Fermented horsetail tea, for the orchard and the vegetable patch

Horsetail plant leaves to make fermented tea.

Fermented horsetail tea is an effective fungicide that helps avoid most fruit tree and vegetable patch diseases.

Horsetail can be harvested virtually anywhere since it is one of the most common wild plants. Fermented tea is very easy to prepare from it, and waiting time before use is short.

Finally, avoid growing it in your own garden, it is a truly invasive species that will overtake your plot unless you lock it in as if it were bamboo!

An alternative is to have it grow in a large tub. It also does great at the foot of conifer hedges, that can be locked in by pavement on either side.

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Steps to prepare fermented horsetail tea

Basic and most effective recipe

This technique is a simple two-week cold maceration: no boiling, just waiting.

  • Harvest 35¬†oz (1¬†kg) fresh leaves.
  • Add 9¬†quarts (9¬†liters) rainwater (softer).
  • Macerate for 1¬†to¬†2¬†weeks.
  • Avoid using metallic containers for maceration.
  • Mix regularly (twice a day is ideal) or use a bubble blower as for aquariums.
The fermented horsetail tea is ready when the liquid turns black and leaves are reduced to slime at the bottom of the container.
  • Filter to remove any residue and produce a perfectly clear liquid.

Quicker but less nourishing, boiling

An alternative recipe, instead of two-week cold maceration, is to let it macerate for only 24 hours. After this day-long maceration, boil the leaves and water together for 20 minutes. Cool and filter before use. This makes the fermented tea available for use much earlier.

Boiling, however, degrades some of the nutrients of the plant so it won’t have such a high fertilizing side-effect, but that’s a secondary consideration when treating against diseases.

Horsetail tea from dried powder

Out of season, it’s hard to get fresh horsetail. You can still make this “magic potion” from dried horsetail! That way, all you need to do is dehydrate the weeds in season and then rehydrate them later on, when you need to use the plant.

Powdering helps the plant break down faster when preparing the mix, but it will also work well with whole dried plants.

  • Use one-tenth the weight. For instance, instead of 35 oz of fresh leaves, just use 3.5 oz of dried material (100g instead of 1 kg).

Again, you’ve got two options here: you’ll get more nutrients if you ferment this material, but you can use your mix faster if you boil it. For both options, just follow the steps described above, adjusting for dried weight (use only 10% of the basic recipe).

  • Try to add in a couple handfuls of any other fresh weed (nettles, comfrey…). You can also use any low-lying leaves from other plants, without rinsing them off. These will bring in the yeasts necessary for fermentation to start off fast.
  • Adding other yeasts like bread yeast or a live yoghurt also works great.

Other than that, follow the same process!

Using fermented horsetail tea

Fermented horsetail tea is mainly used in spring and in fall, when diseases are most certain to appear.

  • Since it is absolutely harmless to plants, spraying is possible all year round.

Mixing ratio is 10% fermented horsetail tea to 90% water.

  • If my 10-quart (10 liter) sprayer contains 9¬†quarts (9¬†liters) water, I‚Äôll add 1 quart (1 liter) fermented tea and have a great disease repellent.

Spray regularly to avoid all chance of disease.

Diseases that horsetail tea can treat

Horsetail tea is particularly effective against:

Keeping excess fermented horsetail tea

Horsetail plant stems used for fermented tea.Fermented tea can keep for several weeks in a rather cool and dark place.

Again, choose a sealed container that is not made from metal.

Use a wood barrel or plastic jug or barrels.

Avoid iron, copper and other metal-like containers since they would react with active ingredients and render them ineffective.

Most important is to keep the fermented tea “alive”: all yeasts contained in such fermented weeds must be protected from freezing and from heat waves.

Although the base material is free, the time you put in it needn’t go to waste. You can spray leftover tea on healthy plants to give their immune system a boost, too!

Indeed, sometimes fungal diseases are present even if the plants don’t show any symptoms yet. For instance, on some Septoria host plants like tomato, incubation can last from 2 to 4 weeks before the first spots appear.

Smart tip about horsetail tea

When planting flowers or preparing soil mix, moisten the soil up with fermented horsetail tea to cleanse it from damaging fungus.

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Credits for images shared to Nature & Garden (all edits by Gaspard Lorthiois):
Horsetail leaf by Maria Betleja under Pixabay license
Horsetail stems by ArtTower under Pixabay license