Cravo Retractable Roof Production System (RRPS)™


The ability of retractable roof greenhouses to increase yields by optimising the growing environment and protect crops from excessive cold, heat, rain, hail and wind allows a grower to modify where they grow and how large of a production facility they need to meet their customer demands.

This provides growers the option to improve their balance sheet by lowering their overall investment by lowering land acquisition costs and reducing the overall investment on the greenhouse.

Features:
  • UV and infrared blocking roof coverage
  • Dropdown sidewalls
  • Adjustable roofing synchronized with drive systems
  • A-frame, X-frame and flat roof options

The World Leader in Retractable Roof Greenhouses/Shadehouses

www.cravo.com

“We are subjected to wild weather at times however with the Cravo screens we know our crops are protected all year round which gives us peace of mind”

Rob Pohlman – Pohlman’s Nursery

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The higher yields in a retractable roof greenhouse, allows growers to build fewer hectares of houses while still maintaining the same overall yield. Growers can also reduce the number of growing locations. For growers wanting to supply year round, the retractable roof greenhouses can frequently reduce the number of farm locations that would be required to ensure a constant supply year round.
Fruit quality can be improved compared to those grown in the open field or a conventional greenhouse or shade house since the roof can be closed during adverse conditions to prevent the blemishes which occur in the open field. Retracting the roof during ideal outdoor conditions help produce fruit that is larger, has a higher brix and is firmer than that grown under a stationary roof covering. Tomatoes grown in a retractable roof have proven to have a longer shelf life and have the appearance of a greenhouse tomato but are sliceable like a field tomato.
Costs to grade the land could be reduced since certain retractable roof greenhouse designs allow the greenhouse to follow gentle changes in the slope of the land. Grading costs can also be reduced if the crops are going to be grown in the ground since grades are not as critical compared to crops grown hydroponically.

Costs for power supply, backup power generation and electrical hook up of motors can be minimized since few motors are required to power the roofs. (One motor can power up to 0.5 hectare of an A frame style roof and 1 hectare of flat roof). The retractable roofs also allow you to build in warmer climate where heating systems will not be required.

Finally, it may not be necessary to install horizontal airflow fans to circulate the air since opening the walls and roofs allows the wind to circulate the air more effectively and economically than horizontal airflow fans. However, if the greenhouse roof is closed for long periods of time during the winter, then horizontal airflow fans may still be beneficial.

Retractable roof greenhouse can:

  • Allow growers to increase plant density due to the higher light levels and better control over humidity. Also, plant density can be frequently increased by around 12% in the retractable roof compared to a tunnel due to the greater head clearance and distance between post lines.
  • Increase the yield per plant due to the improved growing environment
  • Extend the growing season since crops can be protected from the winter cold and the summer heat
  • Potentially allow growers to increase the number of plantings to target the shoulder seasons
Growers of outdoor plants have experienced up to 50% reductions in water usage during the summer simply by closing the greenhouse roof 85% during hot conditions. When factoring in the increased yields, the water usage per kilo of crops harvested can be up to 85% less than that of the open field. In addition, water usage can be further reduced by retracting the roof during rainfall to

naturally irrigate your crops using rain that is free and has a low PH and salinity. The rain can also be used to clean off the leaves and help leach salt out of the soil media.

Supply produce when the prices are highest

The ability to open and close the roof provides growers with the ability to speed up or slow down production to allow the managers to time their peak production to the window when they can realize the highest prices. The best prices could be during the winter, being the first to market in the spring, being able to supply good quality through the heat of summer, or being able to supply product in the Autumn after the cold weather has limited the field production. It all depends on your crop and the market that you are competing in.

Reduce fertiliser usage

Reductions in fertiliser usage or improvements in fertiliser usage should be achieved regardless of whether your crops are normally grown outside or in a greenhouse. Fertiliser usage on outdoor crops can be improved since the roof can be closed during rainfall to prevent leaching of fertilisers. When compared to crops grown in traditional greenhouses, fertiliser application rates in retractable roofs can usually be lowered since retracting the roof increases transpiration levels to normal levels allowing plants to more easily absorb and distribute the nutrients that are available to the root system.

Reduce the risk of catastrophic loss

Retractable roof greenhouses can reduce the risk of catastrophic loss to the owner due to:

  • Crop loss due to a major disease outbreak since plants grown in a retractable roof tend to be naturally healthier and conditions inside are generally not conducive to insect and disease reproduction.
  • Crop loss resulting from losing a roof due to the wind since Cravo retractable roofs have never blown off even during cyclones with wind speeds up to 200kph (130mph).
  • Structural damage during extreme weather conditions since the roof and walls can be automatically retracted in minutes.
  • Fire, since the greenhouse roofs can be retracted during a fire which will limit the spread of fire.
Reduce or eliminate chemical fungicides, pesticides and growth regulators

The frequency of chemical usage can be significantly reduced when growing in a retractable roof greenhouse due to the improved growing conditions, increased plant health and reduced insect reproduction making it easier to utilize IPM protocols. If chemicals are required, the volume of chemicals applied in a retractable roof can be reduced compared to that in the open field by closing the roof and walls during the application to prevent wind drift. Growers using retractable roof greenhouses have experienced a:

  • 50%-100% reduction in fungicide usage.
  • 50%-100% reduction in growth regulator usage.
  • 10% -100% reduction in pesticide usage.
  • 50%-100% reductions in herbicide usage.

When calculating the total savings in reducing chemical usage, one must consider that in the retractable roof:

  • Soap and garlic is frequently used for insect control.
  • There is a reduced cost to purchase and apply the chemicals.
  • There is a potential reduction in labour downtime due to re entry regulations.
  • There is an increased life of the roof coverings since many chemicals used in greenhouses are harmful to polyethylene film coverings.
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