Water Temps for Veggies?

[Two Jay]

Does anyone know the ideal water temps in an AP system for raising the following?

Lettuces, Spinach, Peppers, Tomatoes, Cucumbers, Herbs etc?

[TCLynx]

In Aquaponics everything is a balance, keep this in mind always, we are trying to create a whole eco-system and if you get too into tweaking the system to be perfect for one part, it will probably be to the detriment of some other part. And remember the bacteria as well as fish and plants. This comment isn't just about temperature, it has to do with many other parameters as well.

Also, please don't get too caught up in absolutes. Reading some books, they will insist that some specific temperature is needed. Well if those books were right, then none of my systems should work at all. Like if I needed exactly 74 degrees F to grow lettuce, then I don't know what I've grown in the past but whatever it was seemed to do fine in cool and warmer water.

If you are working in a climate controlled greenhouse and also have the ability to control water temperature as well, you will still have to choose a temperature that will probably be a compromise since different crops like different temperatures (unless you are growing a single crop) but then there will likely be a compromise between the fish and the plants. Again it will depend on fish type and climate. Warm water fish will usually grow best with water temps between 80 and 86 F while most cool weather plants would like the water between 70 and 80 F and even most warm weather plants would probably like the water cooler than the fish would. However if you are growing trout, the situation may be reversed.

To find out the ideal nutrient temps for specific plants, you can probably do some searches into Hydroponics since they have already done the research. But again, keep in mind that these recommendations might not fully apply to your situation.

I can attest that the "necessary" temperatures that people have published in books are not necessarily mandatory!!!!!
I've got a system currently running with 98 F water since the temps around here have been getting up over 100 F for weeks. I will admit that there isn't a whole lot growing well in that system yet (it is a new system) but I have peppers, beans, bananas, rosemary, papaya, basil, nasturtium, and even some sad cucumbers still clinging to life in that system.
In the winter my water temps will probably get quite low since my systems are outdoors, if we have another winter like last, the 300 gallon system will probably have water that is 32 F for a week or so and the lettuce will still survive though it could get some frost burn. I can get away with this since I run locally adapted Channel Catfish though I would recommend against putting very small fingerlings into an unheated system right at the start of the coldest season since tiny fish don't have the energy reserves to go without eating for weeks on end and they starve to death.

Anyway, to find out the "ideal" temps for specific veggies I recommend doing some searching for hydroponic recommendations. But personally, unless you are going into commercial production, I wouldn't worry too much about specific ideal conditions since the stuff you listed won't share much in common, it will be more productive to create a balanced system that will support the veggies, fish and bio-filter and by being balanced it will likely grow all the things you list productively without requiring heating and chilling and climate control.

[Sylvia Bernstein]

As per usual I agree completely with TCLynx, but I would like to add (or rather emphasize because I think she already made this point in a different way) that the temperature of the water really needs to be fish-driven...then fit the plants to the fish environment. If the fish aren't within a temperature range that is comfortable to them they won't thrive, they won't eat, and their metabolism will slow down...and the plants will suffer in turn. If you can handle it, the optimal way to go is to have a couple types of fish that want different water temperatures. Last fall I set up a 200 gallon trout tank in my greenhouse, along with 2 tilapia tanks. I grew spring, or "cool weather" crops with the trout tank (lettuces and sugar snap peas), and summer crops (tomatoes, cukes, broccoli, etc.) with the other two tanks. I ended up giving all the trout away to a friend within a few months, however, because it was such a pain to keep their water cool (50 - 55 degrees) in a heated greenhouse. And I wasn't willing to take down the temperature of the greenhouse because my first goal was heirloom tomatoes in January!

I started and ran the grow labs for AeroGrow International for a number of years, and we did all kinds of experimenting with variables like water temperature. One of the personal lessons I walked away with was that while you can drive yourself crazy doing all kinds of research around optimizing your plant growth, any water where fish are going to thrive (and at AeroGrow we focused on temps where humans are comfortable) will give you 90% of the results an optimized water bath will give you. And not fretting over it is priceless...;-) Hope this helps!

[TCLynx]

Well put Sylvia

Sylvia Bernstein said:

One of the personal lessons I walked away with was that while you can drive yourself crazy doing all kinds of research around optimizing your plant growth, any water where fish are going to thrive (and at AeroGrow we focused on temps where humans are comfortable) will give you 90% of the results an optimized water bath will give you. And not fretting over it is priceless...;-)

[Two Jay]

Well let's start with the fish. I would love to keep trout but I think it will be difficult to both heat and cool the system throughout the year so I am going with heat. Originally we were thinking tilapia, which are still in the picture, but I am seriously considering bait fish since Michigan is one of the nations largest sports fishery. Suckers, chubs, shiners etc. can take the fluctuation in degrees, light, oxygen etc. and they will all accept pelleted food as well. Also, they are all easily attainable in local rivers and streams, which I used to do, and I won't have to clean them. Another benefit, I can sell them at virtually any size for the fishing industry, which means I may have to go with a way to sort them. On a side note, I am contemplating pelleting my own fish (and other animal) food. I don't care for the idea of not knowing what is being fed to my animals on the farm, fish are no exception, since we are eating from the same food chain.

Regarding veggies, I am with you Sylvia, I want heirloom tomatoes and cucumbers (my favorite) year round. The real goal though is diversity throughout the year.

Currently I am working on a chart that shows water temps for various fish species compared to various vegetable varieties. After the temperature comparison, I may work up a PH chart as well.

TCLynx said:

Well put Sylvia

Sylvia Bernstein said:

One of the personal lessons I walked away with was that while you can drive yourself crazy doing all kinds of research around optimizing your plant growth, any water where fish are going to thrive (and at AeroGrow we focused on temps where humans are comfortable) will give you 90% of the results an optimized water bath will give you. And not fretting over it is priceless...;-)

[TCLynx]

There are also some good food fish that will grow with fluctuating temperatures. Like Blue Gill and Catfish that would be locally available.

[Two Jay]

Both have come to mind. Do you think it would be ok for wild caught fish in the system or am I looking for trouble in trying to get them trained on feed, disease etc?

Side note, my grandfather did a study with the DNR about 30 years ago, live catfish in his ponds. They studied the age of wild caught Mudcat / Channel cats. If I can get his pics and scan them in I will share with everyone.

TCLynx said:

There are also some good food fish that will grow with fluctuating temperatures. Like Blue Gill and Catfish that would be locally available.

[TCLynx]

I don't know if wild caught cats or blue gill would be difficult to pellet train, I've not heard much about it. I've heard that some perch and bass might be more difficult to pellet train as would many other types of slower growing game fish. Cats and blue gill are pretty opportunistic so I would expect them to recognize food fairly quickly but I've no experience with wild caught fish.

Most fisheries that sell to stock farm ponds will carry fish that you can use so it might not be worth the trouble to get them from the wild. I get my catfish for 35-65 cents each depending on size.

[Two Jay]

Just checked, I can get locally raised channel cats (4" - 6") for .65 or (6" - 8") for .95 while I can buy Hybrid Gills for (2" - 4") for .65 or (4" - 6") for 1.05. If anyone is interested in comparing prices, I am in Michigan, Trout run (4" - 6") for 1.10 and (8" - 10") 2.20. There are trout in the freezer.... but they won't do me much good now.

TCLynx said:

I don't know if wild caught cats or blue gill would be difficult to pellet train, I've not heard much about it. I've heard that some perch and bass might be more difficult to pellet train as would many other types of slower growing game fish. Cats and blue gill are pretty opportunistic so I would expect them to recognize food fairly quickly but I've no experience with wild caught fish.

Most fisheries that sell to stock farm ponds will carry fish that you can use so it might not be worth the trouble to get them from the wild. I get my catfish for 35-65 cents each depending on size.

[Allisyn Wood]

Hi,

 

I was thinking about the pH needs, too.  Did you ever develop a chart of fish & veggie ideal pH levels to match each fish tank to specific grow beds for those with multiple gardens?

 

Two Jay said:

Well let's start with the fish. I would love to keep trout but I think it will be difficult to both heat and cool the system throughout the year so I am going with heat. Originally we were thinking tilapia, which are still in the picture, but I am seriously considering bait fish since Michigan is one of the nations largest sports fishery. Suckers, chubs, shiners etc. can take the fluctuation in degrees, light, oxygen etc. and they will all accept pelleted food as well. Also, they are all easily attainable in local rivers and streams, which I used to do, and I won't have to clean them. Another benefit, I can sell them at virtually any size for the fishing industry, which means I may have to go with a way to sort them. On a side note, I am contemplating pelleting my own fish (and other animal) food. I don't care for the idea of not knowing what is being fed to my animals on the farm, fish are no exception, since we are eating from the same food chain.

Regarding veggies, I am with you Sylvia, I want heirloom tomatoes and cucumbers (my favorite) year round. The real goal though is diversity throughout the year.

Currently I am working on a chart that shows water temps for various fish species compared to various vegetable varieties. After the temperature comparison, I may work up a PH chart as well.

TCLynx said:

Well put Sylvia

Sylvia Bernstein said:

One of the personal lessons I walked away with was that while you can drive yourself crazy doing all kinds of research around optimizing your plant growth, any water where fish are going to thrive (and at AeroGrow we focused on temps where humans are comfortable) will give you 90% of the results an optimized water bath will give you. And not fretting over it is priceless...;-)

[Teresa N Florida]

Hi Two Jay,

Yes, I too, am interested in knowing if you ever developed the chart of fish & veggie ideal pH levels?

[Miguel Afonso]

The best information on this topic I have found relate to ambient temperatures for growing in soil. So here is the info. The first set of info is the temperature range they will grow and the second is optimal growing temps.

 

40-75 (60-65) Beet, Broad Bean, Broccoli, Brussels sprouts, Cabbage, Chard, Collard, horseradish, Kale, Kohlrabi, parsnip, radish,rutabaga, sorrel, spinach, turnip

 

45-75 (60-65) artichoke, carrot. cauliflower,celeriac, celery, chineses cabbagae, endive, fennel, lettuce, mustard, parsely pea, potato

 

45-85 (55-75) chicory,chive, garlic, leek, onion, salsify, shallot

 

50-80 (60- 70) bean, lima bean

50-95 (60 -75) corn, cow pea, New Zealand spinach

50 -90 (65-75) pumpkin, squash

60-90 (65-75) cucumber, muskmelon

 

65-85 (70-75) Sweet peppers, tomato

65-95 (70-85) egg plant, hot peppers, okra, sweet potato, watermelon

 

info. from

how to grow more vegetables by John Jeavons

[Two Jay]

How to grow more vegetables has been on my shelf for awhile now... borrowed from the library, there is an updated vs. coming out very soon.   It's a good resource.