Flower bulbs are specialized underground storage organs designed to contain the necessary food reserves to produce foliage and flowers. These dormant structures, whether a true bulb like a tulip or a corm like a gladiolus, hold the promise of future blooms. Assessing the viability of bulbs before planting is important to ensure successful growth. A quick inspection prevents the introduction of disease into the garden soil and helps identify and discard any bulbs that will not thrive.
The Visual Inspection
The initial assessment of a flower bulb begins with a thorough visual inspection for signs of decay or damage. Healthy bulbs generally exhibit a uniform color, ranging from light tan to deep purple depending on the species, and have a dry, intact outer skin called a tunic. The presence of mold is a clear warning sign, typically appearing as fuzzy patches of blue, gray, or white on the surface.
Discoloration that penetrates the surface is a serious indicator of internal rot. Large, dark spots, especially black or deep brown lesions, suggest fungal or bacterial infection. Bulbs that appear shriveled, excessively dry, or noticeably lighter than others are likely desiccated and may lack the energy reserves to sprout. A healthy bulb should show a small, firm sprout emerging from the apex; soft, dark, or withered sprouts suggest a problem. Visible holes, tunnels, or large cuts are cues that pests or mechanical damage have compromised the structure, making it susceptible to pathogens.
The Tactile and Sensory Check
Once the visual check is complete, the next step involves a hands-on, sensory evaluation. A firm texture is the most reliable indicator of a healthy bulb, confirming the internal tissues are plump and full of stored nutrients. Applying gentle pressure, often called the “squeeze test,” should reveal a solid interior, similar to a raw potato.
Any bulb that feels soft, mushy, or spongy when pressed has likely succumbed to internal rot or excessive moisture damage. Weight is another valuable cue; a viable bulb will feel heavy for its size, correlating with high moisture and nutrient content. A bulb that feels suspiciously hollow or light indicates severe desiccation or decay. Finally, a healthy bulb should have a neutral or mildly earthy scent, while a foul, sour, or distinctly moldy odor is a strong indicator of bacterial or fungal infection and should prompt immediate disposal.
Salvaging Minorly Damaged Bulbs
Bulbs that display only minor, superficial damage can often be saved through careful intervention. If only a small patch of surface mold is present, it can be gently brushed off or the affected outer tunic layers can be peeled away. For minor surface contamination, a simple wash in a dilute solution of water and a 10% bleach solution, followed by thorough air drying, can prevent further spread.
If a small, localized soft spot or lesion is found, a sharp, clean knife can be used to excise the damaged tissue until only clean, healthy flesh remains. The resulting wound should then be dusted with a protective agent, such as a commercially available fungicide or sulfur powder, which acts as an antiseptic barrier. However, a bulb is beyond saving if the basal plate—the flat, bottom section where roots emerge—is completely rotted, discolored, or detached, as this structure is incapable of producing new roots.