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Posted on Jul 26, 2013 in Experiments, Seeds | 0 comments

Early Summer Cropping

Early Summer Cropping

Starting spring and summer crops early will bring forward harvest dates thus extending your cropping season.

Methods listed below are suitable for any most warm season fruit and vegetables including tomatoes, capsicum, eggplant. It will also work for those seeds that should be planted direct in the garden however more care will be required when transplanting so as not to disturb the roots and they should be planted out earlier. For curcurbits (melons, cucumbers and zucchini) when they have 4 true leaves. For this reason it is best not to sow in until 4 weeks prior to intended transplant date.


  1. Sow seeds mid-late winter for transplanting early spring (September)
  2. Use a seed raising mix high organic matter with small amounts of nutrients.
  3. Keep seeds warm, provide adequate moisture and warmth for germination.
  4. Once germinated, keep sheltered from winds and cold and provide 16hrs or light/sunlight per day.
  5. Eight weeks after germination they should be ready to transplant. Pot up if conditions are not conducive to transplanting.

Seed raising mixes

Commercial sterilised seed raising mixes either soil based or soil free such as coir or peat moss.

To all the mixes below, add a sprinkle of lime to supply calcium plus a tiny amount of granular or pelletised organic slow-release fertiliser such as chicken manure, rock dust or wood ash.

  • Composted cow manure 50% and coir 50%
  • Worm castings 80% plus 20% coir plus a sprinkling of organic fertiliser
  • Compost 100% plus a 10% urine solution every watering

Sterilising soil mixes

The organisms that cause the diseaseĀ  ‘Damping off’ is present in most soils, composts and manures. To prevent this disease from killing young seedlings you can sterilise your seed mixes.

Place mix in a clear bag, spread to no more than 10cm thick. Seal and leave in the sun for a few days, turning daily. This will kill weed seeds and soil diseases. Alternatively, heating in an oven at 60C for 30 minutes.

Keeping seeds warm

In containers

  1. Take a heat retaining container such as a Styrofoam box and ensure it contains plenty of drainage holes.
  2. In the bottom place fresh grass clippings and top with your preferred seed raising mix e.g. mature compost, composted cow manure etc.
  3. Plant seeds into the seed raising mix and cover with glass.
  4. How it works: The sun as well as the decomposing grass produce heat and the glass and Styrofoam box holds it.

Credit: Jack Eagan

If your grass is weedy you could try this method:
In a large heat absorbing container such as a metal barrel, combine a large amount of grass (and/or weeds) with a handful of organic fertiliser pellets. The grass soon starts to decompose giving off heat. covered seed flats can be placed on top of the decomposing grass.

Credit: Adapted from Tony Baker’s heated trays method

Commercial heat mats can also be used but are expensive to purchase.

Warming garden soil

Tomato seeds can be sown in open ground as soon as the soil warms to about 20C. Soil can be warmed using the following methods:

  • Cover soil in clear plastic 2-3 weeks prior to sowing seeds.
  • Thick layers of fresh green or animal manure 20-30cm thick can be placed in trenches under the topsoil. The heat generated by the composting material radiates upwards, warming the soil and roots above it.

Providing Light

A warm sheltered position outside or even the screened side of a sunny window will do the job.

Grow lights can be used but are expensive to purchase.

Past seed raising experiments: Experiment 2014


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