Biodynamic wine relates pre-dominantly to the farming of the fruit from where the wine comes from. Biodynamic wine is made from biodynamic fruit. Like organic wine the grapes are grown without any chemical intervention but this is not central to the practice. Biodynamic farming has holistic roots and follows observations that have been passed down by farmers over many centuries... if you are dismissive of a non-scientific approach bear in mind that some of the most revered and expensive wines in the world are from biodynamic vineyards. Many of its practices can be explained and many can't. Biodiversity on a microbial, plant and animal level are the foundations on which biodynamic principles are built. By creating a diverse and life-enriched environment, fungus and diseases are less prevalent, plants are healthier and a general harmony is established through mirroring nature's eco-systems.
As is often the case, Isabell Legeron explains it best. She states that "[n]atural preparations based on plants, minerals and manures are all used to stimulate microbial life, boost the immune systems of plants, and improve soil fertility." (Natural Wine, 2014).
Controversially biodynamic farmers will observe phases of the moon when making decisions on vitally important treatments. To wait on the changing of a lunar phase to make a decision on something as crucial as harvesting seems unthinkable and totally illogical to some. Dr. Mahajani explains "[p]eople don't realise how bright the moon can be. When it's a full moon, plants grow more... Tides have one of the most profound effects on Earth. Gravitational pull is on everything - on gasses in the air, on land, and in water. Everything is moving up and down - all the buildings, roads, walls, concrete, everything experiences the tide. But, since the bonding of molecules in solids is stronger than those in liquids or gases, it's just less obvious." (Natural Wine, 2014).