Maintain Healthy Plants.

Latest Update 25th January 2021.

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 believe 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 plants.  Check out my blogpage explaining the Soil Foodweb for more details.

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

Soil Preparation and Maintenance.
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 plant 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 .

• In early Winter, I add a 60mm layer of homemade compost to the vegetable growing beds after removing spent mulch and plant debris from the soil.  This valuable organic waste is stored (dry) for use in the next compost making process.
• Every time vegetables are harvested in my vegie beds I replace them with new seedlings.  A planting hole is made as close to the previous plants remnant root mass as possible and a large handful of homemade compost used to fill the hole.  Using a large dibber, I make a hole in the compost and the seedling is planted in it.
• To ensure the soil surrounding the new plant stays moist, I replace old mulch with fresh straw mulch.
• Its important to ensure soil is not exposed to the elements especially in summer when soils quickly dry out and the microbiology is compromised.  I take care to minimise soil disturbance during harvesting and replanting to ensure, as much as possible, business as usual in the plant's root zone.
• To help maintain high fertility and a healthy soil food web in my vegie beds, I regularly apply a drench of compost extract.

Worms are invaluable builders of soil structure and help provide important plant nutrients when feeding on bacteria in the plants' root zones.  Their castes provide plant available, nutrient dense food, and they need to be encourage to live and multiply in the soil.  To maintain the important soil structure, I avoid disturbing the soil as much as possible, and follow Charles Dowding's excellent example of no-dig gardening.

Because Ecobed soils are isolated from surrounding soils, positive intervention is needed to maintain a healthy worm population.  My worms are well fed with regular applications of microbe rich compost to the soil.  I also maintain built-in feeding points where worm food is supplied from our kitchen, and where the worms seem to prefer to lay their eggs.  To help maintain worm diversity, healthy worms found elsewhere in my garden are transfered to the Ecobeds from time to time.

This works best when I use these mini worm farms as a worm entry point to each bed.

They provide a protected environment, rich in raw organic waste from the kitchen, to help the worms recover and breed and eventually migrate into other parts of the bed.  The casts they leave behind when the farms are relocated (periodically) are excellent sources of plant nutrition.

Plant Foliage

• My Ecobed plants are sprayed with aerated compost tea several times a year, largely aimed at coating new growth with beneficial microbes and plant nutrients to protect them from foliar pests, which are particularly active in spring, and enhance plant growth.
• The beneficial bacteria in the compost tea bond themselves in huge numbers to the plant's foliage and form a glossy barrier to pests and diseases.
• Some of these microbes are nitrogen fixing bacterial, who exchanges this nitrogen in plant available form, in return for energy food exuded by the plant's leaves.

Managing Sunshine

• Growing clusters of some crops in small groups is an excellent way to improve productivity.  I grow, onions, beetroot, radish and turnips this way to good effect.  Good organic soil is soft enough to yield to this treatment quite well, and the plants seem to benefit from sharing the intensified microbial activity in their shared root zone.
• Larger plants grown too close together compete for sunlight for photosynthesis and their potential size and vigour can be compromised.  It's important to keep in mind the full grown size of larger plants before allocating space for them to grow in.
• 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 behind.
• You can 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 the warmer months, I use exclusion netting with a 20% shade factor to take the edge off the sun and protect them against Cabbage White Butterfly larva.  In very hot, especially windy weather I fit 75% shadecloth on my frames to further reduce harsh sunshine.
• 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 garden beds.

Managing Water resources.

• Water consumption by plants depends on their size and rate of growth, but in conventional gardens where overhead watering is the norm, a lot of water is lost due to evaporation and runoff.
• In my garden, where the soil is biologically active with a high carbon content, water is quickly absorbed into microbial aggregate structures and held there until the plants need it.  In my drip irrigated beds, where I grow most of my edible perennial plants, root penetration goes deep into the ground and this water holding capacity is greatly increased.  
• Raised Ecobeds are designed to dramatically reduce water loss by storing it in their subsoil tanks, and avoid flooding by draining surplus water from the soil through an overflow pipe.  
• The combined effect of a very absorbent soil and a generous layer of mulch virtually eliminates evaporation in all my garden beds, 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 which threaten the health of  beneficial microbes and other creatures.
• I use mains water in my drip irrigated beds, and although less than ideal, it seems to have little impact on the soil biology.  I understand that humus, a vital component of well made compost, locks up soluble nutrients like chlorine and fluorine (present in tap water) in an insoluble form which can't interfere with the soil's microbiology.  Surplus water generated by flooding rain escapes to the subsoil beyond the root zone of most plants. 
• 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 more space in my rainwater tanks to capture run off from 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 their soil with extra compost and straw mulch and a layer of horticultural fleece to minimise evaporation.  This measure would hopefully preserve the living organisms in the bed until it rained, or until untreated water could be obtained.