The above article is taken from the online Vaastu Shastra courses that are conducted by Institute of Vedic Astrology Indore.
If the fertility of a particular land is good, then seeds will germinate very fast there. Green vegetative environment gives peace to the mind. Residents of such lands get progress. If this land is unfertile, then vegetations cannot grow on such land. This will create a dry and unsuitable environment and will take away peace of mind. That is why fertile land is treated to be best for living.
In this test various seeds like wheat, rice, bean, paddy etc. are sown in the soil and their sprouting time is studied. If it sprouts in 3 nights then the land is very auspicious. If it sprouts in 5 days then land is medium and its fertility is less. It can be used for living. If the sprouting does not happen in 7 or more nights then the land is unsuitable for living because it is unfertile.
In constructing houses, testing of flow of wind is also an important factor under consideration as per Vastu. If the flow of wind is proper then the place is ideal for living.
For this test take soil from the land and throw it up in the air. If it floats in the air then it is good sign. But if it falls down instantly, then it is not considered good. Some falling down and some floating is medium condition.