Horsetail decoction: recipe and garden use

Well known for its effectiveness against cryptogamic (or fungal) diseases and damping off, field horsetail is used as a decoction in the garden. Let’s discover this virtuous plant among the oldest on the planet, see how to prepare a decoction of horsetail and what precautions to take when using it.

Field horsetail: a weed plant with a thousand virtues

Field horsetail (Equisetum arvens) is a rhizomatous perennial plant of the family Equisetaceae. It does not produce flowers but spores that the wind takes care of dispersing in nature. It grows spontaneously along paths, in ditches, embankments, on banks, in fields… wherever it can take advantage of sufficient humidity. Moreover, the presence of horsetail means that a water table is never far away. It likes light soils, composed of sand and silt, that is to say sandy-loamy, slightly acidic.

The only region of the world where field horsetail is absent is Australia. Everywhere else, it has been developing without difficulty since the dawn of time. It is indeed one of the oldest plants in the world. That is to say the ability to adapt which she has. It is also strongly advised not to plant horsetail in the garden as it has a great ability to colonize its environment. Note that it is difficult to eradicate it from the garden when it has settled there. And since it would be a shame to resort to a chemical weed killer to overcome it, you might as well take the lead!

It is given different names such as ponytail, Fox tail or rat tail… Never mind, field horsetail is used for its medicinal virtues but not only, since in the garden, it knows how to make itself indispensable when one wishes to lead a merciless fight against fungal diseases which have not yet attacked all the plantations.

Field horsetail: the gardener’s ally

Horsetail is rich in silica. In the form of a decoction, it is particularly useful in preventive treatment of fungal diseases and in cure, but in the latter case, provided that the plants are moderately affected by pathogenic fungi. Otherwise, it is necessary to resort to a commercial product because an abuse of horsetail would not change anything but can prove to be harmful. Indeed, even though it is a natural solution, it is an active product. Intensive use is never trivial.

It is therefore impossible to obtain convincing results in a garden where many plantations are affected by a cryptogamic disease and the damage is significant. Hence the interest ofact preventively and or at the very beginning of the infestation, that is to say from the first symptoms. This is why it is absolutely essential that the gardener be vigilant and observant.

So we go and take a look at his plantations every day, as far as possible. Regular monitoring of its plants (vegetable or amenity like fruit trees in the orchard) makes it possible to react quickly when necessary and consequently to save flowering or harvests. Let’s not forget that a cryptogamic disease can cause very heavy damage to crops.

Horsetail decoction has antifungal and insecticidal properties. It is particularly useful in the garden for the following reasons:

  • Stimulates the natural defenses of plant organisms,
  • Protects against damping off,
  • Prevents attacks by pathogenic fungi responsible for fungal diseases such as:
    • peach leaf curl,
    • Late blight of tomato, vine and others,
    • Powdery mildew, which attacks roses as well as fruit trees of all types,
    • Monilia frequent in the orchard,
    • The rust that makes all gardeners tremble because it affects many ornamental plants (rose, hollyhock) as well as fruit trees (pear, blackcurrant, gooseberry, etc.), garden vegetables (potatoes, green beans) and even trees, mainly conifers.
    • Fruit tree scab.

It can also repel insect pests.

Horsetail decoction: a natural biodegradable treatment

What we appreciate more in the field horsetail is that it does not present no danger for humans during its use. Contrary to what is recommended for chemical products, whether fertilizers or pesticides, there is no need to wear goggles, gloves and a protective mask when handling it. Of course, nothing prevents you from protecting yourself if you wish.

The icing on the cake, the horsetail decoction is just as harmless to the environment. Biodegradable, it does not pollute the air or the ground, nor groundwater. Let us also rejoice because she has no harmful impact on garden faunabe it bees, butterflies, frogs, lizards, hedgehogs, the very ones on which we rely a lot to disseminate plant seeds or devour harmful insects and other unwanted creatures.

Field horsetail: it is picked in the spring

This is in April or May that the gardener equipped with a shears goes in search of horsetail which will be used to prepare a saving decoction for many of the plants he cultivates. The picking of horsetail takes place by cutting the stems at the lowest.

Back home, all he has to do is reserve part of his harvest for drying in the cellar or the attic, the ideal being that the room chosen is well ventilated and not humid. The other part of the picking is to be used as soon as you return from the fields. Indeed, one can resort to decoctions of dried horsetail and decoctions of fresh horsetail.

Horsetail decoction: the recipe

The equipment needed to prepare and then use this natural mixture based on dry or fresh horsetail is as follows:

  • A plastic bottle that has been carefully opacified by wrapping it in aluminum or other: it is used to collect the juice obtained,
  • A Dutch oven or large saucepan,
  • A stainless steel or plastic bucket,
  • An essential funnel for transferring liquid from the pan to the bottle,
  • A sprayer, preferably backpack and pressure, as it greatly facilitates the treatment of garden plants with horsetail decoction.

First of all, it is necessary to prune the plants if necessary in order to eliminate the roots because it is the only part of the horsetail that is not used in decoction. The method for preparing the decoction is as follows.

  • Coarsely chop the stalks,
  • Place the desired quantity of horsetail in the bucket, namely:
    • 20 g/litre of water in the case of dried horsetail,
    • 100 g/litre of water if using fresh horsetail,
    • 50 g of freshly picked horsetail per liter of water if intended to control damping off.
  • Pour water (preferably rain) into the bucket containing the horsetail, respecting the proportions indicated above,
  • Cover the container, for example with a transparent film or a large lid,
  • Leave the water/horsetail mixture to macerate for 24 hours.

After this rest period, you must extract the active ingredients. This is why the macerated mixture must be decanted into a large saucepan that is put on low heat, then left boil quietly for ½ hour before removing the pot from the heat.

When the mixture is cold, all that remains is the filter using a cheesecloth, a cloth or a paper filter for example, so as to collect only the “juice” in a can or a bottle which it will be enough to finally close hermetically. Horsetail decoction can be kept about twenty days at the most, imperatively in a dark room and away from heat.

Since the shelf life of horsetail decoction is relatively short, there is no need to prepare a large quantity. Hence the interest of drying part of the harvest and then storing it in a large hessian bag, for example. This way you always have it on hand. It will suffice when the time comes to prepare a decoction by following the recipe that we have just discovered in detail and then to use it either as a fungicide or to prevent damping off.


When using it in the garden, it is necessary to remain moderate with regard to the dosages.

  • In watering: maximum 1 volume of decoction for 4 volumes of water, for example 25 cl/100 cl (diluted to 20%).
  • Spraying: you have a lighter hand because the decoction must be diluted to only 5%. One application per month is necessary to prevent mildew and company.
  • Against the damping off: it is simply necessary to soak the seeds to be sown for a few moments in the undiluted decoction of horsetail that has been specifically prepared for this use (see above).

After a heavy rain, it is necessary to treat again because the water tends to to wash treatments, reducing their effectiveness. Finally, logically, it is imperative to stop the use of horsetail decoction (in watering and spraying) 15 days before harvesting garden products and orchard fruits since they are intended for consumption.

Finally, it should be noted that there are several varieties of horsetail, some being easier to find than others in the surrounding nature, as is the case, for example, with marsh horsetail (Marsh Equisetum). But it is the horsetail that is the most effective of all and its harmlessness is proven, which is not the case of that of marshes for example, toxic for horses and many other animals since it contains thiamine.

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