Growing hyacinths in glass jars offers a delightful way to bring the beauty and fragrance of spring indoors, even during colder months. This method provides a unique visual experience as you observe the intricate root development alongside the vibrant blooms. Their sweet, pervasive scent and striking appearance make them a welcome addition to any indoor space.
Selecting Your Bulbs and Glass Jar
Choosing suitable hyacinth bulbs is an important first step for successful indoor forcing. Look for bulbs that are firm to the touch, without mold, soft spots, or visible damage. Larger bulbs (16-19 cm) often produce more robust flower stalks and fuller blooms.
It is important to select bulbs labeled as “prepared” or “pre-chilled,” as they’ve already undergone a specific temperature treatment for early indoor flowering. If you cannot find pre-chilled bulbs, chill regular hyacinth bulbs in a refrigerator for 12-14 weeks, away from ripening fruits that emit ethylene gas and inhibit flowering. Specialized hyacinth forcing vases are ideal, featuring a wide base for water and roots and a narrow neck that suspends the bulb just above the water line. Clear glass jars allow you to observe root growth, and various glass containers, including repurposed jars, can work as long as they hold the bulb securely above the water.
The Forcing Process Step by Step
Begin the forcing process by carefully placing the hyacinth bulb into your glass jar. Position the bulb with its pointed end facing upwards and the flatter, root-producing end downwards, ensuring the base hovers just above the water level without making direct contact. Direct contact between the bulb and water can lead to rot, so maintaining this small gap is important. Adding charcoal to the water can help keep it clear and prevent algae growth during the rooting period.
Following placement, the bulb requires a chilling period to mimic winter conditions, which is crucial for proper flower development. Place the jar in a cool, dark environment, such as a refrigerator, unheated basement, or cellar, where temperatures consistently remain between 40-48°F (4-9°C). This cold period should last for 10 to 14 weeks, allowing the bulb to develop a robust root system. During this time, regularly check the water level and replenish it as needed, ensuring it consistently stays just below the bulb’s base.
Once roots have sufficiently developed, often filling a significant portion of the jar, and a shoot emerges, 1-2 inches (2.5-5 cm) tall, the bulb is ready for its transition. Gradually introduce the jar to brighter, slightly warmer conditions over several days to a week, avoiding direct sunlight initially. This slow acclimation helps prevent rapid, leggy growth and ensures the plant develops strong stems. Finally, move the jar to its permanent display location, an area with bright, indirect light, to encourage the flower stalk to fully emerge and bloom.
Ongoing Care for Thriving Blooms
Once your hyacinth is actively growing and preparing to bloom indoors, consistent care will help ensure a vibrant and lasting display. Place the jar in bright, indirect light, as direct, intense sunlight can cause blooms to fade quickly. Maintaining a cool room temperature, below 65°F (18°C), will help prolong the blooming period.
Regularly inspect the water level, ensuring it remains just below the bulb’s base, allowing the roots to access moisture without the bulb sitting directly in water. Change the water every few days to a week to prevent stagnation and the growth of mold or algae. Rotating the jar a quarter turn daily helps the plant grow straight and prevents it from leaning excessively towards the light source. While hyacinths in water generally do not require supplemental feeding, a small amount of liquid plant food can be added.
What to Do After Flowering
After blooming, the bulb has expended significant energy and will not rebloom indoors. Indoor-forced hyacinth bulbs are often treated as annuals and can be composted. To save the bulb, plant it outdoors for future blooms.
To prepare the bulb for outdoor planting, remove the faded flower spike but allow the foliage to remain until it yellows and dies back. This allows leaves to photosynthesize and return energy to the bulb. Once withered, remove the bulb from the jar, clean off any remaining roots or debris, and store it in a cool, dry, dark place (e.g., mesh bag) until fall. Plant the bulb 4-6 inches deep in well-draining garden soil during autumn for reblooming in subsequent years.
Addressing Common Hyacinth Issues
Common issues when forcing hyacinths in glass jars have straightforward solutions. Mold on the bulb indicates excessive moisture or insufficient air circulation. Adjust the water level so the bulb isn’t touching and improve air flow.
Leggy or stretched growth (thin, elongated stems) results from insufficient light after the chilling period. Move the plant to a brighter, indirect light location for more compact growth.
Lack of root development or slow growth during chilling indicates an insufficient cold period. Extend chilling duration, ensure consistent temperatures, and verify the location is dark and cool. Bulb rot is caused by the bulb sitting directly in water; always keep the water level just below the bulb’s base to prevent this.