Sunday, 1 September 2013

September 2013.

Its the first day of spring in Melbourne and its warm and sunny.

August was very windy, and the purpose of the shadecloth in the above picture was to slow the wind down a bit to protect my peas, which are quite tall.  I just tied a bit of string round the broad beans to stop them blowing over.

Between the rows of peas I planted my first 3 comfrey plants.  They are planted over the gap between the water tanks in this triple tank inground Ecobed.  The comfrey will use its deep roots to take up essential micronutrients from the subsoil.  

I will harvest leaves from the comfrey to be used as worm food.  The worms and microorganisms will break down the comfrey leaves and distribute the micronutrients in the Ecobeds soil for use by other plants.

All this presupposes the comfrey will overcome the temptation to raid the water tanks on each side rather than push its tap root down between them to the subsoil. 

We have had quite a few pickings of baby carrots from this bed, and there will be quite a few more before we leave the maincrop to mature.  We have also enjoyed our first leeks of the season, and a very tasty celeriac which we added to a home made vegetable soup.

The onions at the front of the bed have grown very slowly in the cooler weather, but now that it's spring we will see much faster growth.  Meanwhile the beetroot and garlic are growing very well, and I couldn't be happier with the way this heavy framed Ecobed is performing.

Its going to be quite a challenge to decide which version of the Ecobed I will put in place of the conventional bed (above) after I have harvested the cop of potatoes just planted.

Neither the heavy framed Ecobed nor the Inground Ecobed have required a refill of water since Autumn.  They are both performing well with healthy crops and no pests or diseases so far detected.

The decision will come down to water consumption.  If I feel the inground Ecobed is significantly thirstier than the heavy framed Ecobed, I will go for the latter.  If not, I will use a modified version of the inground Ecobed.

These are the pros and cons of the two designs as I see it:-

Heavy Framed Ecobed.
  • Raised garden beds like these are easy to manage.  You don't need to get down on your knees to service the bed (soil prep, planting, harvesting etc), and you don't need to dig it.
  • Heavy framed Ecobeds don't loose water to the subsoil.
  • However, they don't have access to the surrounding soil or subsoil and this can (potentially) create an imbalance of soil microbes and microfauna in the bed, and lead to disease and micronutrient deficiencies.  
  • A well fed built-in worm farm helps maintain the balance, and regular applications of compost adds to the biodiversity.
  • Worms can't wander off,  but passing worms can't visit either. 
Inground Ecobed. 
  • So far I have had no problem retaining and growing the population of composting and earthworms in the inground Ecobed. 
  • There is good access to the soil surrounding the bed and to the subsoil with its wider availability of microorganisms and micronutrients.
  • It remains to be seen whether dispersion of soil moisture from soil above the water tank to soil below the bed will be significant.
  • Inground Ecobeds have smaller water tank capacities than heavy framed Ecobeds (for the same growing area).  They will take less time to refill but will need more frequent refills.
  • Build costs are significantly lower for inground Ecobeds, especially if you dispense with retaining walls.