So as you can imagine, David has spent a lot of years learning how to make his soil sing, and last month he shared some of his secrets with us. For many years now he has been using Steve Solomon's Complete Organic Fertiliser on his seed trial beds. Steve Solomon is a US garden writer who originally wrote about Gardening West of the Cascades, then moved to Tasmania, where he now gardens in very similar conditions to those west of the Cascades in the US, so that is very many decades of very detailed study and observation of what works in our area of very geologically old soils with high rainfall. Basically what happens is that the few nutrients make it into our old, tired soil get washed away every winter. Think about what happens when you put fertiliser with a lot of nitrogen and phosphorous around a native plant. It dies, or gets very ill. It has evolved over millenia to survive on trace amounts of nutrients, and an overload sends it into shock. This is an indication of how very unsuitable our soils are to grow vegetables, which have been bred to require unnaturally large amounts of nitrogen, phosphorous, and all sorts of other mineral goodies.
I have two of Steve Solomon's books on my shelf - Gardening South of Australia, a self-published volume with very detailed instructions on how to grow just about every vegetable in our climate, and The Intelligent Gardener: Growing Nutrient Dense Foods, which is the most fiendishly difficult gardening book I have ever read. It contains maths and formulas and hard words. Aargh! But luckily the first half is pretty straightforward. It tells the story of Solomon and his family, happily attempting hippy back-to-the-land self-sufficiency in Oregon. Which they did. Hurrah! BUT then the family's health started to deteriorate. Solomon started losing teeth.. what could be wrong? They were eating a completely healthy organic diet, but not thriving. Then they moved to Fiji, and ate conventionally grown and treated food at the local markets, and their health improved immediately. What was going on? Solomon traced the solution to their new-found health and vitality to the local soils - volcanic, highly mineralised basalt. And on returning to Oregon and turning a critical eye to the composition of the soil there, realised how impoverished it was. No amount of home-made compost and organic mulches were going to solve this problem, only the regular addition of minerals to supplement and replace what was missing.
It was then that Solomon started to develop the Complete Organic Fertiliser that thousands of gardeners now use to supplement their naturally sad soil. Now, when you think of Tasmania you think of lush green pastures and glorious gardens bursting with roses and beautiful vegetables. And yes, this happens. Tasmanian soils are quite high in potassium, which make our plants green and lush, but unfortunately, also quite nutrient deficient. One of the most well-known nutrient deficiencies in Tasmanian soils is iodine. Many older Tasmanians who lived self-sufficient lives on little properties out in the forests, suffered from thyroid problems and goitres. Well, apparently iodine is just the beginning. Our poor old soils can do with a whole lot more help, which is where Solomon's formula for healthy soil comes in.
To be honest, I have never made up any Complete Organic Fertiliser, because some of its ingredients aren't actually available at the local garden centre, and that has been a step too far for me.. I generally add all the ingredients that I do have on hand and hope for the best (yes, I am very scientific) but now I know that David makes it up and sells it, I will certainly be using it.
David also introduced us to biochar. Tasmanian local Frank Strie has introduced it to Tasmanian gardeners and farmers as a way to improve soil structure and sequester carbon. It is a form of charcoal which has been burned in a particular way, which was too highly technical for me to grasp - however it can also be made very simply, with very simple equipment, almost anywhere, which makes it an amendment easily available to anyone who can grasp the technique (clearly that does not include me). It was originally used to improve the fertility of the nutritionally poor soils of the Amazon basin thousands of years ago, and the technique has been recently revived and popularised.
The greatest benefit of biochar to the home gardener is its porous structure, which simultaneously helps to retain water and water soluble nutrients, which is why it is particularly useful in an area of high rainfall, such as ours, when often the nutrients we add to our gardens leach away as fast as we can replace them. Biochar also appears to provide an ideal habitat for beneficial soil micro-organisms and increases nutrient availability to plants.
David did some small field trials using biochar in 2013/2014, and if you scroll down to the bottom of this newsletter you can see the results - the plants grown using a bio-char amendment were bigger, brighter and heavier than their control cousins.
For an excellent summary of all of the above, as well as some excellent links, here is David's 2013 newsletter where he discusses soil health.
Taking advantage of a temporary lull as we were all happily quaffing David's very nice home brew, Michelle showed us a jar of lemon curd she had made - except it wasn't lemon curd, but an excellent lemon cleaner and degreaser which she had whipped up in her Thermomix. The recipe is here, and Michelle uses it to clean her kitchen benches and add to a sink of soapy water to clean particularly greasy dishes. Apparently it is just as useful in the bathroom. I am determined to work out a version for those of us who somehow manage to exist without a Thermomix, and I will of course share how that goes.. although if any of you were to give it a go before I get around to it (highly likely) I would love to hear how you did it:)
Again, a marvellous way to spend a cold Winter's evening, with good friends, excellent conversation and new ideas...