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Buyer Beware: Six Dos and Don’ts of Retrofitting an Existing Greenhouse

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Submitted by Elsewhere on 2020-Oct-01 Thu 22:21
500Foods shared this story from - DrGH Blog.

Greenhouses are a great option for indoor growers looking to reduce operating costs and take advantage of the full spectrum of sunlight to grow their crops. For field farmers who are susceptible to crop damage and loss from unpredictable weather and unwanted pests, greenhouses provide protection and consistency. Purchasing an existing greenhouse can reduce the capital investment, provide grandfather rights to water, and minimize the regulatory burden associated with new construction. However, the existing greenhouse could also require a significant investment to make it work for your crop; to update the technology and upgrade utilities; and to even demolish or remove what is non-functional or obsolete. 
The following list of Dos and Don’ts will help set you and your team up for success as you evaluate and prepare to grow in an existing greenhouse.  

1. Don't believe everything you're told

It is always really exciting to find an existing property that checks all the initial boxes. It’s the right size, the right cost, has utility hookups, and even has existing equipment that was used before to grow crops successfully.  However, depending on what crop you plan to grow, what your production targets are, and the experience of your cultivation team, the existing systems and infrastructure may not fit your specific needs. 

2. Do your due diligence

To determine if the existing greenhouse and its systems can help meet your production goals, it is always recommended to see the facility for yourself. Plan a site visit, meet with the property owner, and take your head grower and a trusted greenhouse consultant, if you can. Some of the observations you’ll want to make include:
  1. Structure: What shape is the greenhouse structure in? Is the greenhouse frame made of wood, aluminum, or steel? 
  2. Cover: Is the cover the material you want? Will it need to be replaced with something new? If the greenhouse is covered in plastic film and you want to use double polycarbonate, can the existing frame support the new cover? 
  3. Irrigation: Is the existing irrigation system reusable for your new crop? If lettuce plants were being grown in deep water culture, will that work for your new tomato or cannabis crop? 
  4. Climate Control: What condition is the existing pad-and-fan system in? Is the cooling pad calcified and eroded? Are the fans sized correctly for the new blackout system you need to install? Are the existing boilers operable and sized correctly for the heating demands of your operation? 
  5. Lighting/Shading: Are there existing supplemental lights for your new cannabis crop in Michigan? Is there an operable shading system and/or blackout curtains to manage incoming sunlight?
  6. Utilities: Where is your water coming from and what is its quality? (you may even want to request a water quality test before you visit the site) Do you have access to grid power and natural gas? Will you need a service upgrade or on-site power generation?
  7. Automation and Controls: Does the existing controls system consist of manual switches and dials? Are the sensors functional and calibrated? Is the integrated system programmed for the crop you plan to grow?
  8. Other: Is there enough storage for consumables and parts? What pests are prevalent and how were they managed (pesticides, screens, etc)?

3. Don't assume you can grow plants on Day 1

Although you may plan to grow exactly the same crop exactly the same way as the previous user, it is unlikely that you can (or will want to) move plants into the greenhouse on Day 1. During the due diligence process, not only will you identify deficient and broken equipment, you will likely also identify inefficiencies in product movement and resource utilization that could be improved to maximize productivity and profitability of your farm. Applying new technology, including the analysis, design, installation, and startup of new and existing equipment takes time, and your team will appreciate a transition period to get things right from the get-go.

4. Do plan for a transition phase to prep, modify, or repair

Now that you’ve purchased the greenhouse, the fun of moving in can really start. This transition period will require some planning and preparation to work out as many of the kinks as possible before planting the first plant. The greenhouse site will be abuzz with several activities, including cleaning and sterilizing the grow space, prepping the ground cover, servicing existing equipment, installing new equipment, purchasing consumables (nutrients, rockwool, etc.), organizing the headhouse, calibrating (or replacing) sensors, configuring the controls system, and even putting a fresh coat of paint on the walls of the office. Depending on what modifications, additions, or repairs are needed, it could take anywhere from 3 to 12 months to transition into the new greenhouse and be fully operational.

5. Don't expect the previous user to help or answer questions

Sometimes you will get lucky and the previous greenhouse grower will share their experiences of what they liked about their greenhouse and what they would have changed, if they stuck around or had the capital to invest in improvements. However, in most cases, the previous owner will be MIA and it will be up to you and the team to assess the existing systems and figure out for yourselves what you would keep and what you would change to meet your crop’s needs and production goals.

6. Do give your grower time to figure things out

Even if you’ve hired an experienced grower, unless they were growing plants in the existing greenhouse you’ve purchased, they will need time to acclimate to their new environment. Many cannabis growers got their experience indoors, where sunlight and seasonality were totally or mostly a non-issue. A greenhouse will be susceptible to the outdoors, including hourly changes in sunlight and solar radiation, seasonal changes in weather, and daily variabilities that are often unpredictable (e.g. cloud cover). If you’ve hired a grower with greenhouse experience and they grew lettuce when you’re now asking them to grow tomatoes, they will also need to adjust to new crop management strategies and targets. Most experienced growers will tell you that it takes about one year to experience all the seasons and to fine-tune the greenhouse and its systems to finally meet production goals.
When evaluating and purchasing an existing greenhouse for a new crop, it is important to ask yourself: What am I getting for my investment? Are you investing in property that is functional and appropriate for your new operation? Who will be operating the greenhouse and what is their input? Will you have to put more money in to upgrade the greenhouse and its systems than the money you saved by avoiding a new greenhouse or a new site? Answering these questions before purchasing the greenhouse will set the stage for a successful new operation.