Ears, which belong to the genera Colocasia and Alocasia, are tropical plants prized for their exceptionally large, dramatic foliage. Because these plants originate in warm, humid climates, their tubers—often mistakenly called bulbs—are highly sensitive to cold. Successfully growing them requires precise timing to ensure the soil conditions are warm enough for them to break dormancy and thrive.
Determining Optimal Outdoor Planting Time
The most reliable indicator for planting Elephant Ear tubers outdoors is the complete absence of frost. These heat-loving plants will not tolerate freezing temperatures. Gardeners must wait until all danger of the last expected spring frost has passed in their specific region before considering outdoor planting.
Beyond the air temperature, the temperature of the soil is a direct physical constraint on the tuber’s ability to grow. Elephant Ear tubers require the soil to be consistently warm, ideally reaching a minimum temperature of 65°F (18°C) before they will initiate growth. Planting when the soil is below this threshold often leads to a lengthy dormancy period or, worse, the tuber decaying in the cool, wet ground. Using a soil thermometer to check the temperature at a depth of about four inches is the most accurate method.
In many temperate regions, this ideal soil temperature is typically achieved in late spring or early summer, sometimes weeks after the last air frost. Planting too early, even if the frost risk is gone, exposes the tuber to cold, damp conditions that mimic the environment where fungal pathogens thrive. Waiting for the soil to warm up ensures the tuber is planted into an environment that promotes rapid sprouting and robust growth. Conversely, planting too late can shorten the overall growing season, which may reduce the potential size of the foliage.
Getting a Head Start by Starting Indoors
Gardeners in regions with shorter summer seasons often choose to pre-sprout their Elephant Ear tubers indoors to maximize their growth window. This strategy involves starting the tubers in a controlled environment approximately four to six weeks before the last expected frost date. By the time outdoor planting conditions are met, the plants will already have developed foliage and a strong root system, leading to earlier maturity and larger plants.
To begin the process, select a container slightly larger than the tuber and fill it with moist potting mix. The tuber should be planted shallowly, with the pointed side facing upward, and covered with only about one to two inches of soil. The container must then be placed in a very warm location, ideally maintaining a temperature around 68°F (20°C) or higher, to encourage the tuber to break dormancy. Providing bright light, such as a sunny window or a grow light, helps the new shoots develop into healthy foliage.
Throughout this indoor phase, the soil should be kept uniformly moist but never waterlogged to prevent rot. Once the risk of frost has completely passed and the outdoor soil temperature has reached the required 65°F minimum, the actively growing plant can be safely transplanted outside.
Proper Planting and Initial Care
Once optimal outdoor timing is confirmed, the physical planting process ensures the best environment for long-term growth. Elephant Ear plants perform best in full sun to partial shade, though they benefit from afternoon shade in the hottest climates to prevent leaf scorch. A sheltered spot protected from strong winds is advisable, as the large leaves are easily damaged or torn.
The soil must be rich in organic matter and capable of retaining significant moisture while still allowing for adequate drainage. Amending the planting area with compost or well-rotted manure helps meet their high nutrient and water needs. When planting, dig a hole that accommodates the tuber, placing it pointed end up, and covering the top with one to three inches of soil.
Proper spacing is necessary to allow for the impressive mature size of the foliage; larger varieties often need at least three feet of space between plants. Immediately after planting, water the soil thoroughly to settle it around the tuber and initiate root growth. Elephant Ears require consistent moisture throughout the growing season, so the soil should never fully dry out. Regular application of a high-nitrogen liquid fertilizer every few weeks supports the development of massive leaves.