Argosee Tunnels. Introduction. The Pros and Cons of Tunnel Greenhouses

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1 Argosee Tunnels Introduction Tunnels have always been the simplest way to change the environment in order to protect crops or grow out of the normal season and are ideal for emerging commercial operations, education and hobby growers. All of our tunnels are designed to suit AS 1170 part 2 (wind code) and site specific certified drawings are available for applications through the shires. We can produce tunnels that span 8, 6.4 and 4 metres Wide with multiple bays to get you to almost any length of tunnel that you might require. The Pros and Cons of Tunnel Greenhouses Pros: Low budget and good for starters, Very good light distribution and with diffused greenhouse film the greenhouse orientation is not as important, Good wind resistance if constructed properly, Easy and quick to build with reliable instructions, Extremely versatile with many options for managing your crops. Cons with the means to manage: Too hot in summer Can have either an internal or external thermal screen to help with the heat, Too cold in winter Tunnels with single layer covers can be colder inside than the temperature outside due to trapped low humidity that cools and becomes high humidity and condensation to Counter this it is recommended to fit twin plastic covers with inflation, internal thermal screen and if necessary heating. Loss of space at sides 8 metre tunnels have very little loss of space due to large radius. However smaller tunnels will be height restricted at the sides and usually this is the place for benches or troughs. Poor ventilation With tunnels over 20 metres in length there can be a problem with resistance to air movement especially with vining crops like Tomatoes or Cucumbers - Argosee tunnels have large end vents and wherever possible we build with a modest slope from end to end so that the hot air will rise and keep moving to the end vent.

2 Tunnel Range 8 metre polythene 6.4 metre polythene 6.4 metre Span Gutter Connected Multispan 4 metre polythene 8m Shade Tunnel Choosing the Right Tunnel for Your Purpose Hobby and Educational: 4m and 6.4m Commercial Starter: 6.4m for initial concepts Commercial: 8m x 30m tunnels are a good economical size. 6.4m multispan for larger areas with forced ventilation or roll ups all round Comparison of Tunnel Structures with 6.4m Gutter Connected Multispan. The 6.4 metre gutter connected multispan is an inexpensive large area cover with many functions: - With rain cover (left) Naturally ventilated greenhouse maximum 30 metres long and 4 spans with end vents, roll up sides and ends

3 Covering Materials Greenhouse Film: A Specialling designed film which is a very good form of covering for tunnels with the only problem being its usable life of 3 5 years after which, if it is still intact will have a very low light transmission and as the Dutch growers say 1% light loss = 1% crop loss. This film is available in large widths up to 14 metres and as a rule of thumb 8m tunnels are 12.5metres from ground to ground 6.4m tunnel is 10 metres and the 4m tunnel is 8m. The required size must allow for digging in at least 750mm on each side unless you have side rails. Strong and well proven over many years, Large space with limited columns and very versatile, Shown (left) with wet wall cooling and Thermal Screens, Easy and quick to construct, Easy to cover, Low budget, Crop loading capacity, Can be flat packed for transport, Suitable for storm water harvesting. Properties: You can get thinner or thicker film but 180 micron is a good combination of light transmission and longevity normally with a 30 month warranty. Light transmission from new is about 77% to 88% in the spectrum for PAR (photosynthetic active radiation) used by plants. Generally has an anti-drip treatment to the inside that prevents condensation from hanging on the plastic reducing light transmission and dripping on plants. 180 micron should withstand winds up to 120 km/hour before tearing or can be damaged by willy willy or cock eyed bobs. Diffusion in a greenhouse film refracts the light in many directions and creates a higher light level low in a tomato or cucumber crop and reduces tip burn on bright late spring days. There are other properties that also have an effect on some insects. Diffused Film: Price is about $2 per square metre Light transmission up to 88% year warranty. Double film with inflation is a very good way to reduce heat loss/gain using entrapped air as an insulator. Insulation value for 1 layer is 9/w/m2/C which reduces to 6w/m2/C with 2 layers and an air gap up to 300mm. There is also a range of covering materials to suit our tunnels: 180 micron Clear or Diffused Greenhouse film 1 or 2 layers. Corrugated or Triple Wall Polycarbonate (8m Tunnels only). Knitted Shade cloth of Different Colours and Shade Factors. Combinations to suit your Process and Plants. 50 mesh Insect Netting for Exclusion or Inclusion of Insects. Thermal Screening from 50% up to 75% shade. F Clean Specialised Film.

4 Specialised Greenhouse Film F Clean: This is a very expensive but long lasting film that is especially useful for any projects that require very high light transmission and that pass UV light. The film is very strong with no stretch and may require mechanical tensioning or two layers inflated. With an expected life of 25 years and used on projects such as the swimming bubble at the Beijing Olympics. Price is about $18 per square metre - Light transmission above 90% - Warranty 10 years Insulation value is the same as normal film Corrugated Polycarbonate: Structurally corrugated polycarbonate works well on tunnels and can be fitted if extra roof rails are included in the kit as it requires support every 1 metre over the structure. When fitting this material it is important to use screws that cut a hole large enough for expansion and have at least an 8mm diameter. Price is about $16 per square metre of roof surface Light transmission about 90% - 10 year warranty Insulation Value 9w/m2/C on the actual surface area The disadvantage of this material is that it has a larger surface area by nearly 50% due to the corrugations, so more heat loss and condensation at night. Triple Wall Polycarbonate: Structurally triple wall polycarbonate works well on tunnels and can be fitted if extra roof rails are included in the kit as it requires support every 1 metre over the structure. When fitting this material it is important to pre drill holes large enough for expansion that have at least an 8mm diameter and to seal both ends of the sheet to prevent ingress of water and bugs. Price is about $27 per square metre of roof surface Light transmission about 75% - Warranty 10 years Insulation Value 2.8w/m2/C Ventilation This is the most important aspect of greenhouse growing and can be the success or failure of a new project as lack of ventilation can cause overheating, high humidity and condensation. Condensation or free water is a real problem as it promotes fungal and viral infections in crops as fungal spores will grow in free water but not in high humidity and dry plants. Tunnels will ventilate end to end as long as they are erected on a minimum slope of 1% and do not exceed 30 metres for 8 metre tunnels and 20 metres for 6.4 and 4 metre. End vents on the smaller tunnels are usually operated with a rope but larger vents have a rack and pinion drive and gearbox to hold the vent position. When there is a large vegetative mass in the tunnel such as a tomato or cucumber crop ventilation rates can be improved by roll up sides or end exhaust fans. Inside view shows extent of roll up and a light shade lining to keep out moths and butterflies. The lining can be 50 mesh AV net that will also eradicate airborne thrips and aphids. Note: The lower the insulation value the lower the heat loss or gain. Shade Cloth and Nets: There are a large number of shade cloths and nets that can be used as a cover: - Knitted Shade cloth in Green, Black, Beige, White and come in different grades: Light (50% shade approx.) Medium (70% shade approx.) and Heavy (90% shade approx.). These can be made to roll up at the sides. 50 mesh AV net for exclusion or inclusion of insects which is a natural colour with 25% shade and a 50% reduction in air movement. Bird net and hail net for protection of crops. Thermal Screen external covers as static or roll up application. We are happy to help with design and work with you to suit your requirements

5 For a roll up side you will need the following parts: Side rail RHS and clamps to attach to the greenhouses steelwork with Spring Clip base screwed to it. A 1.8 metre width of a filter material such a light shade cloth or insect netting A galvanised pipe roll up tube with sufficient weight to keep the roll up material taught We generally use a woven clear material such as Hortiweave as the roll up. A hand winder gearbox with a winder post to attach to and hold the rollup in the required position. Webbing or rope to hold the material to the structure as it moves. A metal or plastic panel at the bottom as an anchor for the lining net and seal at ground level Thermal Screens Thermal screens are an essential part of tunnel growing in Australia as we have a large difference between daytime and night-time temperatures that can play havoc with tunnel conditions:- To reduce incoming heat and prevent crops from heat stress and burning. Maintain higher night temperatures when closed and reducing condensation. Reduce the volume of air for heating and cooling. We can fit screen systems to your tunnel either as an internal or external screen as a manual, push/pull or cable drive system, with or without automation. A full range of screen parts for manual, push/pull and cable systems and screens is available. LPE-12 65% CLOSED SHADE LA-13 75% CLOSED SHADE LA-12S 65% OPEN SHADE LA-13SF 75% EXT SHADE LA-11S 50% OPEN SHADE LA-13S 75% OPEN SHADE LPE-1 ENERGY LA-13SF 65% EXT SHADE LA-11 50% CLOSED SHADE LA-13SF 75% EXT SHADE

6 Attaching Greenhouse Film Spring Clip is by far the simplest and most effective method of attaching Greenhouse Films and cloths to tunnel structures. The Aluminium base is attached to the structure using self drilling Tek screws at about 250mm spacings The spring is wound into the channel to retain the covering material. Multiple layers can be retained by one spring or 2 springs can be used for separate covers. Tunnels in exposed areas should have 2 springs holding the main cover. The wet wall is built into one end of the tunnel and the required fans in the other end with all of the incoming air passing through the wall. The tunnel must be sealed along the sides and the ends to prevent air short circuiting. The pictures (left) are of a typical wet wall and fan system in an 8 metre tunnel. The fans are generally slow speed belt driven and reasonably quiet with stainless steel blades and automatic louvres. Available as single or 3 phase. We have a range of fans to suit any size of cooling job and we can offer inexpensive control systems along with installation from new or retrofit. Wet wall systems can be closed off in winter using a roll up blind (above) Insect netting can be used to reduce dust and insects entering the greenhouse and to keep the Celldeck pads clean (left). It is essential with this system to seal the bottom of sides and ends. Cooling Tunnels and Multispans We have a simple and inexpensive solution for effective cooling and enhancing the humidity of tunnels large and small using a wet wall and fans. Note: This is very effective in regions that have dry heat and less effective in hot areas with higher humidity. The chart below will give you some idea of the resultant cooling that you could expect. This type of cooling requires a good clean water supply that is circulated from a tank through the wall and back to the tank. It also requires an air speed of about 1.25 metres per second entering the tunnel through the wet wall where it picks up the water and evaporation takes place, causing cooling.

7 Benches We produce a large range of both fixed and rolling benches with a number of bench top options; such as the new plastic tops that are becoming popular as they have a flat smooth top for good plant handling and hygiene. They can be used on both fixed and rolling benches. With Rolling Benches you can maximise the use of the floor area up to 80% Benches with electric mat heating Low level rolling benches for tall plants. Flood and drain benches Hydroponic troughs Low budget fixed benches Computers and Controls We can offer these comprehensive greenhouse control systems that are very reasonably priced and extremely user friendly. Call for more information about our Greenhouse Computers Single and up to 8 Zones Simple Low Cost Plug in Temperature and Humidity Controllers. All with Installation Assistance and Support We are happy to help in design to suit your requirements.

8 Argosee is very flexible in its designs and will customise to suit most requirements, we are happy to help you plan your project. Other Products: Tunnel Greenhouses from 4 metre to 8 metre span - kit form or erected, supplied in flat pack metre span trussed greenhouses or gutter connected multi span metre span trussed greenhouses or gutter connected multi span. Custom designed permanent greenhouses up to PC2 QC2 standard. Multiwall polycarbonate. Plexiglass 16mm Alltop and 8mm Resist. Argosee Aluminium Glazing System for Plexiglass and Polycarbonate. Full range of Lauren Thermal Screens. Wadsworth Greenhouse Computers. Evaporative Cooling Wet Walls and slow speed Exhaust Fans. Heat pump cooling and heating. F Clean Films. Polythene greenhouse films. Humidifiers Full range of plate fans 450mm up to 600mm. 50 mesh (260 micron) Thrips net 3.7 metre wide Shade Cloth, Bird nets, Hail nets and fixing systems Services: Greenhouse installation, covering, re-covering, screen systems, wet wall systems, control systems. Retrofit of all products. Contact us Contact: Andy Sadler or Colin Rea andy@argosee.com.au colin@argosee.com.au Mobile: Andy Colin Web site: Address: 6 Laurence Road, Walliston, WA 6076