Nutrition in Tasmanian soils

Millions of years of heavy winter rains have leached most Tasmanian soils into chemical imbalance that lowers the nutrional qualities of its vegetation. The overall amount of plant nutrients Tasmanian soils contain is low, because most of the minerals that most of our soils started out with have, over time, been washed out.

This leeching is unfortunately not uniform. It removes the more soluable nutrients readily. Unfortunately for us, the minerals that make plants nutritous- calcium, magnesium and phosphorus- are the ones that are leeched out more easily, whilst the one mineral that, in excess, provokes plants to produce nutritionless calories-potassium- tends to remain in fairly large quantities. Most Tasmanian home vegetable gardeners live on and eat from highly-leeched soil.

Chemically unbalanced and chemically deficient soils grow plants of low nutritional content. Nutrient-poor grasses fed to livestock then produce nutritionally unbalanced manure of rather low quality. Tasmanian manures are heavy in potassium. Plants concentrate potassium in the leaves and fleshy parts, storing the nitrogen, phosphorus, calcium and magnesium in their seeds.

I use only a chemically balanced organic fertiliser and make compost from all vegetable scraps and other green matter from our garden.

If you build a compost heap of plant material that is imbalanced in favour of potassium, you end up concentrating the problem. It is really important therefore that the fertilser used in your vegie garden is of a balanced formula.

I use a combination of complete organic fertiliser ( made to Steve Solomon's formula) along with a fine layer of compost made from balanced vegetable and plant material.

To make compost:

I use an area of 3 metres x 1 metre deep, comprising 3 bins for the processing of compost.

Bin1 contains the vegetable material from the vegie garden and from our compost bucket in the kitchen. This commences to rot down, but to ensure it contains a balance of nutrients and rots down at the correct temperature, destroying most of the weed seeds.


I layer it in Bin 2 using layers of approx 15cm of vegetable material and compost from Bin 3 which contains the finished compost ready for use. Notice that I use a length if poly sewer pipe about 1 metre high that has been drilled with holes to allow the air to circulate in the heap.


I place the pipe in the middle of Bin 2 and build the pile around it. A thorugh wetting and a good addition of blood & bone to provide the nitrogen necessary for rapid breakdown starts the heap breaking down.


I turn this about every month with a garden fork.

By the spring of the next season it is ready for use in the garden. I seive the compost through the spring base of a baby's cot to remove any large sticks and clumps of vegetation that have not been thoroughly broken down.

A Layer of 2 cm spread over the surface of the newly formed bed along with 4 litres of COF for each 10 square metres of garden bed provides a great start for the new seedlings. I lightly work this into the top 10 cm of soil with a rake and then sow the seedlings. I then water them in with a comfrey tea solution, and the seedlings never look back. Side dressings of COF are given every 3-4 weeks until the plants no longer respond to further additions.

I am confident that the nutrition of the vegetables we eat is excellent and well balanced.

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