Purines; infusions, ferments and plant macerations

Purines; infusions, ferments and plant macerations

Ruth Sellers June 29, 2019

It consists of providing our crops with substances that come from other plants either in infusions, macerations or fermentations. Indistinctly they can be applied as much in the irrigation as in fumigation on the plant although this second application is more effective.

In conventional agriculture – chemical agriculture – we always consider the contributions we make to the soil based on an isolated plant and the needs it is supposed to have the plants, nitrogen, phosphorus, potassium, and so on. The soil is seen as simple physical support were to take root but inert to practical effects. The plant must be given all the elements it is supposed to need. In a way, plants are considered to be fragile and defenceless beings that must be over-protected – and made dependent!

“Organic farming interprets the balances of ecological systems as very stable and solid, but they are also very complex. It is the living soil that allows plants to manifest their vitality, robustness and offer us their full capacity to transmit life.”

Reproducing basic ecosystem principles

Although our knowledge is really very limited, we are beginning to have a fairly clear vision of the principles that govern plant health. The soil where the plants live is like a collective digestive system in which each plant, cultivated or adventitious, favours processes, activates defences, provides enzymes, stimulates certain microorganisms.

It seems that there is communication between plants using chemical messages transmitted by the mycelium of fungi, etc. Trying to understand the whole process before acting would block us! The most sensible thing is to try to reproduce, at least the basic principles of the ecosystem and let the diversity of life develop both microbial and insects and other plants.

Microbial life is of almost absolute importance in the life of the plant world; it relates the plant to the environment, allows it to assimilate nutrients in relation to the temperature of the environment, nitrogen in the air, decompose mineral structures in the soil, or keep the population of microorganisms in balance so that there are no attacks from pathogenic microorganisms. In fact, if we are attentive, we will see that a large part of the traditional soil fertilizer consists of feeding the bacterial flora of the soil.

The application of infusions, fermentations and macerations are various ways of quickly introducing precursors of the equilibrium of the soil: in infusions, we will provide diluted elements, in fermentations, we will provide diluted elements transformed by microorganisms – as they would act in the soil.

“Since we have not been able to incorporate the desired diversity of plants into our orchard, we will provide a biochemical or vital presence of the absent plants.”

The relationship between plants and the soil

Each plant species has the peculiarity of relating in a special way to the chemical reactions of the soil system and of solving certain types of metabolic problems.

We know from experience that certain plants make us improve our ailments; let us not forget that we share biology with them, that is to say our chemistry is practically the same and the same problem that we can have if we cannot get rid of a toxic substance in our organism, is experienced by plants in their collective environment -soil-. The presence of a plant, or of some of its substances or the reaction of the bacterial world to its substances will allow or facilitate the balance of the environment.

We are familiar with the idea that a problem of sucking insects, for example, has to be solved with repellents, odour disorientation, natural insecticides, etc. Instead of thinking that the insects are there because the growth has been disproportionately fast and some substances of the cellular composition of the plants have been missing, or that the nutrients of the soil were in too soluble form… but if we load the insects that caused the problem we will generally only have postponed the problem until later; or we can even import it to our organism.

“The insect is a messenger, it’s not the problem, we must learn to listen!”

Extracts and their applications

Depending on what we are looking for we will make the various applications. In addition to the generic application, some plants can provide specific resources such as growth and flowering stimulants, strengthening tissues to help defend against fungi, improve nutrient assimilation. The options are immense although most are not yet contrasted can ensure that in all cases the vitality of plants and therefore their ability to defend themselves against diseases and predators.

The variety of plants with which we can make purines is extensive; garlic, wormwood, comfrey, nettle, elderberry, rhubarb, onion, tomato, etc..

We can start with two basic plants; nettle and ponytail. Surely they are the purines with which it has been practised more and they conform the basic medicine cabinet of our orchard, without detracting from the rest of preparations. Also, they are some plants that we can find dry, ready for its comfortable use, even out of season.

Elaboration of the extracts

The quality of the water is very important, it must be drinkable – without nitrates – and it must not contain chlorine. The ideal would be rainwater. If it is tap water – with chlorine – should be aerated in a bucket 3 or 4 days. The water should be slightly acidic.

We are going to differentiate four types of extracts; Fermented, decoctions, infusions and macerations.


To make the fermentations we will use robust plastic containers, of greater volume than the one we are going to prepare since it will be necessary to put the plants of the preparation inside the container and to remove. We will be able to cover the container but without preventing it from breathing. It is preferable to make large volumes, minimum of 30 litres, rather than smaller quantities because the results are more regular.

A dose of 1kg of fresh plant per ten litres of water is usually used. If we use dry plant the dose is reduced between 100 and 200 gr. per ten litres of water. The fresh plant should be cut up so that it can extract the substances more easily. Depending on the ambient temperature the fermentation will be faster or slower, between 5 and 15 days.

The container should be stirred every day for a few minutes. We will recognize the fermentation because small bubbles are released that ascend from the bottom of the container. When bubbles no longer rise, the fermentation will be ready for use, we will be able to filter it and store it in closed containers without air.


The infusions are prepared to depart from the plants in cold soak that are heated and when the boiling begins they are removed and they are left to cool. It is important to always make it with a lid to preserve the volatile essences. Sometimes they can be applied a little hot (45ºC) in insecticide use.


Decoctions are, in fact, an infusion that is left to boil in a stainless steel casserole, preferably covered, about 20 or 30 minutes over a gentle heat. It is left to cool and immediately applied.


The macerations are prepared in cold water that consists of putting the finely chopped plant in water for 24 hours, filtered and applied. It usually has a fungicidal function. It is usually used as an immediate application in case of hardship in small gardens or balcony orchards.


Nettle (Urtica diodes) acts as a stimulant plant, accelerates composting, fights ferric chlorosis and promotes photosynthesis. Dilute 5% in foliar spray and 10% for watering plants.

For use as a repulsive plant is used in maceration and repels aphids, mites and carpocapsa. Spray pure extract.

As an insecticide, it is applied in infusion in cold pulverized in dilution to 10%. It fights yellow and red mites.


Horsetail (equisetum arvense) has various functions as a fungicide plant. In decoction, it is effective against monilia, rust, mottling, peach leprosy and some viruses. As repulsive for the leek worm and red spider mite, in the form of fermented. Dilute the extract to 20%. As a preventive measure, apply every 7-10 days.

The subject of preparations and slurry of plants is very broad and exceeds the capacity of this informative article so we will only refer to the nettle and ponytail with the suggestion to turn to specialized books to expand knowledge.

The book “Plants to cure plants” from the publishing house La Fertilidad de la Tierra, is an excellent reference book if you want to go deeper and has contributed a lot in making these techniques known.

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