Converting Poultry Houses into Indoor Growing Facilities

Gordon Johnson, Extension Vegetable & Fruit Specialist; gcjohn@udel.edu

Introduction

With many poultry houses being retired or unused, there has been an interest in converting these houses into indoor growing facilities, such as lighted hydroponics. Throughout the US, unused facilities such as warehouses are being converted for growing vegetables and herbs (such as leafy greens and basil). This has been made possible by the decrease in lighting cost with LED grow lights. The Cannabis industry has also adopted indoor lighted growing for production of medical marijuana. Other possibilities are bag culture of many specialty crops with lighting, and tank culture of blue-green algae (Spirulina) with lighting. There is also the potential to use facilities to produce mushrooms without supplemental lighting.

Addressing Food Safety

Because these facilities were used for poultry production there is some concern of the facilities harboring pathogens that are of concern for produce food safety and food borne illness. In most cases, the houses have been out of production for a significant period and therefore pathogen loads should be low or non-existent. The one pathogen group with ability to survive in the environment for a longer time are the Salmonella species. Pre and post testing for Salmonella is recommended (floors and surfaces). Take floor samples paying attention to any wet areas and entrance areas. Swabs should be taken from ceiling and walls.

Another issue is rodents. Rodents can also carry pathogens of concern. Active rodent infestations must be controlled prior to any conversion.

Appropriate Houses for Conversions

More modern houses that are clear span would be preferred over houses with interior posts. Houses should not have curtains. Houses should have an intact well-maintained roof with no leaks. Ceilings and walls in the house interior should be in good condition with no holes and should be well insulated. Houses should not have areas where water collects or have floors that stay wet.

Conversion Steps to Ensure Food Safety and Proper House Function

1) Poultry equipment

Much of the equipment inside of the poultry house needs to be removed. Prior to renovation, remove all feeders, brooders, and waterers and associated cables and pulleys. Determine what wiring will be kept and remove any that will not be used.

2) Floors

Poultry house floors are of concern for several reasons. During poultry production ammonium, nitrate, potassium, sodium, and other salts migrate into the floor. This results in a very caustic condition that is damaging to equipment. In addition, ammonia can be released from the floor when wetted and that can be damaging to plant health and worker safety. A third issue is the possible persistence of microbes that are of concern for produce food safety and food borne illness (Salmonella specifically).

First, remove all residual litter completely with attention paid to side walls. Then excavate the top 2-6 inches of floor (6 inches is recommended). Apply an ammonia control material at recommended rates (alum or gypsum would be examples). This eliminates ammonia release. Cover the floor area with 2-6 inches of clean fill soil, level, and pack.

Research has shown that the excavated fill can be spread onto nearby crop fields as a fertilizer. If not used immediately, stockpile and cover with a plastic tarp to avoid leaching and loss of nitrogen.

While it is not a requirement, to make a more useable work surface cover with geotextile fabric. Further coverings over the geotextile might include gravel, pavers for walkways, or sand.

3) Ceiling

Inspect the ceiling and make necessary repairs.

If the ceiling is intact and in good condition remove all loose dust, cobwebs, and other loose materials. This can be done using a commercial grade vacuum or by power washing. After removal, sanitize the ceiling with appropriate materials that have activity against pathogens (most liquid poultry house sanitizers are acceptable). Dry sanitizers are also available to reduce wetting.

Cover the ceiling with 6 mil white poly plastic, Tri-Ply (white side facing), or other white, cleanable ceiling material and attach with strapping or cleanable lath.

4) Walls, doors

Inspect walls and make necessary repairs (if the wall is in poor condition, it may have to be replaced). Check the insulation and replenish or replace where necessary.

If the wall is intact and in good condition remove all loose dust, cobwebs, and other loose materials using a commercial grade vacuum or power washer. Sanitize walls with appropriate materials that have activity against pathogens. Cover walls with 6 mil white poly plastic or other white cleanable material.

Wooden doors should be replaced with white cleanable foam or composite materials.

5) Vents, fans, and pads

The ventilation system (fans, cooling pads, vent boxes) should be thoroughly cleaned and repaired or replaced as necessary.

Vacuum, clean, and sanitize vent boxes, cables, and pulleys. Cool pad vents should be replaced with new pads and water systems should be sanitized. Fans and fan housings should be cleaned completely and then sanitized with appropriate materials

6) Heaters

Poultry house heaters are unvented and may pose a risk to plant growing. If unvented heaters are used, care should be taken to make sure they are in good working order and the ventilation system is operating to replenish air from the outside. Clean existing heaters with an appropriate method.

Heaters may also be replaced with new vented greenhouse type heaters or other alternative heating such as hot water systems.

7) Final disinfesting and testing

If possible, heat the house for 4-7 days at greater than 120 °F for the final pathogen kill step. Test the floor, ceiling, and walls for Salmonella again after conversion.

Costs

Estimates for house conversion according to University of Delaware Guidelines: 40’x550’ house

• Cost for removal of current heaters and cost for removal and disposal of all old poultry equipment $3,000
• Litter removal and cost of excavation for top 2-6” of house floor $5,000
• Cost for alum or gypsum to apply to floor after excavation $1,000
• Cost for 6” of replacement fill dirt, applying and packing $8,000
• Cost for impervious Geo textile fabric and application $4,000
• Cost for cleaning ceiling and sanitation of ceiling $3,000
• Cost for white poly for ceiling and covering ceiling $25,000
• Cost for cleaning walls, repairing walls, and covering with white poly $10,000
• Cost for new doors and vents and installation $5,000
• Cost of removal and replacement of cool cells $3,000
• Salmonella testing $2,000

Total $69,000

This cost can be reduced significantly if existing family farm labor is used to excavate and replace fill, apply geotextile, clean and disinfect where needed, cover walls, cover ceilings, and replace doors and vents.

 

 

Growing System Installation

The type of growing system will greatly influence the final cost of the installation.

Install new wiring for lighting and control systems and then install grow lights. Install appropriate plumbing and water treatment systems. Install hydroponic growing systems and associated tanks and pumps (deep water/tank, drip/bucket, or nutrient film/gutter system).

The costs will be dependent on the crop grown and the production system that is used.

One initial cost is a new electric service. Existing electric service in the poultry house will be inadequate for an indoor facility.

The poultry ventilation system and cooling system could be used but may have to be modified to have appropriate air speeds.

Hydroponic growing facility needs

Air circulation system and overhead vented unit heaters (or reuse poultry system heating and ventilation)

Environmental controls

Hydroponic NFT growing system, drip and bucket system, or tank system

Growing supplies, fertilizers, pesticides, seeds, plants

LED grow lights (will be the major cost of the system)

Total cost for growing system ~$250,000