Agriculture in the marine/oceanside environment

(Larry G) #1

I would like to avoid negative discussions. It is well-understood that micro-nations, city states, and isolated populations are rarely entirely self-sufficient and simultaneously prosperous. The great advances of human kind have taken place from trade and interaction, specialization, etc.

However, to be completely reliant upon others is foolish and risky. Some level of self-reliance and productivity is necessary for risk management of supply chain interruptions, and a completely sterile environment devoid of plant and animal interaction is unhealthy for humans psychologically.

Therefore I would like this thread to concentrate on what is practical, what is already economically proven, and what is theoretically feasible, and be educated and entertained by this specific subject along the way.

Cheap and realistic approach?
Possible uses for seasteads
(Larry G) #2

Here are some resources for education:

The use of saline waters for crop production

Saline Agriculture: Salt-Tolerant Plants for Developing Countries (1990) (Free PDF Downlad available at link)


I have downloaded the links you gave and have one open now for reading in Sumatra. Thanks, please continue.

(Larry G) #4

Sustainable Production, Intensification and Diversification of Agriculture, Forestry and Fisheries in Small Island Developing States

The role of agriculture, forestry and fisheries in the sustainable development of small island developing states

(Jonas Smith) #5

Do you want to discuss technologies such as aeroponics in this thread…technologies that are suitable for an isolated population regardless of their environment? Or do you want to focus specifically on ways to use the marine environment (saline water, etc) in agriculture?


I’d like to see discussion and data on aeroponics, because it reduces weight and the need for processing heavy dirt. At the same time the motion of the floatie vs the flow of water in the aeroponic system is a concern.

(Larry G) #7

I’m good with aeroponics/hydroponics. Just wanted to get the topic defined as being related to growing food plants and animal husbandry for seasteads and marine environments, rather than devolving into some economic or philosophical argument about justifications for doing so. I’m more interested in practical technique and cost than what one person or another sees as their ideal seastead lifestyle.

I personally prefer my systems to be low-touch, and it seems that hydroponics/aeroponics require constant monitoring and fiddling adjustments. But I could be convinced differently.

Low touch could be weekly/monthly monitoring rather than daily, IMO.


I agree. I am thinking there is a hybrid, where real soil buffers and stabilises the aeroponic water chemistry and biota. It’s my understanding (which may be in error) that root crops do not do well with aeroponics. Praps a dirt-farm-floatie with potatoes, carrots, asparagus, etc will provide drainage water to be sprayed on tomatoes, cabbage, strawberries, etc roots, with due diligence to which plants get along with each other, naturally.

The idea of floating acres of veggies certified organic and pest free, is appealing.

And of course the other thread about integrating agriculture and waste management.

(Larry G) #9

Well, that would be expected where the most useful part of the plant evolved to be encased in dirt. Where the most useful part of the plant evolved to be above ground, aeroponics might work better.

But just because the handful of European and North American crops we’re most familiar with have achieved global domination through selective breeding for shelf-life, doesn’t mean they’re the best crops to take with us to the Seastead. The first Europeans on the N American continent nearly starved before they adapted and adopted some native plants. Getting masses f human being to change their eating habits is one of the absolutely hardest things to do. Billions in advertising over literal decades has been used to get us to our current levels of sickness and obesity.

There are thousands of palatable, nutritious, local vegetables, fruits, and nuts that have never been seen in your local supermarket, because they don’t grow local to you and they don’t transport well. this can be said for any “you” out there.There are a GREAT many critters out there that are as tasty as pig, cow, and chicken, some better, many with a lower agricultural footprint.


I think i’ll feed those critters to the perch, catfish, trout, tench, etc freshwater fishes, which will provide nitrogen to the aeroponic system. That’s something the wild salt water fishes cannot help with. Plus, you need a reservoir of irrigation water, so why not grow fish in it, and feed them the grasshoppers (which you could grow intentionally) and dead honey bees (for pollination). Ideally, the seastead will have little to no land-based pests.

One of the urls you gave has interesting data on saline waters, and plant growth. While ocean water is way beyond what is considered “saline freshwater”, i am thinking that only one pass thru a distiller (not two) is good enough, plus untreated rainwater, and minor leaks of salt contamination to the irrigation water are of no concern pertaining to plant growth.

(Larry G) #11

Depends on the species. Some are more tolerant than others, but if you start with heirloom varieties, you can sort through a few generations for salt tolerance, if you’re patient. But in general, plants don’t require nearly as fresh water as people do. People don’t really require as fresh of water as generally thought, at least for periods of time. Many sailors survived drinking 50/50 casked fresh (stale) water and seawater when supplies got low.

Also, distillation should be one pass anyway. If you boil and condense it, it’s not carrying anything with it that isn’t volatile- no salts.


I agree about the quality of the water in general, i am trying to find a cheap, high enough volume filter method that removes oil, algae and their fish-kill poisons, and unlimited amounts of macro items, without the filter being clogged or damaged. A filter that uses only low-grade energy (no high pressure pumps), and can accept it in small or high quantities (90F ok, 300F, ok, on for 5 minutes then off for 6 minutes, ok,…), is a plus too. That leaves distillation, running on roof heat, deep-water cooling, and whatever heat “waste” the human situation gives off, slowly pumped around by free wave/wind energy. My biggest concern was the tolerance for pinhole leaks, and sloshing, and sloppyness during cleaning the equipment. I am no longer as concerned as i was about the salt, and diseases can be controlled with submerged UV lamps, heat, etc.

(Larry G) #13

I’m digging the dewvaporation links you posted. I can see some great applications for that.

Aquaponics — Integration of Hydroponics with Aquaculture (free PDF)


Yeas, it has promise, but also gotchas. The stuff is made of polyethylene, so essentially no glue sticks to it under pressure. The fine print (patented) has mention of external steam supply, and a vaccuum. And it’s real possible to overheat and melt it, so no pouring water onto it from the generator engine’s exhaust manifold heaters. And it’s plastic, so no UV light. On the other paw, it’s ~34 cents per sq ft in diy qtys, which makes it cheaper than roofing tin, and it won’t dissolve in salt water. It’s way less thermally conductive than the tin roofing, but i figure a stack of 10 will move 60,000btu without too much trouble. If it costs $200 but lasts nearly forever, and reduces replacing the paper, carbon, and RO filters to once a year (or longer), processing raw salt water, then it’s a good deal. But i can’t tell on land how it will work on the ocean.

(.) #15

I am convinced. Food production through agriculture is imperative.
, I think ,
Hydroponics an aeroponics are important.

I need some practical experience.


Conclusions i have come to in the last week of reading is: human “waste” can be put to good use growing lawns, ornamentals, trees, and bugs. Bugs are fed to fish, fish “waste” water is used to grow veggies. Anything grown and dead to this point can be composted and used in root crops which would rot if grown in an aero/aquaponics system. Any grasshoppers which jump off the floatie will attract and feed the wild salt water fish.

This puts the desalinated greywater reservoir to double duty, feeds the veggies appropriately, provides freshwater fish and mussels, attracts salt fish, etc etc… There’s still a nitrogen surplus, but perhaps that can be made into ammonia as a stored fuel.

People are making money doing some of this already.

(.) #17

As a general rule of 3s in human survival (desert).
3 min without air, 3 hrs exposed to the elements without shelter, 3days without water,
3 weeks without food.

So in a desert environment, when I see a rabbit, the first thing is not to kill it
and use it as food, but look at where it hides from the heat, where does it find water.

priorities are important. Some people would work up a sunburn and a thirst, and
would still not get hasonpfeffer.

Agriculture is important.

But , may be, floating first

(Larry G) #18

There’s plenty of sub-forum threads for that. Thus the whole point of separating it out and asking for only on-topic commentary in the VERY FIRST POST. Most of the people on this forum will never seastead. Some of them will probably never get on a boat. Some of them will contribute insight on various central or peripheral topics nonetheless. Others don’t contribute much at all.

It seems like every singe thread here gets polluted by negativity and off-topic commentary (& bickering!) of little to no value. This particular thread is about agriculture. Right next to it, literally two clicks away are multiple threads about how to float. I find some of those interesting too, that’s why I comment about agriculture here, and about floating THERE rather than going OVER THERE and telling them that they should look at agriculture first. Wonderful thing, forum threading. It allows people to talk about what they want in nearly simultaneous but separate conversations on the topics they’re actually interested in.

The agriculture I am interested in also happens to have ramifications beyond floating cities, it’s of interest to islanders as well, which has great potential to solve multiple problems in terms of quality of life in some very impoverished areas, on a much closer timescale than mass migration to floating cities.

(Jonas Smith) #19

Guy named Adam Bearup did a project back in 2011 building an entire underground facility for animals and agriculture. It was in Michigan, so not exactly a “marine/oceanside environment”. But since I believe that most agriculture (for consumption) done on a seastead will need to be indoors due to limited exterior space and to avoid the hostile environment I think these domed-earth shelter projects might be interesting to research.

The blog is only up to part 5, but there are videos of the project here and there is also a documentary available from Amazon for $20.


Part 6 is here.