Biodynamic Basics Biodynamic spray Equisetum (Field Horsetail)

Biodynamic basics: Horn Silica – “Making your Garden Glow”
6th March 2020
Biodynamic Basics: Tuning into Nature – Star Gazing
3rd November 2019
Biodynamic basics: Horn Silica – “Making your Garden Glow”
6th March 2020
Biodynamic Basics: Tuning into Nature – Star Gazing
3rd November 2019

“So wonderful is its nature, its mere touch staunches a patient’s bleeding”.
Pliny AD 77

The common field horsetail, Equisetum arvense, is a truly remarkable plant. It belongs to the unique genus, Equisetum, primitive prehistoric plants that thrived 350 million years ago. Well known to ancient herbalists to prevent bleeding, their brittle stems contain more silica than any other species, so much so that one species , nicknamed Dutch/Scouring Rushes, were sold to polish metal and used by dairymaids to scour milk pails.

Along with horn manure and horn silica, it is one of the 3 important BD spray preparations (activators). Aptly described as the ‘crowd controller’, its role is to help fight against conditions that thrive in damp conditions such as debilitating moulds, or aphid attacks in greenhouses. It’s a classic example of using Nature to find her own solutions. It’s applied as needed from early spring through early winter and is easy for home gardeners to make. It can also be bought.

Where to find horsetail
Horsetail is found growing wild by ditches, shady riverbanks, and thrives in damp, light, poor soils. Its ability to thrive in these conditions is a clue to what makes it so useful.
Horsetails look like no other plants so are easy to spot. To check you have the correct horsetail, Equisetum arvense, download our helpful identification guide here.

How it’s used
Equisetum is used both as a tea and a concentrated fermented brew. Both can be used as a foliar spray on plants/crops and the soil, though being more dilute, the tea tends to be used more as a foliar spray, and the fermented brew as a drench on the soil. The two complement each other. As a foliar spray in the greenhouse, for example, the tea balances the moist environment and helps prevent aphid, whitefly, fungus, and damping off. As a soil drench, the fermented brew is said to help balance beneficial fungal and bacterial organisms in the soil by increasing their populations.

Picking and drying Equisetum
To ensure the best quality, pick the fronds and stems, cutting them at the base, before mid summer. For a year long supply you can dry the equisetum easily by laying it out on a kitchen cooling rack to allow for air circulation in a warm sunny place until it feels dry and brittle. It can then be stored in a paper bag in a dry place ready to use as you need it.

a) To make Equisetum Tea
Simmer 50-100g fresh horsetail in 1-3 litres of rainwater in a covered pan (eg a stock pot) for 30 minutes.Turn off the heat, and let the infusion cool. When cold, strain the liquid, transfer to bottle(s) or a similar suitable container with a lid. It is now ready for use, and will keep for several weeks. For long term storage, use fermented equisetum.

Note: For smaller quantities, and when fresh horsetail is not available, simmer 25g of dried equisetum in 1 litre of water, for 30 minutes and let stand and cool for 24 hours. Strain and bottle as above.

b) To make Equisetum Ferment
Fermentation increases the concentration and shelf life. Boil and cool the infusion as before but transfer to a clean bucket, cover with sacking or an old cloth / breathable material, and leave to ferment for 10-14 days, or until a white mould is formed on the surface, and it smells distinctly ‘sulphury’. The length of time to ferment varies with the temperature – fermentation is quicker in warm weather – the important thing is to achieve a good fermentation. Strain and bottle as above. Stored in a cool dark place, it will keep well for up to 6 months.

How to apply Equisetum Tea and Ferment

Both can be used as a prophylactic and a treatment, though as a prophylactic, the stronger ferment is recommended. The tea is usually applied diluted 1:5, preferably in rainwater, and the ferment 1:10. For prophylactic treatments dilutions, up to 1:50 have been effective.

  • Only dilute just before you’re ready to use. Stir /dynamise in the usual biodynamic fashion for 15-20 minutes.
  • If spraying, use a garden sprayer set on the fine setting and spray directly on plants /crops misting both upper and lower leaves.
  • The best time to spray is from sunrise to mid-morning. If drenching, drench the soil using a watering can.


When to use Equisetum Tea and Ferment
The two sprays are interchangeable, and are generally used prophylactically in the few days leading up to a full moon, during moist changeable weather when conditions are conducive for fungal attack/aphids etc.

They can be especially useful to prevent fungal problems if the full moon also coincides with a “perigee” moon – this is when the moon is closest to the earth and results in a much stronger ‘watery effect’ from the moon, which the sprays counteract.

If plants /crops are already effected by fungal disease repeat spraying is necessary. Spraying at least 3 times at ten-day intervals has been shown to be most effective; for repeat spraying a more dilute tea solution can be used 1:10

In severe cases the more concentrated solution can be sprayed on and around the affected plants for 3 days in succession.

  • Both the tea and fermented brew can be added to the water prior to stirring horn silica and sprayed out together.
  • A combination of equisetum & stinging nettle teas (mix the two together) sprayed onto plants is excellent to cleanse the plants and stimulate the soil. This video shows how to make nettle tea.

What’s the difference between Horn Silica and Equisetum ?
Both of these important aids rely on the strengthening power of silica but work quite differently.
Horn silica – also referred to as the sunshine tonic stimulates upward growth, enables plants to photosynthesis more effectively, and connects to the forces of light and heat.

Equisetum works on the downward forces, and counteracts the watery influence of the moon, which accentuated in plants (weak, sappy growth) is conducive to fungal and insect diseases. Equisteum sprays counteract this by having a drying, balancing effect to strengthen the plants and ‘push away’ disease.

Further reading
BD Soil activator – horn manure
BD Sunshine tonic – horn silica