Lime-Silica polarity | Term used in Biodynamics. It refers to the notion that the outer planets, meaning those beyond the Sun, namely Saturn, Jupiter and Mars exert ‘silica’ or warmth forces linked to the perennial nature of plants and their ‘food’ quality. In contrast the inner planets, the Moon, Venus and Mercury exert ‘lime’ or watery forces which influence annual growth and reproduction. In Ian Bailey’s words ‘a polarity is established between silica and limestone, outer and inner, expansion and contraction, light and dark, nourishment and reproduction, the Horn manure 500 and Horn silica 501 spray preparations.’ 

‘Rudolf Steiner saw the erosion of ‘spiritual forces’ in nature; and that as a result farming was having to cope with excess growth forces in both crops (weak plants) and weeds (too many). Steiner saw two different growth forces entering the world from the cosmos and in two different ways. The inner planets (Mercury, Venus and the Moon) enter the earth via the lime process, go into the earth, and surface upwards. In contrast the growth forces that come from the outer planets radiate down above the earth, and are caught by the silica process. Steiner says the forces of growth and seed production are most effective when the moon is full, radiating those forces down like a kind of lens, into the earth. So the moon is like a kind of receptor, and lensing process of cosmic forces, and if the water cycle is rampant weeds will grow as well as the crops the farmer is trying to grow. If weed growth is rampant Steiner suggests weed ashing; and if pests are rampant Steiner suggests ashing the animal pest when Venus (which is embedded in Moon forces) is in front of Scorpio, (Aonghus Gordon, 2004).


Aonghus Gordon, 2004, ‘From The Healing Power of the Biodynamic Landscape, reflections on Lecture Six of the Agriculture Course, by Aonghus Gordon’, printed in Star & Furrow 102, p4-9, from a transcript (edited by Jane Cobbald) of a lecture given at the Anniversary Conference in May 2004.

Ian Bailey, ‘Auspicious sowing days – the cosmic aspect,’ Star and Furrow 125 July 2016, p22-24.