Maybe I shouldn't have asked for a rule of thumb. How about this question. Would a 5000 gallon fish tank and 720 square feet of grow beds allow for producing enough food to feed two adults year round if properly maintained and going full time?
IMO that would basically cover most of your veggie and fish needs provided you have a staggered growth plan. This will not provide for your grain squash/ melon or other large area plants in a survival or independent living environment.
The way I produced my own calculations was to reverse engineer what I and my family ate previously. So how much of each veggie did your family eat last year? How many lbs of spinach? How often did you eat corn? How much flour did you use to make bread? After you have these quantities, you can look at the methods used, like square foot gardening, consecutive planting etc. Don't forget to grow enough for winter consumption.
I am very interested in your concept/ project and would like to help you so you don't waste time and money and turn this fantasy into your dream. Please feel free to contact me with any questions.
The estimates I'm getting from people are all over the map. Some have told me four people can be fed with a 500 gallon tank. Most have said 5000 gallons and 720 square feet of grow bed would feed a village. I'm really surprised this hasn't been nailed down yet, since it seems the key point of selling aquaponics. If you have X and Y you can grow Z food to feed your family...
Thanks for the info. Sounds like you're talking more about the variety of food that can be grown, rather than the quantity of it, if I'm understanding you correctly.
We are talking basic math here. At a max of .5 pounds of fish per gallon you can put 250 fish in a 500 gallon tank-if you know what your doing. It takes 7-10 months to grow your fish to eating size. Maybe you could harvest a fish a day - not much to feed 4 people. Conventional yields of hydroponic crops are established and Aquaponics does not offer statistically significantly better yields for more than a year, aside for the fish crop. Even then, the yields depend on many environmental factors. I think what Carey is saying is that it is hard to know if you can provide for a family or a village if you are not specifying how and what they eat. If you provide that you can research hydroponic yields that will give you the answers you are looking for.
Remember that when you are talking about "key point of selling" that the people selling you on aquaponics are the people selling aquaponics for a profit and they generally look at the data in the most positive light. I think most people who have spent anytime working on systems, developing science behind those systems and thinking about aquaponics will tell you aquaponics is not a panacea. It is a part of a broader set of solutions that will reduce consumption of water & energy in the production of food.
I'm not even going to talk about lighting (I believe using sun is far more efficient), I'll let others do that.
When most people say a _____ size system will feed a family, they are generally talking about salads and tomatoes. NOT the family's entire diet. If you are talking about trying to grow enough veggies to feed a couple people 100% of their calories and food, it's a very different situation. It takes a lot of space/time to grow grain.
And as noted, how are you going to feed the fish? Do you have to some how provide the food for the fish from the system? And what about replacing the fish or will you start out with some breeders and try to keep the stock going? What about seeds and pollination, will you be trying to breed the plants and save the seeds for future planting? That takes some extra space too since you have to leave a little of everything to mature and produce seeds.
I did read once about a guy that survived on only the produce of his 4000 sf organic garden. I understand he grew and ate a lot of potatoes and was very very skinny.
It is a more complex question than you realize.
To one person who is used to eating out most of the time, a 5 gallon goldfish tank and a storage tub to act as filter and grow some lettuce is probably "enough" in their mind because they just enjoy an occasional salad or lettuce to put on a sandwich and they are not thinking about all the other "food products" they buy.
Thanks TC. Good info. Maybe aquaponics isn't the silver bullet I had hoped. I figured vegetables and fish would be enough to cover the vast majority of our diet. I don't know much about grain or if that is required for diet.
Feeding the fish...I was planning on feeding them slugs and duckweed. Slugs are plentiful where I'm at, and I'm under the impression that duckweed isn't hard to grow. As for breeding, I would have a 500 gallon tank for that. As for seeds, I haven't scratched the surface on breeding plants and/or storing seeds.
I appreciate the info.
As to lighting, it's my understanding that there are LED lights that can change colors to simulate the seasons and get vegetables to grow faster than the sun. I haven't used any though, so I don't know.
@ Jonathan: Cheers mate. You do understand. Thanks for helping me out.
@ TC: good points. Thats kind of what I was getting at. Thanks.
@ Rick: I have been attempting to be off-grid since the mid seventies and have only recently been closer to success. There is so much to learn, then have to apply it into practice. Yes I was talking about variety but also quantity. I don't know where I got it from but the following chart is what I use to guide my planting plans in my personal garden. I believe AP is the core of better, more sustainable farming/ gardening but is not a one size fits all, cookie cutterable, silver bullet.
Really, if you want to be food independent, you need to consider what you eat and how often. You also need to figure what your raw/ initial input is, so you can properly feed your food for a healthy diet.
You asked how much grow space is needed. Well there are several methods used. ie row gardening vs square-foot gardening. Row gardening is the simplest and most common method of growing and produces decent results but if you want really intensive usage then Sq Ft gardening wins hands down. For example with one square foot of grow space one can grow a pepper or broccoli or cabbage. Put ten of them together and you have a ten foot row garden. With SqFt Grdn; one can harvest about three to four times the quantity compared to row garden. If properly managed, one can grow 16 radishes, four heads of lettuce and one head of broccoli in one planting, in the same Sq Ft. Add on successive planting and you can get (based on that one Sq ft); broccoli in spring, summer tomato and fall leeks. Now if you stagger this planting method and plant a new Sq ft every ten days throughout the appropriate growing season, you can get a nice salad throughout the year, stir-fry for dinner along with some meat. I hope I'm not confusing you.
Anyway, the following is what I use to plan my garden:
*This is just a guide and does not represent a balanced diet. Feel free to adjust this chart to suit your personal needs.
This gardening cheat sheet for you that lists how many of each vegetable you should plant per person. For example, broccoli is 1 per person so if you have a family of four you will most likely need to plant 4 broccoli plants. These numbers are just averages so you might want to plant more if you are planning on canning tomatoes, making pickles from cucumbers, making basil pesto or you just really love a certain vegetable!
* These numbers do not take into account succession plantings, so if you want enough carrots to feed your family throughout the year you should plant the indicated number whenever you do a planting.
Thank you very much for the info.
Rick all of those numbers are low at best. aquaponics is great 'till the power goes out. I wouldn't count on it for a survival situation.
5000 gallons of aquaculture/ponics maybe. but with no power you'll have a hard time keeping it going for 6+mo. the amount of fish feed is going to be outstanding. if you are planning on being outdoors, figure on 2 acre p/person min. I'd raise chickens, goats,sheep , milk cow, and definately pigs. potatoes, ftw!
This thread is very interesting. Is aquaponics hype?
Aquaponics is great but there is also a lot of hype out there too. Where aquaponics wins is it is the most water wise method since it is recirculating and you don't loose water down into the ground unless you have leaks. So it is a method of aquaculture that removes the need to waste water by doing water changes. It is a means of hydroponics that eliminates the need to dump and replace the nutrient every few weeks. This of course means it is all a bit more complex but you get to grow more food for every drop of water. Now there are of course drawbacks like needing more electricity and initial capital outlay compared to dirt gardening but you don't get fish from your dirt garden either and I'll admit it, I'm lazy and I like the automatically watered/automatically fertilized nature of aquaponics.
Aquaponics is only hype if you are listening to the aquashyster e-books that tell you that you can grow 10 times the veggies in half the space in half the time.
And the LED technology is coming along but I don't believe they have gotten it to the point where you can use LED's for 100% of the lighting and still get good growth.
If designed correctly, one can do AP without electricity by using water towers and hand/wind pumps esp in combination with greenwater aquaculture.
IMO AP is the basis of a well rounded, sustainable organic garden/ farm. Soil is the other half of of this biomitigation process.
Beware! There is A LOT of hype out there but the basis and theory of AP is sound for healthy food production.