Jason discusses how to improve drainage in both containers and gardens, especially on heavy clay soil found on Nicomen Island. He demonstrates how to test drainage using peat moss and perlite, where a mix of six cups retains some moisture, taking approximately one minute and twenty seconds to drain half a cup of water. In contrast, coarse gravel drains almost instantly, demonstrating that finer materials hold water and slow down drainage. Jason explains that potting mixes with more peat moss or coconut fiber drain slowly, while those with larger chunks like bark, coarse perlite, or pumice drain faster. He further explores a demonstration involving layering gravel at the bottom of a container filled with potting mix. Surprisingly, the drainage slows down rather than speeding up, taking over a minute and a half before finally draining. This result is attributed to the combination of fine-textured potting mix above and the coarse gravel below, which stalls the drainage process as the finer material retains water and creates a barrier in the flow of water. Jason's presentation emphasizes how understanding these principles of soil texture can help improve drainage in gardening.