Important Tips for Designing a Hydroponic Production Facility

Exclusives from Urban Ag News

Why do you keep saying buffer capacity?

For anyone that has called me to discuss the design of their new vertical farm or greenhouse, they have probably grown quickly tired of me using the term buffer capacity.  But, of everything I have learned over the past 25 years, the understanding of “buffer capacity” might possibly be the most important.  It makes your production system easier to manage, more predictable and more stable.  All traits that can be found in all successful farming and commercial horticulture production facilities.  (You might remember my recent article on simplicity, well this goes right back to that.)

Let’s start by agreeing that I am not properly using the term buffer capacity which is normally defined as the moles of an acid or base necessary to change the pH of a solution by 1, divided by the pH change and the volume of buffer in liters; it is a unitless number.  A buffer resists changes in pH due to the addition of an acid or base though consumption of the buffer.

Now let us focus on how we can manipulate that definition to fit the needs of designing a greenhouse or an indoor farm.  When referring to buffer capacity in our production environment we are referring to our system’s ability to keep key elements (temperature, humidity, wind, nutrients, light, CO2, oxygen, water) from fluctuating unless we as the grower determine that we want it to and have the ability to manipulate these key variables while keeping the others in balance.

The ability to keep key elements from fluctuating unless the grower determines that the variables should be adjusted to produce a crop response.  Adjustments should be met with the abilities to keep all other elements in balance.

For this article I am going to use (3) examples of how designing “buffer capacity” into your farm  will lead to better production and more consistency.

Greenhouse Structure.

For those starting to investigate different greenhouse types and designs or for those that have already gone through the process, I think we can all agree that the choices are limitless,  and for the most part the look of the greenhouse has not changed much of the years with one major exception.  They have gotten much taller.  Taller greenhouses provide a more uniform, stable and ultimately superior growing environment for the crop. During hot weather (as an example), the additional  space creates a buffer that avoids trapping heat and humid air around the plants.

Water holding tanks and nutrient solutions reservoirs

For beginning growers this is the area where the right decisions might provide the biggest advantages.  Experienced growers may choose to size their systems differently depending on their budget, crop and space but one thing is for sure, they will make sure that they have ample water availability as well as on demand storage to respond to changing crop needs.

Larger tanks and reservoirs (as compared to the amount of plants in the system) have a considerable buffer before they will run out or need to be dumped.  The most obvious benefit is that of ensuring the tanks don’t run dry and cause extensive damage to the pump(s) or loss of crops and production.  The most important benefit might be a properly sized system’s ability to keep the nutrient solution from having big erratic swings in EC and pH.

Substrates.

Hydroponic substrates provide an (additional) reservoir for water, a place for plants to take up nutrients, an area for the plant to develop a sufficient root system as well as location for gaseous exchanges.  A good grower will consider all the other decisions that he or she has made in building the greenhouse and designing the irrigation system then decide how much buffer capacity their substrate needs to provide.  If the buffer capacity of the irrigation system is limited, the grower may choose to use more substrate with a higher water holding capacity so the total system is more durable on hot summer days.  If the grower has a tremendous amount of confidence in their access to water, the responsiveness of their irrigation system and their ability to fix the system if they have problems then the grower might choose a substrate that they can steer thereby providing them more control in the greenhouse.

Growers should always choose a properly sized and engineered system.  The reality is that the budget will drive many of the growers’ decisions.  Understanding buffer capacity in the system will allow growers to get the most out of their investment while still focusing on consistent and uniformed crop production.

To continue the conversation, email us and schedule some time with either Chris Higgins or our newest grower consultant Tyler Baras (aka The Farmer Tyler.)

Next article.  Can indoor farming be profitable?.  Simple answer: of course.  Complexed answer it all depends.

17 thoughts on “Important Tips for Designing a Hydroponic Production Facility

  1. Some of what I see in your picture is outdated.

    The all-glass greenhouse is a thermodynamic disaster because of heating and cooling costs.

    The lights are too far away from the plants to benefit from the inverse square law.

    1. Hi Steve,

      Thanks for your comment and for reading! We love it when our readers interact. The photo is of a great facility at True Harvest Farms. Are you a grower as well? Hope you have a great day! Stay safe!

  2. I definitely would you would like to contact one of you because that is my plan to do here in North Idaho I start up a couple of greenhouses to grow greens for the county of kootenai Idaho I need to put a business plan together and don’t even know where to start.

    1. Entendemos que o custo das lâmpadas é alto.
      Mas, usar as lâmpadas adequadas economizará muito dinheiro ao longo do tempo.

  3. Hi, I’m Elavazhagan (Ela) from India,Bangalore. I’m going to start two hydroponic farms. One 5000sq ft climate controlled polyhouse for lettuce using NFT system.I’m expecting to produce atleast 20000 heads of it. Another one is 10000sq ft naturally ventilated polyhouse using 1 mtr. Length cocopith grow bags. I have researched a bit and attended a couple of course s. I jus want your opinion on tank capacity for both projects. I welcome any suggestions for any aspect on both projects. Thanks.

    1. This is a great question.
      Our recommendation for tank sizing is simple, 2.5 times the estimated needs of the system.
      This keeps the grower from having to fill the tanks to 100% capacity.
      While also allowing the grower to add fresh water when the EC’s or pH’s climb to high.

  4. Steve ,
    I’ve always wonder about how well informed a grower is when it comes to the application of light in green houses that position light sources meters away from the plant growing area.

    1. In regards to Steve’s concerns: First, the greenhouse in the photo is not a glass greenhouse. This greenhouse uses a twin-wall polycarbonate designed for commercial greenhouse production.
      Second, in commercial greenhouse production the location of the LED grow lights are modeled out before install. Location of the grow lights is not a one variable calculation. The models used accurately predict the light intensities (which are determined based on historical DLI data and shade created by the structure). The location of the lights are also based on light uniformity, creation (or lack) of shade, access to power, labor management, service and crop production systems.

  5. I want to introduce on micro level aquaponic farming in Pakistan to small holding farmers with less capital.
    How we can achieve a revolution level capacity in the growth of foliage and fish with less capital input and higher profits.

  6. Hello Chris, grateful for your comments on use of a non-recirculating system such as the RDI system to reduce buffering? Or even just comments generally? See responsivedrip.com – seems they have had some good successes.

  7. How do u.get the taste is in the cure or what sometime i can that smell and taste, but please i told a friend its all in the seed genetic.please help

  8. Chris, I completely disagree about your buffer for greenhouse structure. Firstly, how high are you referring the structures to be?
    The greenhouse height should not be higher than needed ( based on plants you’re growing) since hot air which is lighter rises and cold, humid air will try to stay lower to the ground. This de-stratification effect can be used to your advantage by venting the hot air out of the roof. The higher the structure is, you will have to spend more energy on conditioning the air.

    1. Swapnil,

      We appreciate your constructive criticism and opinion on this topic.
      My opinion is based on reviews of Wageningen University (NL) research and modeling for greenhouses located in different environments around the world. I also reviewed work done by North American greenhouse manufacturers and as well as agriculture engineers at leading US universities.

      Depending on the greenhouse design, my comments assume a greenhouse gutter height of 5-7 meters.

      By increasing greenhouse height, one increases the air volume that one is managing. The greater the air volume, the slower changes in temperature occur. Moderating temperature fluctuations allows for a healthier environment for crops.

      Thanks for your reply.

      Chris

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.