A person's housescope is based on his place of birth. Life's destiny starts from the place where any individual is born. This is practical Vaastu. If you select quality seeds and if you throw it in fertile land, you can expect very good yield. Similarly, if you select a good plot for construction of a house and with perfect Vaastu you will prosper very well and the sons and daughters will be blessed with good life.
If you select a bad quality seed even if it is thrown in a fertile Land the result will be very minimum. Like that if you built a bad house with bad Vaastu in a good place the prosperity will be very minimal. If you select a bad seed and throw it on bad land the result will be very disastrous.
In the same way, when the land is bad and the house construction is also bad according to Vaastu, the family will face disastrous results. In the case of many constructions, we find that they remain incomplete for several years. This is because there is some thing wrong with the Vaastu of that building and the place.
Before selecting a plot one has to be careful in which direction the house is facing and from the house in which direction you are moving towards the road. Any solid object on Earth emits the invisible energy rays to all directions, similarly it receives the invisible energy rays from all directions. When a person (solid object) staying in a place will be effected by his staying, moving from that house Positively or Negatively.
Source : Vaastu Shaastra by Pullarao