Bag the tropical water lily pod. Any plastic bag will do, particularly one that zips up securely. If a zip-up bag is not obtainable, secure bag loosely around the pod stem with a twist tie. Fill bag with water. After several days, the pod will rupture and the seeds will float to the top of the bag to the surface.
Fill a small bucket with water. Place the complete contents of the plastic bag into the bucket. Wait several days. Eventually, unnecessary parts of the pod and flower will fall away and leave seeds in the bottom of the bucket, which can then be used. Remove the unnecessary pod parts, leaving only the seeds. Examine the seeds and sort them by color. Small red and tan seeds can not be used, but the larger, darker seeds that are typically green and black can be harvested for planting.
Extract the large, dark seeds from the bucket and place them on some drying surface, such as paper towels. Once the tropical seeds are fully dried, they can be stored for later use. Place the seeds in a refrigerator until you are ready to plant them. They can be stored for quite a long time using this method, so no need to fret and scramble to plant the seeds.
Treat seeds in one of two ways. Either plant them prior to sprouting, or subject them to warm water and allow them to sprout before they are planted.
Choose a potting container that is the appropriate size for the number of seeds being planted. Put soil in the container and add water to the soil. Allow soil to settle after adding the water, and then inject the soil with the seeds. Do not immediately add water after adding the seeds, as this may cause the seeds to become unsettled and detached from the security of the soil.
Wait. Over time, the seeds will each begin to sprout small leaves. At this point, they are safe to be transferred once more. The seedlings must be ever so gingerly dug up and moved to be planted individually at this juncture. Remove them from their pots and quickly replant them. Continue to care for the seedlings and eventually they will grow into flowers and bloom, and the cycle of harvesting seeds can begin anew.