Grow your own trees from seed.

Planting things is an important activity for many small farmers. Whether for revegetation, forestry, landscaping or food production, planting things can be a critical part of farm management – and a lot of fun.

In most areas of Australia there are commercial nurseries which can provide a range of plants and seedlings for various uses on the farm, and a feature of recent years has been the establishment of nurseries supplying native trees and shrubs from seed of local provenence.

Even so, there are many reasons why a small farmer might want to propagate their own plants. It can be less expensive – particularly if you need a large number of plants. Growing your own can provide flexibility – you can grow what you need as you need them, and over extended periods of time.

In the case of revegetation it can be important to use seed from locally occurring species and even from species which occur on your own property. But perhaps the most compelling reason is that it is both easy and lots of fun.

With the “broccoli box” method described below a novice horticulturalist can produce hundreds, even thousands, of seedlings without expensive equipment and with a very high chance of success. It does this because it meets the needs of seeds in the simplest possible ways. Commercial nurseries supply these needs via a range of sophisticated means, including temperature-controlled propagation houses and automated misting. You can easily provide the requirements for seed germination on a small but effective scale.

Germinating seeds: the 5 major needs.

For seeds to germinate they need to have any inhibitors to germination alleviated. This could require cold stratification (for some cold climate plants), hot water treatment or scarification (scratching the surface coat) for hard-coated seeds (such as Acacia species) or even smoke treatment for plants in which germination is triggered by fire. While seeds of most plants germinate readily, it may be worth making some enquiries of local horticulturalists or Landcare folk to check if the species you wish to grow require special treatment.

Water supply to the seed is critical. In the early stages of germination the seed needs to absorb water to commence germination. As the seed germinates and the root develops it needs to absorb more water to allow for growth. The “broccoli box” method allows an even supply of water to the seed through capillary action between the grains of sand. At the same time, the capillary action reduces the possibility of water-logging the seed.

Temperature is also critical to seed germination. While there are many variations for seeds from cold to tropical climates, most seeds will germinate in the range 25 to 30 degrees centigrade (25-30 C). A broccoli box under dappled shade in spring or autumn is likely in most parts of Australia to provide this range of temperature. In the middle of summer a fully shaded position may be needed.

Air is needed for germination of seeds. Water-logging of seeds is avoided in the broccoli box method through the use of coarse sand and a limited amount of total water.

Lastly, light is needed for germination. This may be particularly important for small seeds which naturally would be adapted to germination on or near the soil surface.

What you will need.

  • A Styrofoam broccoli box from the green grocer
  • A sheet of clear plastic – a bit bigger all round than the broccoli box
  • 2 x 4.5 litre buckets of washed, coarse river sand
  • About a litre of washed, fine sand
  • 6 seedling punnets/trays
  • 4 clouts or gyprock nails

Make your mini hothouse.

Cut the broccoli box to create a sloping face and leaving 7-10 centimetres of the wall at the bottom. Wash the box with a disinfectant (such as Dettol) and rinse well.

Fill the box with about 2.5 centimetres of clean water. Place the coarse sand in the box and smooth it roughly so that there is about 5 centimetres of sand in the box.

Cut plastic

Fill the seedling punnets/trays with coarse sand and level loosely to top of the punnet. Gently compact the surface of the sand.

Big seeds:place on surface and push until flush

Small seeds:sprinkle on surface (not too close or too many)

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