Aquaponics Application

Ledge Top Farm & Four Seasons Aquaponics

Owner: Tom Mitchell

487 Lyndeborough Center Road
Wilton, NH 03086
Hillsborough County

daytime phone: (603) 620-7302
evening phone: (603) 654-6002
Web site:

Application Date: 2016-02-02

Applicant Details

Please briefly tell us why you are applying to be part of the Certified Naturally Grown program: *
We started an aquaponics greenhouse last year. We follow organic standards and we want customers and the public to know we are adhering to organic standards. CNG is the only means to do that in this state.
Are you currently third party Certified for your produce operation by any other organization (Organic, Biodynamic, etc)? *
Have you ever been certified in the past? *
If yes, please note which agencies and dates: *
1993-2002 NH state organic certification
Have you ever been denied certification? *
How did you hear about Certified Naturally Grown? *
I've been a member for many years.

General Information

Please check all crops you grow in your aquaponic system. *

Please specify what other crops (if any).
Please check all markets you grow for (this will be displayed on your farm profile to help potential buyers find you). *

Please specify what other markets (if any).

System Design and Management

Please indicate what type of system you use (for hybrid systems, check all that apply): *

If you indicated you use an "other" system type, please specify what other type of system you use here.
If you use wicking beds, describe how the water his handled after it is used in the wicking beds. Does this water recirculate? If not, how is it disposed of?
What materials are used for root support, growing media, tubing and pipes, tanks, troughs, and other materials that come into direct contact with system water? (check all that apply) *

Are there any other materials you use in your system that are not listed above? If so, please indicate them here.
Dura Skrim R20WW 20 mil thick liner
If you use soil or compost in your system, where is it used? Is it used only in the dead-end portion, or also in in the recirculating sections of the system?
If you use compressed grow plugs, what is (are) the product/s name/s? Have you been able to confirm with the supplier that it/they do not contain synthetic nutrients?
If your system contains cement, does it come into direct contact with the water? Please describe how cement is a part of your system.
No Cement
If you use wood in your system, is it treated wood? Does it come into direct contact with the water? Please describe how wood is a part of your system.
No wood contact with water, but wood that is close to water is not treated.
If your system includes IBC totes purchased used, have you been able to confirm with your supplier that they were used only for food grade uses? If so, how have you confirmed this? If not, how do you intend to confirm this?
The one IBC tote we use was labeled to be filled with fruit juice, and was confirmed by the seller.
Please note that while IBC totes can be grandfathered in when they're in already in use at the time CNG certification is sought, CNG standards prohibit the introduction of IBC totes once CNG status is obtained. Please indicate that you understand this restriction on IBC totes by checking the box here. *
Does water circulate at a rate sufficient so that the water volume of the fish tanks(s) recirculates each hour? If it recirculates at a lower rate, please explain. *
The volume of the fish tank is 625 gallons. The flow rate circulates at 600 gallons per hour.
Briefly describe how your system achieves appropriate aeration. *
A 1.5 inch PVC air tube delivers air via 1/4 inch air line every 8 feet to the growing beds. There are 4 of these for the fish tank.
Briefly describe how your system achieves appropriate degassing. *
The troughs are open to the air as are the fish tanks for gas exchange.
Does your system include any of the following: roofing materials, recycled plastics, or plastics that contain BPA? *

Water Sources

CNG standards vary according to water source. Please indicate below ALL water sources you use for your aquaponic system, and answer the corresponding questions.
Do you use Municipal water? *
Do you use well water? *
What are the ground water contaminants of concern in your region? *
There is arsenic in some area well waters. The levels are far below the EPA limits in our water.
What experts did you consult to determine contaminants of concern? *
The water testing company called "ChemServe" provided a fact sheet on the contaminants of concern and the levels of the contaminants in the well water.
Have you tested your well within the past year, and if so, what were the results? *
This well water was tested in 2015 and there was no levels of contaminants above EPA standards in the water.
Are you willing to start testing annually? *
Do you treat or filter the water before adding it to the system? If so, what methods are used? *
There is iron in the water so it is filtered with a micro mesh filter before use. This filter traps sediments and adds nothing to the water.
Do you use rainwater? *
Do you use surface water? *
If you use a water source that is not named here, please elaborate.

Water Quality: Nutrients, pH, solids

How do you ensure a good match between stocking density and crop production? *
We use test kits. We also look at the plants for deficiency symptoms. We use a recommended density of fish per area. Currently 3 gallons per fish.
Please describe how you design and operate your system to provide biofiltration that corresponds to production of fish waste and crops. *
The lowest point of the system which is at the fish tank level drains into a pumping barrel. The water is pumped into three elevated settling tanks which are designed so the solids drop to the bottom of these tanks. This is cleaned weekly. The water moves to a 250 gallon IBC tank which serves as a biofilter. Bioballs are used to increase the surface area of the tank. Microbes are cultivated here to breakdown any fish wastes. The water then moves into the troughs where the plant roots remove the nutrients. The water then returns the fish tanks, all by gravity. The biodigestion continues in the troughs.
Do you ever add supplemental nutrients? If so, what materials or products have you used? List ingredients and product names. How much of these do you use? How frequently? *
Chelated iron, Potassium carbonate, Calcium carbonate, epsom salt (Magnesium sulfate) has been added to the system. Kelp and rock phosphate have been added also.
Do you use worms in your system? *
What materials do you use to buffer pH? *
Most buffering came from the maturing of the system, but we have added Potassium carbonate and Calcium carbonate
What methods do you use to prevent the build up of waste solids in your system? *
three settling tanks as described earlier. These are emptied weekly.
Please indicate how often you monitor each of the following:
pH? *
tested each week
Temperature? *
recorded each day
Dissolved oxygen? *
Look at the fish and plants for problems. I have ordered DO test kits (Feb 2016) and will start monitoring this soon.
Ammonia? *
tested monthly
Nitrites? *
tested monthly
Nitrates? *
Tested periodically but looking at the color of the plants is better.
Use this space if you'd like to share additional information about your water quality and monitoring practices.
The plants and fish are growing fast. The plants are healthy and show no deficiency. The fish are hungry and active. The biology of the system gives great information about how things are growing.

Seeds, Transplants, and Crop Health

Do you grow some or all of your own transplants? *
What growing media do you use? Please list the ingredients. *
Coco coir, vermiculite, rockwool
Do you use any chemically-treated or genetically modified seeds? *
Do you purchase some or all of your transplants? *
Describe your primary insect pest challenges AND methods of prevention and control. (Do not answer "none". You MUST indicate actual pest challenges or LIKELY challenges, and you must ALSO indicate how you manage or how you would manage them. If you indicate a product, also specify how often it's used.) *
Aphids are our biggest challenge. We use ladybugs and Azamax(a neem product) to control them. We have also used Encarsia formosa to prevent white fly outbreaks, which have not happened yet.
Describe your primary plant disease challenges AND methods of prevention and control. (Do not answer "none". You MUST indicate actual disease challenges or LIKELY challenges, and you must ALSO indicate how you manage or how you would manage them. If you indicate a product, also specify how often it's used.) *
We have a necrosis of basil leaves, mostly on older plants packed together. Looks like powdery Mildew. Separating plants helped reduce it. Getting rid of non productive old plants helped too. We are cleaning rafts that have mildew on them with Oxidate.
CNG certification requires the use of certified organic or Certified Naturally Grown seeds whenever available. Please indicate the suppliers from which you source - or will source - your seeds if your application is accepted and you continue the certification process. *
We have organic seeds from Johnny's Selected Seed and High Mowing seeds. If I buy local seed it is organic.
Please indicate, by entering your initials, that you understand that CNG strictly prohibits the use of chemically treated or GMO seeds. *
Please indicate, by entering your initials, that you will as a general rule purchase organically grown seeds, AND that you will only purchase conventional seed when the variety you wish to grow is not available in certified organic or CNG form. For each variety purchased in conventional form, you will identify (and keep records of) at least three commercial organic seed suppliers who do not carry that variety. *

Fish Management

We do not offer certification for fish, but do set some limited standards for fish management where they might affect the produce and or quality of life for the fish.
Does hormonal sex reversal treatment ever occur on-line / within the recirculating system? *
Please describe the practices you use to prevent and treat fish disease.
We keep the fish healthy. Feed them with organic food (from Aquaponics source) and give them greens daily. We have seen no disease yet in the past 7 months.
Have you ever found it necessary to use antibiotics? *
Please describe what kind of fish feed you use. Is it organically grown? (For aquaponic produce certification CNG standards do not require that the feed be organically grown, but we are interested to know what producers are using and to give credit to any producers who may be using organic feed) *
Tilapia grown by my partner in his aquaponics tanks. He did not use organic feed, but it has been the only feed we used since being here.
Do you use black soldier fly larvae or duckweed as supplemental feed? *
Do you use any supplemental feed besides BSF larvae or duckweed? If so, describe it here, and indicate how you protect against contamination of your system. *

Protecting Against Contamination

Is your operation partially or entirely INdoors? *
What are the nearby land uses? Are there any that might pose risks of contamination? *
The greenhouse is surrounding by Ledge Top Farm, a CNG farm
How does your ventilation and air filtration system prevent possible contamination? *
All inlet and outlets are covered with screening.
Do you share space (including fish tank, seedling starting, or plant production space) with other producers? *
Is your operation partially or entirely OUTdoors? *

Waste & Energy

These questions will not determine certification status, but are intended to encourage producers to review our recommendations in these areas and to give credit to producers who have made investments in the sustainability of their operation.
How do you dispose of fish solid wastes? *
Solid fish waste composted and are used as side dressing for Ledge Top Farm soil plantings.
When necessary during system change over, how do you dispose of nutrient-rich water? *
It could be used as irrigation water for Ledge Top Farm.
What measures have you taken to conserve energy, improve energy efficiency, and/or use energy from renewable sources? (This could include system design, siting, insulation, crop and fish species selection, and more.)
The end walls of our greenhouse are insulated to R-20 and the edge of the side walls are insulated to R-20. The plastic is doubled to provide insulation R-1.25. All water runs by gravity except for one pump. The greenhouse is south facing with no tree blockage for maximum solar exposure.

Inspections & Networks

A core requirement of CNG certification is the on-site peer-review. Getting this completed is facilitated if you're a part of a network of aquaponics producers who might serve as your inspector. Are you a part of a network (informal or formal) of aquaponic producers in your geographic area? *


I understand that only the produce, NOT the fish, can be labeled and sold as Certified Naturally Grown. *
I will not label, or in any way lead consumers to believe that produce not raised in accord with CNG standards is Certified Naturally Grown. *
I understand that I have to complete at least one Inspection(s) of another CNG aquaponic producer in my area each year, if there is one within a one hour drive. *
I understand that the inspection I conduct will NOT be of the same producer that inspected me. *
I have reviewed the Certified Naturally Grown aquaponic certification standards, I understand them, and I will abide by them. I understand that if I have any questions I may contact CNG for clarification. *
You may use this space to tell us anything else you think we should know about your operation.