Following on from last issue Paul Plant investigates the role of soil additives that enhance the organic garden.

Gypsum
Gypsum is a natural mineral fertiliser which is composed of Calcium (Ca) and Sulphur (S). Gypsum is frequently used to supply calcium to soils but tends not to affect the pH, although reports have indicated it can cause some soils to become more acidic with extended use over time.

Lime
Lime is a natural mineral fertiliser available in a number of forms. Two commonly available forms are ground limestone (calcium carbonate) and builder’s lime (hydrated lime, calcium hydroxide). Gardeners should only use ground limestone.

Dolomite
Dolomite is a natural mineral fertiliser composed of Calcium (Ca) and Magnesium (Mg). It is regarded as a natural limestone
source with significant magnesium content of at least 8%.

Zeolite
Zeolite is a group of natural crystalised minerals that,
when dehydrated, develop a porous structure.

Diatomite
Diatomite is made up of the fossilised shells of diatoms, single-celled (unicellular) organisms. These natural layer formations of rock are called diatomaceous earth. High in silica, the typical chemical composition of diatomaceous earth is 86% silica, 5% sodium, 3% magnesium and 2% iron.

One of the twelve permaculture principles put forward by co-founder David Holmgren essentially states that “every element should perform two or more functions and every function should be supported by many elements”. In essence this means that as gardeners we should encourage diversity in form and function thereby creating stability and resilience in our garden and food systems.

Guilds are one of the key tools that permaculture designers use as building blocks in the overall design of a garden or property, particularly with respect to fruit trees.

The end result is that an established, well-designed guild mimics nature and provides mutual support and protection for all plants involved, effectively giving us more “bang for our buck” than growing each plant in isolation, and creating a sustainable, productive garden for us to enjoy for years to come.

The ‘Queensland Blue’ is one of several large blue pumpkins grown
in northern Australia. Some of the other well known cultivars include: ‘Triamble’, ‘Queensland Grey’, ‘Beaudesert Blue’, ‘Crown’, ‘Ironbark’, ‘Bullock Heart’ and ‘Jarrahdale’. There are many more and various growers have their own special strains. These pumpkins are all selections from one species: Cucurbita maxima, one of three species from which all our pumpkins, squashes, zucchinis and marrows are derived (the other two species are C. moschata and C. pepo).

These also like a long warm growing season to produce quantities of well flavoured fruit. They thrive in warmer climates of northern Australia.

Also covered in the article:

• Growing Pumpkins
• The birds and the bees
• The fruit
• Save the seed

Most keen gardeners have a vegetable garden as well as the other
ornamental plants they like to grow and nowadays there is considerable interest in growing your own produce.

In the Top End, most ‘traditional’ vegetables are grown in the ‘winter’, the period from May to September which is the ‘dry’ season, though tropical Asian vegetables are harvested all year. For Darwin and Katherine the temperature varies between about
20ºC and 30ºC during the ‘winter’ period which makes it ideal for vegetable growing.

The Tropical Guava, a large shrub to small tree growing 3-6m in height, is native to South and Central America, Islands of the Carribean and Mexico. However, it is easily maintained at around 2m high by pruning, which is done in spring in the subtropics and twice a year in the tropics thereby producing two crops. The aim of pruning is to provide a framework of lateral branches that are thick enough to carry vigorous fruiting shoots, which in turn become laterals. As fruits are borne on new growth, pruning does not interfere with next year’s crop. Guavas can actually be hedged
or completely rejuvenated by drastic pruning.

Also covered in the article is information on superior cultivars:

• 'Northern Gold'
• 'Glom Sali'
• 'Hawaiian Pink Supreme'
• 'Mexican Cream'
• 'Giant Thai White'
• 'Sweet White Indonesian'
• 'Pear'
  

Two of our more unusual native herbs are discussed this issue. Surprisingly, they are members of the genus Eucalyptus.

Lemon Ironbark, Lemon Wardnee (Eucalyptus staigeriana)
This Eucalyptus is from the 1300mm rainfall belt between Cooktown and the Palmer River in far north Queensland, an area with seasonal dry winter months. The winter minimum temperature in the Quinkan sandstone country is around 18°C to 20°C. Some of South East Queensland’s higher areas would fit within these parameters.

E. staigeriana seems to be fairly tolerant of a variety of soil types. Growing in sandstone country, it prefers lighter, well-drained soils.

Bush Berry Herb, Strawberry Gum (Eucalyptus olida)
This species can grow in similar conditions to that of E. staigeriana, however E. olida handles the cold much better and is a lot faster growing. Its natural habitat is discontinuous with pockets around the feet of the Snowy Mountains and two more isolated pockets on the New England Tableland. It is ideal for temperate climates, can be grown in the cooler pockets of the subtropics but is not suited to the tropics.

One of the great things about keeping poultry is that it is relatively cheap.
You can start with buying “point of lay pullets”, which are hens that are due to start laying within 2-3 weeks. Another option is purchasing day old chicks. This is a much cheaper option but involves a little more work. If you have children, chicks provide you with the fun and enjoyment of watching them grow up. Remember that they will need extra care and it will be a few months before you see your first egg. Whichever way you go, make sure that pullets or chicks have been vaccinated.

Breeds of Chickens:

• Silkies
• Araucana
• Australorp
• Belgian Bantams
• Lowman Browns