Liquid and Foliar Feeds

Howard Tanner

Liquid Feeds
Using enriched water to boost plant growth is a long established practice but this apparently simple task has pitfalls for the unwary even the right choice of container has its importance. In “The Living Soil” Lady Eve Balfour cites the occasion where after years of useful service a galvanised tank rusted through (electrolysis) and was replaced with a wooden barrel. This was situated as before inside the large greenhouse at the nursery so that the water would warm to the house temperature before use. Things went wrong gradually. Plant growth slowed, some began to look sick and yet it was a full 18 months before the connection between the change of the water container and the onset of the troubles lead to a realisation that the plants were zinc deficient. (See ‘The Zinc Solution’ by Professor Bryce Smith). Over many years the galvanised tank had been slowly eaten away, releasing positively charged ions of zinc, which are essential to healthy plant growth, into the water. A wide range of mineral trace elements are vital to the growth of plants.

These days large plastic barrels are the popular choice for water butts and for liquid feed. There is hopefully nothing harmful in this but we must be aware of mineral ion deficiencies. What you put in is what you get out. So, just what do we have to put in to get good liquid feed out?

The Henry Doubleday Research Association, HDRA (now Garden Organic) have faith in comfrey leaf extract. However, there are many other leaves that can be used, together with manures and mineral ion trace elements. There are devotees who with dogmatic allegiance swear by a favoured brew and why not if the mix grows their plants well enough, fine! But, dandelion, dock, ground elder, together with herb leaves all make quality liquid feed. Poultry, rabbit, sheep, cattle, horse and elephant manures will all make liquid feed; finely ground coal dust is absolutely chocabloc full of mineral nutrients.

Now for the icing on the liquid feed cake. Zinc and iron react (electrolysis), releasing positively charged ions into solution; copper and iron also react. Instead of leaving them loose, in my butt they are bolted together and whilst I don’t know if this is of any advantage, it does make it easy to check them. In my father’s day things were different. A sack containing horse manure and soot was suspended in a barrel and we also had an enameled pail with a clipon lid. Part of the duties which earned my pocket money was, each morning, to carry the pail of nightwater to the allotment and top up the butt. Don’t knock it before you try it with this aid my father won top viola and pansy awards and 7 gold medals on one day at the national carnation show. He won numerous awards for sweet peas and awards for chrysanthemums nationwide. So don’t knock the power of piddle!

Foliar Feeds
In the early 1920’s fine mist spray syringes became more generally available. My father was one of the pioneers developing the techniques, leading the quest for yet larger more perfect flowers and it was to this end that foliar feed was developed.

After hot sunshine leaves can be seen limp and wilting yet by next morning they are restored to full turgidity. We can give nature a gentle helping hand here. Although early morning and afternoon sun is beneficial, if we shade the plants from the full intensity of the heat of the midday sun we can prevent wilt.

A gentle mist spray directed upwards under the leaves will assist follicles to open fully during the night for maximum gas exchange, i.e. leaves expel oxygen and take up carbon dioxide. At the same time, through the leaf pores foliar feed will improve photosynthesis and growth. Do not spray either in the morning or during the heat of the day as this can cause leaf scorch, i.e. loss of photosynthesis. Wait until the cool of the evening.

Whether watering or spraying, dilute liquid feed 15-20:1, using tepid water.

(Reproduced with the permision of B O G Birmingham Organic Gardeners)