Season Extension
COCOON TUNNELS
'Shoulder season extension tunnels for regenerative soil systems.'
(Portable hothouses, Cocoon tunnels, Caterpillar tunnels, Season extension tunnels)
Cocoon Tunnels as they are often referred have been around for a few decades, finding a place in the fringes of small growers systems in varying forms of DYI or more often than not, clumsy kit forms. This earlier tangent has completely shifted to suit the needs of professional micro-farmers.
More recently the groundswell in soil focused micro-farming has led to rethinking the need for good quality, professional use Cocoon Tunnels that are economically justifiable.
Crop rotation is of critical importance for successfully regenerating living soil, by using a modular/standardised bed block system we can incorporate standardised season extension tunnels into the design. This allows a number of benefits to the regenerative farmer.
Timed cover of crop/bed block for effective season extension.
Timed removal of early season cover, shading mid summer, late season cover.
Increased unheated hot house area for specialty hybrids, eggplant, tomato, capsicum and cucumbers to name a few.
regenerative soil management.
Greater versalitility in planning, ability to move across zones or blocks.
Seasonal adaptability, a variety of different grade covers can be used, shade cloth or poly films.
Typical design
Span; the Cocoon Tunnel kits from ActiveVista span four permabeds, at 4.65 metres dia
Height; the steel hoops eight metre x 35mm arc peaks at 2.75m (Pro version) and is semi circular in gradient
Length between end hoops, ActiveVista’s Cocoon Tunnels usual lengths are 15 metres (50 foot) or 30 metres (100 foot) other length options are available.
End wall 'triangular tie off' lengths, these can be modified slightly and range from 3 to 4 metres from the last hoop to a star picket, angled backward and centered perpendicular to the end hoop. You need spare area at the bed ends totaling 6 to 8 metres overall, this can be dealt with either by losing a bit of end bed while still growing within the tapered area or extending out over end paths.
Side walls, typically these can be lifted and will allow good air flow across both sides length-ways using side curtain hooks.
Semi-permanent stays, the hoops sit over 100cm x 16mm rebar inserted about 400 mm into the earth. A 'Jack Jaw' star picket remover will make easy removal of these, or a refashioned diamond jack.
Centre purlin, in the basic and effective form the purlin is a nylon strap, tied off to the star pickets at either end. Snow protection can be added by using the static tube steel purlin option.
Pros and cons
If not set up correctly they will be problematic
Can be set up quickly by few people on a still day
Although sourcing your own may save you dollars, it may take a whole lot more time and headspace away from the matter at hand, growing and selling the food
It may be possible to DYI with the some easily sourced affordable parts such as a hoop bender, rope, carabiners, purlin strap, 150um film, rebar, again you will need to cut a bunch to length of about 1000mm
There is a variety of Cocoon Tunnel options available, from making your own using sourced components to buying a kit.