Hooked on aquaponics

Brattleboro couple spreads the word about a more sustainable way of raising plants and fish
By Alexandra Ossola/The Commons
BRATTLEBORO—For visitors to the home of Mark and Susie Crowther, the blue plastic barrels can be the elephant in the room.
What are those barrels doing in a room of their own, people wonder, and why do they keep emitting sounds of rushing water?
They’re aquaponics systems — closed, symbiotic systems in which the Crowthers can efficiently raise plants for their consumption and fish, using recycled materials and water.
Aquaponics is gaining traction on a larger scale as an alternative to traditional methods of produce and fish farming. In developing countries with a limited water supply, people like aquaponics guru Travis Hughey are introducing the concept as a way for individuals to grow their own food while making the most of their limited resources.
Thanks to some research, seeds, water, fish, and a bit of creativity, Mark Crowther has become an avid aquaponics hobbyist, and he is working with the Bonnyvale Environmental Education Center (BEEC) in West Brattleboro to host two workshops in May.
Aquaponics has been used for centuries, as far back as the Aztec empire, when engineers from Tenochtitlan created floating islands of reeds on which they planted seeds for fruits and vegetables.
These days, though, the systems can be as large as lakes or portable and small enough to fit on a tabletop indoors.
To Crowther, the key to creating these systems is to tailor them to the space available; each one of his systems is built from several 55-gallon blue plastic barrels, one sitting cylindrically on the floor as a tank for the fish, the other half-barrel placed perpendicular on top of the other, as a larger plant bed.
There’s a large hole in the bottom barrel above the waterline so that he can access the fish (in Crowther’s system these are golden shiner minnows, “because they were available at the local bait shop,” he said).
The top half-barrel is full of expanded shale, which is Crowther’s “grow bed media” into which the seeds were planted.
This grow bed media is essential in any aquaponic system because it houses those bacteria that enable the plants to absorb the nitrogen. He chose the shale because it’s lightweight, porous, and local.
“But the grow bed media can even be free,” Crowther said. “You can just go down to a brook or river and pull out a bunch of pebbles.”
The final key component to this system is a small electric pump that brings the water from the fish’s bottom barrel to water the plants on the top barrel. A simple bell siphon then flushes the water back down to the fish tank once it fills to a certain level.
The nitrogen cycleThe concept behind aquaponics is based in the nitrogen cycle, which many of us learned in middle-school science class.
Nitrogen in the soil that was deposited by precipitation takes the form of nitrates, which plants need to grow. (Fertilizers incorporate nitrates for this reason.) All fish excrete ammonia, a nitrogen compound, which can kill them if it accumulates to too high a concentration in the water.
Plants are able to absorb that ammonia in the water with the help of the bacteria nitrosomona and nitrobacter. Because the water is recycled, a closed aquaponics system uses approximately 90 percent less water than traditional farming methods, and the system allows both the fish and the plants to exchange nitrogen to their mutual benefit.
Crowther’s interest in aquaponics came about as a synthesis of many other lifelong interests, primarily with aquariums, gardening, and science.
“[I saw aquaponics as] a way of getting back into traditional gardening and incorporating my passion for being an aquarium hobbyist in the past,” he said.
“We love to farm, but the drawback of traditional farming in Vermont is that once you harvest your food, you don’t get to start up until the following spring,” he added.
“With aquaponics you can grow a wide variety of crops year round,” Crowther said. “I thought maybe it would be interesting to get the fish into the system and farm in a way where I didn’t have to pull a weed.”
Crowther primarily grows cool-season vegetables — lettuce and a few spice plants (including mustard and cilantro) — in his system.
While his system is too small to raise fish that could be “table-ready” (that is, suitable for human consumption), larger systems could incorporate harvestable fish (trout, tilapia, perch, etc.).
Crowther preferred his first system to incorporate local species, which meant that they had to be cold-water fish.

With issues of overfishing from the world’s oceans and the myriad problems associated with fish farming (including larger environmental impact and escapement), aquaponics can seem like a panacea for those who raise fish.

However, the question rapidly arises if the artificial lights, pumps, and materials used in an aquaponics system are more cost effective than the fish and produce grown by more conventional methods used to raise the food that now appears in grocery stores.

Crowther believes that the best way to make these systems economically viable is to suit the systems to their climate; he intends to move his systems outside during the summer, replacing the artificial (and costly) heat and lighting with sunlight.

Tilapia has become popular with fish farmers because they “grow so quickly and reproduce like crazy,” Crowther said, but this type of warm-water fish would require too much heat to be viable here in Vermont.

Cold-water fish like perch and rainbow trout are better suited to the climate, and they still grow large and fast enough to be sold commercially.

To Crowther, aquaponics is ripe for taking hold in the region because “we are already invested in education, sustainability, and organic food and are confined to a short outdoor growing season.”

“Unfortunately, aquaponics has never gained ground on a commercial level in our area because of the brief exposure Brattleboro had to Carbon Harvest,” he said, referring to the currently stalled aquaponics endeavor on Brattleboro’s Old Ferry Road.

Carbon Harvest planned to grow tilapia and various types of produce, but has not gotten off the ground due to financial difficulties.

One of Carbon Harvest’s planning errors, Crowther said, might have been attempting to grow a warm-water fish, which meant that the entire building had to be heated to a tropical level that is simply cost-prohibitive.

“That was too bad for Brattleboro, but smaller systems could work for the community from more of a grassroots level, if not on a commercial level,” he said. “The idea is still worth spreading so people can see the value in farming this way.”

Crowther sees those who would be most interested in aquaponics as people who are interested in sustainable agriculture, who are curious about where their food comes from, who respect nature, and who want to bring some of it into their homes.

With some plans pulled from the Internet, some creativity and a do-it-yourself attitude, anyone can construct an aquaponics system.

“One advantage of this is that it’s not an elitist undertaking,” he said. “You don’t need much money to get started.”

Crowther is working with BEEC and Transition Putney to host workshops at the Putney Public Library on Wednesday, May 15, at 7 p.m., and Sunday, May 19, at 1 p.m., on aquaponics. Participants will learn how to construct their own portable aquaponics systems, and all ages are welcome.

“Once kids figure out that you can very easily adapt an aquarium to grow lettuce with a simple 10-gallon tank and a 5-gallon bucket, they’ll realize that it’s fun to watch things grow and will be interactive with this whole process,” he said.




全日照  8個小時日照 瓜類、茄果類、豆類、山藥、豆薯(地瓜)。番茄、黃瓜、茄子、辣椒等喜溫中、強光性









菜豆生育過程中,主要吸收鉀和氮較多,還要吸收一定量的磷和鈣,才能良好發育。結莢期吸收磷鉀量較大。磷鉀肥對菜豆植株的生長發育、根瘤菌的發育、花芽分化、開花結莢和種子的發育等均有影響。缺乏磷肥,菜豆嫩莢和種子的品質和產量就會降低。缺鈣,幼葉葉片捲曲,葉緣失綠和生長點死亡。缺硼,則根係不發達,影響根瘤菌固氮,使花和豆莢發育不良。 耐陰半陰(大概3-4小時日照) 應選擇耐陰的蔬菜種植,如萵…


◎飼養與管理的重點 只要不是劇烈的變化,錦鯉很容易適應各水溫水質等環境的變化。並不是沒有大庭園就無法飼養,有人甚至在二樓陽台或頂樓陽台造水池飼養。然而我們是欣賞錦鯉雄壯豪邁之氣,因此水池盡量寬闊為宜,以水深1.2m以上為理想。魚池必須有底水排出,過濾循環等設備。用水不一定要取地下水,自來水也可以飼養。
良好的魚餌不會崩壞鯉的體型。餌的量也是在夏天水溫 高的時候,訂定停餌期間,才是整體來說使鯉變胖最重要的秘訣。如果還是想 要給很多餌的話,要增加循還量。錦鯉在水溫超過28度的時候,應給與相當於 鯉全體重量3%的餌。水溫25度時1.5%,水溫20度時0.3%,16度以下則要停止鯉餌,這就是鯉魚長得強壯的要訣。連續不斷地給鯉餌的話,引起內臟障礙, 而影響到鯉不會長壯,甚至導至體型的變歪。


英文版, English version
中文版, Chinese version
西班牙文版, Espanol version 

連通管基本原理 1.連通管原理指的是,在一般開放的空間中,幾個液體容器的底部都相通的裝置,而若任一容器內注入液體,則當液體靜止時,各容器的液面必在同一水平面。

2.兩 端的大氣壓力一樣,但管內兩端的水受重力作用而各自下墜,下墜瞬間,在圓弧頂部拉出一個真空,因真空而有壓力差,此時兩端的大氣壓 力再次從兩端將兩管的水壓回,但壓回的力量是大氣壓力減去管內的水壓(F=(Patm-PH2O)*A),而長管內的水比短管內的水還要重,所以壓回的力 量是短管的壓力大於長管的壓力,所 以,虹吸管內的水就會不斷的由短管端流入而由長管端流出。


4.如果用兩根連通管,但是其中一個連接抽水馬達,此時一根連通管是抽水,所以另一根把水送回,大氣壓力將兩管的水平衡,所 以,一個馬達可以有兩倍的動力,水就會不斷的循環。


簡易潮汐開關 (外部連通管) 1.由於水持續進入水箱,水在水箱和潮汐開關內以同樣的速度上升。(潮汐開關內的底部是連通的)。虹吸管是通到外部的。水會持續上升到外部的開口端。 2.一旦水上升到內部的開口端,它變成一個密封空間。由於水繼續上升,在水箱內水位繼續上升,但速度變慢。同時,水箱內水壓漸大。
(同時會將管道上端部份空氣帶出,因為空氣在管內流動,也是噪音最大的時候) 4.由於水在水箱到達高水位線後,體積空氣被迫壓縮管道,並透過虹吸作用,排出的空氣壓力後,進而開始大量排水。

1.由於水持續進入水箱,水在水箱和潮汐開關內以同樣的速度上升。(潮汐開關內的底部是連通的)。虹吸管是通到外部的。水會持續上升到內部的開口端。 2.一旦水位上升到內部的開口端,直接…