Maintaining Ecobed Productivity.

Latest Update 8th March 2018.

Most organic gardeners seem to spend a lot of time refining their soil conditions using (organically approved) amendments.  I have formed the view, influenced by Dr Elaine Ingham of Soil Foodweb fame, that most soils in the world contain all the minerals plants will ever need.  These minerals are locked up in the soil's rock particles and don't appear in soil tests which measure only soluble mineral content.

I also have the view that a soil full of beneficial microorganisms and their predators are capable of extracting these minerals as and when the plants need them in return for photosynthesised sugars and other energy foods produced by the plants.  Check out my blogpage explaining the Soil Foodweb for more details.

This article is linked to my Growing Organic Vegetables blog, and provides support for those readers who wish to grow vegetables in Ecobeds.  It is set in a warm temperate climate, and will need to be adapted for other climatic conditions.

Soil Preparation.
To maintain a well structured healthy soil, beneficial soil microorganisms need to be fed regularly.  Although plants provide this food in their root zone, control of soil structure, soil pests and soil fertility outside the plants' root zones depend on a high organic material content in the soil.  So I take the following measures to ensure this is always the case .
  • Every time vegetables are harvested in my Ecobeds the plant debris and old mulch is removed from the soil's surface.  (This valuable organic waste is stored for use in the next compost making process).
  • A 60mm layer of fresh homemade compost is then applied as a dressing on top of the soil, and to ensure it stays moist, it's covered with a 50mm layer of fresh straw mulch.
  • Soil microbes feeding on this compost flourish in these conditions and are ready when required to set up mutually beneficial relationships with the next crop.
  • To help maintain high fertility and a healthy soil food web in my Ecobeds, a weekly drench of compost extract is applied to the soil.  I make up a 60 litre batch of diluted extract (4 to1 rainwater to extract) each week and water it in with a watering can.
Plant Foliage
  • All the plants in my garden get a regular monthly foliar spray of aerated compost tea.  It's full of beneficial microbes and covers new and old growth with them.
  • Plant foliage is strengthened by a coating of these beneficial microbes, which bond themselves to the plant's leaves and form a glossy barrier to pests and diseases.
  • These microbes also fix nitrogen which is used by the plants in return for energy food exudates delivered by the plants through their leaves.
Managing Sunshine
  • Growing crops too close together limits their access to sunlight for photosynthesis and reduces their potential size and vigour.  It's important to keep in mind the full grown size of the plant before allocating space in which to grow it.
  • You can of course plant some crops more densely than usual.  These crops can be thinned as they grow and the thinnings are used for food (baby carrots are delicious).  The remaining plants find themselves free to grow to full size expanding into the freed up space left by the thinnings.
  • You can also use fast growing "catch crops" in tight spaces between larger slow growing crops.  By the time the main crop begins to shade the catch crop, it is ready to be harvested, and the main crop then fills the vacated space.
  • Some plants like cabbage and lettuce, are best grown in winter because fierce summer sun wilts them and causes them to "bolt" to seed.  However, when I grow them in summer I use exclusion netting with a 20% shade factor to take the edge off the sun and protect them against Cabbage White Butterfly larva.  When temperatures exceed 35C, I add a temporary layer of 75% shadecloth.
  • In the same way as gardeners set out their herbaceous borders with tall plants at the back and small ones at the front, so should vegetables be arranged in an Ecobed.
Managing Water resources.
  • Water consumption by plants depends on their size and rate of growth, but in conventional gardens a lot of extra water is lost due to evaporation and drainage to the subsoil.  Ecobeds are designed to dramatically reduce this loss.  
  • There is no water loss to the subsoil in an Ecobed, but persistent flooding rain drains readily through the overflow pipe when the bed's capacity to absorb water in its soil and store water in its tank has been exceeded.
  • The combined effect of a very absorbent soil and a generous layer of mulch virtually eliminates evaporation even in very hot weather.
  • I use rainwater in my Ecobeds almost exclusively, because treated tap water tends to accumulate unwanted chemical residues in the soil.
  • My combined rainwater storage capacity (including Ecobed water tanks) is about 7500 litres, and even in very dry summers this is usually enough to get me through.
  • To get the best out of my water storage capacity, I fill Ecobed water tanks when rain is expected.  This leaves space in my rainwater tanks to capture more rain off my roof.
  • I used 2000 litres of filtered mains water to get me out of trouble in 2016/2017.  Its a damage limitation strategy to be used only in an emergency.  The worst of the nasty chemicals are removed using a domestic water filtration system, but it is not ideal, and I would have to consider shutting down the beds for a while in serious drought conditions.
  • I haven't had to do this yet, but in the event of a drought, I would strip the Ecobeds of plants before they ran out of water completely, and I would cover them with extra mulch and a layer of shade cloth to minimise evaporation.  This measure would hopefully preserve the living organisms in the bed until it rained, or until untreated water could be obtained.