Indian traditions are very special, unique and meaningful. There is a lot of science behind the various Indian customs and enough explanation too. Let us take the example of sprouting seeds. Often you would see, most of the Indian functions have all this and more.
It is very common practice to grow small plants in the house. But sprouting the seeds during a pooja ( religious Indian function) and watching it grow is a special way of endorsing positive energy in the house. Plants are a source of positivity and growth in the house. That is the reason we should have at one green plant in the house. Invariably all Indian functions have the practice of sprouting nine kinds of pulses and grains and letting them grow. The sown pulses are watered everyday thus signifying growth and prosperity. When there is a festive occasion, these are thrown into the river or artificial ponds thus signifying throwing of evil for a better cause.
Navdhanya is inclusive of grains like maize, millet,barley, wheat, pulses if any and some other small grains. This is usually done during Navratri, a festival of colours in India and is basically meant to ward off evil spirits and do away the bad and retain the good.
The immersion of the sprouted plants signifies burying the past and getting ready for the present. These are also done during weddings and such important occasions. Plants give out oxygen and taken in carbon di oxide. Such plants when grown produce a cleaner and fresher air thus absorbing all negative energy in the surroundings. This is the reason, most of the Indian festivals have the practice of sprouting the navdhanya or the new plant.