The sight of an avocado seed turning reddish-brown or pink during sprouting is common. This discoloration often sparks concern, but it is simply a chemical reaction occurring on the seed’s surface after removal from the fruit. This natural process is not a sign of failure or disease, but a normal part of the seed’s interaction with its new environment.
The Chemical Reason Behind the Red Color
The shift to a reddish hue is directly linked to the high concentration of tannins within the avocado seed. Tannins are polyphenols, naturally occurring biomolecules that serve as the plant’s defense mechanism. The seed contains a milky, bitter liquid rich in these compounds, particularly in the outer layer.
When the seed’s surface is exposed to oxygen and water during sprouting, the tannins begin to oxidize. This chemical reaction forms a reddish-brown pigment on the surface. This is the same enzymatic browning reaction that causes a sliced apple or cut potato to darken.
The color change is essentially the seed’s way of responding to exposure. The resulting reddish layer is harmless to the seed’s viability and is considered a natural occurrence during the initial stages of germination. It indicates that the seed’s internal chemistry is active and reacting as expected to the change in environment.
Red vs. Rot: When Should I Worry
It is important to distinguish this harmless, oxidized redness from true seed decay. Normal tannin oxidation typically appears as a uniform reddish, pink, or light brown stain, often localized to areas exposed to air or water. The seed’s structure remains firm, and it should not emit any foul odor.
Signs of actual rot or failure are visually and texturally distinct from simple discoloration. True decay is indicated by slimy, mushy, or soft spots suggesting bacterial or fungal degradation. A rotting seed may also develop fuzzy, white, blue, or black mold growth, particularly near the waterline or where the seed has cracked open.
If the entire seed begins to warp, shrivel, or turn a dark black or deep brown color, it is likely no longer viable and should be discarded. A healthy seed, even with red spots, maintains a firm structure and produces white, clean roots. A sour or foul smell definitively indicates decay.
Handling the Seed During Sprouting
Once you confirm the redness is normal oxidation, focus on providing the best conditions for successful sprouting. The most important preventative measure against rot is changing the water frequently, ideally every one to two days. This practice prevents the buildup of bacteria and mold spores that thrive in stagnant water.
The seed should be kept in a location that receives bright, indirect sunlight. Too much direct sun can dry out the seed or encourage excessive algae growth in the water. When suspending the seed with the toothpick method, ensure that only the bottom third to half of the seed is submerged. The flatter, broader end should face down, as this is where the taproot emerges first.
Once the taproot reaches approximately three to six inches in length and a stem begins to grow from the top, the seed is ready to be transitioned to soil. Plant the sprouted seed in a pot with drainage holes, making sure to leave the top half of the seed exposed above the soil line. This exposure helps prevent the upper part of the seed from rotting once it is placed in a moisture-retaining medium.