When sowing Sacred lotus or Indian lotus (Nelumbo nucifera), two things are important besides fresh seeds: high temperatures and that the seeds get drilled. In addition to a drill, an electric nail file can be used for this purpose. Drilling or filing must be done until a white shell is visible. This is the lotus nut.
After this pre-treatment, the lotus seeds should be watered for about 48 hours. They can then be placed in an aquarium, water glass or pot filled with substrate.
To prevent the lotus seeds from clouding the water in the aquarium, they must be watered until they no longer give off color.
At 77 to 86 °F (25 to 30 °C), the first seeds can germinate in as little as five days. At first, only leaves will appear, and it may take two to four weeks for the first roots to emerge.
Nelumbo nucifera can be sown indoors throughout the year. But the Sacred lotus is a very large plant and needs a lot of light. Therefore, according to my observations, the seedlings are best kept in a large mixing tub in a full sun location.