Information on ashing in Steiner's Agriculture Course
In his agricultural lectures, Rudolf Steiner explained the method of ashing in the context of weeds as well as animal pests. His sixth lecture was entitled The essence of weeds, pests and so-called plant diseases in the forum of nature.
R. Steiner spoke about ashing of
Weed seeds:Unkraut
You see the weeds growing rampant in a given year. You must accept the fact. Do not be alarmed; say to yourself: Something must now be done. So now you gather a number of seeds of the weed in question. For in the seed the force of which I have just spoken has reached its final culmination. Now light a flame — a simple wood flame is best — and burn the seeds. Carefully gather all the resulting ash. You get comparatively little ash, but that does not matter. Quite literally, for the plants thus treated by letting their seeds pass through the fire and turn to ash, you will have concentrated in the ash the very opposite force to that which is developed in attracting the Moon-forces. Now use the tiny amount of substance you have thus prepared from a variety of weeds, and scatter it over your fields. You need not take especial care in doing so, for these things work in a wide circumference. Already in the second year you will see, there is far less of the kind of weed you have thus treated. It no longer grows as rampantly. Moreover, many things in Nature being subject to a cycle of four years, after the fourth year you will see, if you continue sprinkling the pepper year by year, the weed will have ceased to exist on the field in question.
Field-mice:
Thus you obtain your burned mouse-skin at the time when Venus is in Scorpio. And there remain, in what is thus destroyed by the fire, the corresponding negative force as against the reproductive power of the field-mouse. Take the pepper you get in this way, and sprinkle it over your fields. In some districts it may be difficult to carry out; then you can afford to do it even more homoeopathically; you do not need a whole plateful. Provided it has been led through the fire at the high conjunction of Venus and Scorpio, you will find this an excellent remedy. Henceforth, your mice will avoid the field. No doubt they are cheeky little beasts; they will soon come out again if the pepper has been so sprinkled that a few areas remain unpeppered in the neighbourhood. There they will settle down again. Undoubtedly the influence of it rays out far and wide; nevertheless, it may not have been done quite thoroughly. But the effect will certainly be radical if the same is done in the whole neighbourhood.
Insects:Kartoffelkaefer
In this case you do not take part of the insect as you do with the mouse. You must take the entire insect. An insect like this, which settles harmfully in the plant-root, is altogether an outcome of cosmic influences; it only needs the Earth as its underlying basis. Therefore you must burn the whole insect. It is best to burn it; that is the quickest way. You might also let it decay; possibly this would be even more thorough, only it is difficult to collect the products of decay. But you will certainly attain what you need by burning the whole insect. Now it is necessary to perform this operation when the Sun is in the sign of Taurus. (If need be, you can keep the insect and burn it when the time comes). This, you sec, is precisely the opposite of the constellation in which Venus must be when you prepare your mouse-skin pepper. In effect, the insect world is connected with the forces that evolve when the Sun is passing through Aquarius, Pisces, Aries and Gemini and on to Cancer. In Cancer it appears quite feebly, and it is feeble again when you come to Aquarius. It is while passing through these regions that the Sun rays out the forces which relate to the insect world.
Reference:
Steiner, R. (1924/1958): The Agriculture Course. Translated by George Adams. Bio-Dynamic Agricultural Association, Rudolf Steiner House, London
Citations taken from: http://wn.rsarchive.org/Lectures/Ag1958_index.html
Steiner used the term pepper for these ashed substances. Experiments have been done repeatedly with plant seed pepper, whereas only very few experiments dealing with burnt animal pests are reported.