Biodynamic basics: Horn Silica – “Making your Garden Glow”

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The biodynamic preparations (activators) are unique  – biodynamic turbochargers primarily responsible for the extra health and vitality of your plants and garden. To see for yourself, watch our video here

Horn silica, the ‘sunshine ‘ preparation, like its companion, the horn manure soil activator, is profoundly important and beneficial: made from a paste of ground quartz (silicon dioxide), buried in cow horns over summer, it helps plants maximise the sun’s energy (photosynthesis), grow strong and resilient  – a hallmark of biodynamic plants, and realise their full potential, including balanced growth, colour, aroma, flavour and nutritional quality.

Biodynamic gardeners everywhere who experience – and taste – its benefits for themselves would not be without their horn silica activator.

For more about the horn manure soil activator, see our feature here

Using horn silica

Horn silica is used in tandem with horn manure. The DK Biodynamic Gardening Book describes it as the “yin to horn manure’s yang”. The two together combine to achieve optimum growth and health. Horn manure, a microbial powerhouse that boosts soil life, helps plants literally root into the earth and thus build a solid foundation. In contrast, horn silica acts as a light enhancer, enabling plants to better utilise light and warmth thus boosting their growth and development to maturity above the soil.

Whilst horn manure is sprinkled in large drops directly onto the soil in spring and autumn, horn silica is sprayed as a fine mist above and over crops as and when needed during the growing season, or sometimes over the whole garden. It also helps plants resist moulds and fungal and pest attacks.

How much to use?:

As our video shows you only need tiny amounts of horn silica – 5g (one unit) stirred in a bucket of rainwater, is enough to cover any garden /allotment up to and including one acre – a little goes a long way.

For how to stir /dynamise horn silica see our video

Buying horn silica:

You can buy horn silica from our online shop here.

When to use:

Horn silica provides three main areas of support during  the growing season

  • To bring a balance of light energy to your garden when slugs and snails proliferate (use in January and February in particular for this)
  • Plant structure and ripening (June – September)
  • Plant health and protection from moulds (mildew), fungal disease, and pests (May – October)

Tips on spraying:

  • When possible use lukewarm clean rainwater; if using tap water, let it stand for 24 hours outdoors in the sun.
  • Whilst plants are in their growth/ formative stage, ideally, spray early in the morning. Aim to finish by mid-morning before the sun gets strong
  • At the end of the growing season, to enhance the final stage of fruit and seed ripening, spray late afternoon.
  • Do not spray when it’s raining, or rain is forecast.
  • Spray when the moon is ascending (rising): this a 2-week rhythm that occurs each month, marked as  “southern transplanting time” in the Maria Thun Planting Calendar. – If you have a sizeable area of one particular crop e.g. currants (fruit), lettuce/spinach (leaf)  or flowers, for optimum effect, you could consider spraying on a Fruit /Leaf /Flower day when the moon is ascending. However, in most small gardens, this is not practical so a spray of all crops during ascending moon is fine.

Note: Just warm the water to around blood temp (37.5 degrees). A simple test for this is to stick your elbow in – if it feels warm then the temperature is likely to be spot on. If the water feels hot on your elbow then let it cool a bit – just like testing best bath water temperature for babies! 

How to know when to use horn silica?

The beauty of biodynamics is that it actively encourages observation and intuition – in short, to develop your own gardener’s green fingers. As the saying goes, practice makes perfect. The more you practice this mindful way to garden, the more you will sense when to use our biodynamic activators and the more your own experience will guide you. Here are a few key pointers to help get you started.

  • When plants are developing well but have not yet reached maturity. For example, it helps hearting up for lettuces; flowering and seed setting for peas and beans and other ‘fruiting’ plants; and root flavour for carrots when growing well
  • On fruit tree flowering and pre ‘June drop’
  • In a damp, cold spring or you feel there is a risk of mould; or use on flower and fruit days in the growing season to ‘push back’ damp, mould and fungal problems
  • In a damp summer
  • When plants seem not to be as healthy as they should be – leaf spots on fruit trees or roses etc.

Storing horn silica

Horn silica will keep indefinitely when stored correctly – dry, in a glass jar with the lid on in a bright place e.g. a window sill. Like all the biodynamic preparations, it’s sensitive and works in subtle ways,  so keep well away from strong electromagnetic forces (EMF) including mobiles, TV’s, fuse boxes, smart metres, routers, computers, sockets etc.

A note on the science behind silica: 

Biodynamics takes a profoundly holistic approach but it’s always useful to know the science as well especially when, as in this case, it mirrors what gardeners and farmers have found in practice

Silica is a key mineral for all plants. To be absorbed it needs to be dissolved in clean water. It works at a microscopic level, strengthens plant cell walls (more upright growth and rigidity), increases the density of roots and shoots, improves uptake and synthesis of certain micronutrients, and helps alleviate toxicity from metals, e.g. aluminium.

Importantly for climate change, it helps protect certain crop species from stress including withstanding heat, drought, pests, and fungal disease This is why it is attracting attention from agro-scientists and why we can expect to hear lots more about it in future.