The Gravitational Bonsai Hypothesis offers a new way to prove the existence of the "graviton", a mysterious particle that carries the force of gravity, without the need to build multi-billion dollar giant machines. For a long time, the global physics community has heavily relied on super-large instruments like CERN, which smashes particles at extreme energies, or LIGO, which detects macroscopic gravitational waves from black hole collisions. This research takes a completely different shortcut by utilizing the universe itself as a natural laboratory that has already been running for millions of years. To mathematically formalize this mechanism, the author introduces and formulates a new theoretical framework designated as the Bonsai-Denis Law, which scales the ultra-weak bias accumulation through a macro-microscopic integration process. The basic idea of this research uses an analogy from the shaping process of a bonsai tree. A bonsai tree does not change its shape overnight, but instead grows slowly following the direction of the guiding wire for years until its shape becomes permanent. Through the exact same principle, this hypothesis proposes that quantum gravity provides an extremely small steering or directional bias when atoms attach to one another to form a material. Although the effect is ultra-weak and constantly bombarded by thermal noise or random heat disturbances, this gravitational bias works consistently in one direction over a very long period. Monte Carlo simulation results show that when the number of particles reaches millions and grows very slowly, the surrounding random noise will cancel each other out. Conversely, the subtle trace of gravity will accumulate and form a distinctive elongated vertical pattern on the final structure of the material. This paper comprehensively details the critical noise reduction mechanisms required to isolate the signal, mapping out potential interfering noises such as mechanical vibrations from the laboratory floor, axial pressure from superfluid helium turbulence, cryogenic temperature drift, and unwanted diamagnetic torque from external fields. Crucially, a strict falsification criterion is established where the hypothesis will be proven wrong if the aspect ratio remains perfectly isotropic under all cross-material evaluations. All the necessary empirical methods, log-in protocols, and data filtering steps are fully detailed within this text to ensure experimental reproducibility. For any academic discussions, constructive criticisms, or potential experimental collaborations, readers are highly welcome to contact the author directly via the email address listed in the preprint.