How to grow pyrethrum in a biological way
The cultivation of the pyrethrum plant (Tanacetum cinerariifolium) (Trevir.) Sch.Bip. o (Chrysanthenum cineralifolium) is one of those techniques that can insert, within our small cultivation or farm, an element of enrichment exploiting the peculiarities of this plant.
Properties due to the presence of pyrethrins naturally produced by this plant and particularly present in its flowers. Just rub the leaves of this plant in your hands, which gives off a characteristic odor and acts as a repellent for insects and pests.
Obviously the major insecticide property is linked precisely to the pyrethrins that are compounds that act on the nervous system of insects.
This is why the hypothesis of the cultivation of the pyrethrum plant can be implemented (as well as for embellishment of the fields) or as a natural repellent for many harmful insects of agricultural crops or for the direct extraction of pyrethrum to be administered later if and when needed. In fact, it should be remembered that, although it is a natural product and is allowed in organic farming, this does not mean that it does not have its own toxicity and should be used with care and the necessary precautions.
To grow the pyrethrum plant, the first thing to do is to find the seeds Tanacetum cinerariifolium that can be found online or in consortia and specialized stores. It is important to use this species and not similar plants that have smaller quantities of pyrethrins.
Cultivation can therefore be done in flowerbeds or field margins as a repellent effect of insects or in specific productions. Even if it grows a little everywhere it is important to choose sunny areas (if we want more concentrations of pyrethrins) and, even if it takes advantage of mild and warm climates, it also bears cold and winter frost.
Also with regard to soils it fits well everywhere but it is better to choose where there are no stagnations or excesses of clays. Once sown broadly in the period of March it will have to be irrigated regularly during the spring-summer period.
For fertilization it is first necessary to understand what the objective of cultivation is; if you plant the pyrethrum in flowerbeds at the edges of the fields, it is sufficient to extend the fertilization (with mature manure or other organic) to the flowerbeds. If, however, you are looking for special pyrethrum fields, you will have to dedicate an exclusive organic fertilizer to this plant. Some also recommend the use of chemical fertilizers. This technique is highly discouraged because chemical fertilizers (especially nitrogen) weaken and diminish the properties of this plant. Fertilization, in specialized fields, should be done well in the pre-seed period (at least a month before) to allow a good chemical and biochemical interaction between the organic fertilizer and the soil particles.