Coconut seeds require moisture and warmth to germinate. They are tolerant to the salinity of sea water, but do not tolerate temperatures below freezing. For optimal growth, the coconut tree requires temperatures above 72 degrees and high humidity.
About.com says that coconuts require six months or more to germinate. Due to the length of time between planting and sprouting, the site recommends testing coconuts by dropping them in water before planting. Fruit that floats in water lacks the endosperm required to produce a new sprout.
Upon planting the seed, it is important to provide the warm, moist atmosphere required for growth. A window box in a steamy bathroom provides the ideal location, but covering the container with plastic can artificially provide the moisture needed for germination. Coconuts and other palm seeds often shrivel and appear dead before sprouting.
Once the seed sprouts, move it to a warm, sunny location that provides the humidity for growth. Transplanting seedlings too early has the potential to damage roots. While the germinating seed does not require fertilizer, it is beneficial to the young plant. As temperatures begin to rise, moving the container outdoors provides more sun to encourage growth. Once coconut palms are established, they require seven years before bearing the first fruits.