I have been experimenting with an outdoor hydroponics system using different types of stonewool and it hasn’t been a raving success. I now understand that I need a drip or flow system rather than manually watering once a day, and bugs decimated my pea crop before I understood the problem. I’ve been looking into aquaponics systems, which seem to be expensive when compared with hydroponic systems. How much longer does it take to break even with aquaponics versus a hydroponic system and what is the difference in start-up costs? It will still be outdoors as I am several years away from setting up any kind of a greenhouse. I live in New Mexico.

You should take comfort in the fact that there are literally tens of thousands of people scratching their heads over these exact problems right now. If you’re very quiet, you can even hear the scratching. You’re correct—aquaponics does have a higher start-up cost than hydroponics. Building your own system using a manual such as the IBC of Aquaponics or the Zero to Hero System will minimize your costs and save your sanity, but there’s no way to get there without spending at least a few hundred dollars. Purchasing a pre-fab system is likely to cost thousands of dollars.

Then you get into challenging questions such as whether to shut down in the winter, move indoors or build a greenhouse. An article on my website, frostyfish.com, titled “Aquaponic Economics” can help you think about those choices. I grow year-round here in Wisconsin, so I know that year-round growing can be done cost-effectively. Assuming a reasonable food cost (half of farmers’ market prices), a system built according to one of the plans mentioned above can achieve a payback of two years, not including your labor. This estimate, however, assumes you won’t kill any fish (which you will). How close you come to a two-year payback depends on how careful you are, and how much you learn beforehand about how to operate it.

There’s a hot debate about whether you can grow faster in aquaponics or hydroponics. University researchers in Australia and Canada have both shown aquaponics achieving faster growth in side-by-side tests with much larger root systems, but hydroponic system designers raise legitimate concerns about the test methods. At the end of the day, it’s reasonable to suggest that they’ll achieve similar growth rates.

Comparing the cost per gram of nutrients, hydroponic powders are cheaper than fish food. However, aquaponics makes a lot of sense if you want to raise your own fish to eat. For me, a fresh trout dinner is the best part of my garden. It’s also fun when the neighborhood kids stop by to feed my fish and test the water.

As for your pea plants, I don’t know what kind of bugs ate them, but I can tell you that most aquaponic gardeners manage pests with beneficial insects like green lacewings and ladybugs. My green lacewings are beautiful and have a great sense of humor. I read Douglas Adams aloud to them, and they would laugh if their mouths weren’t so busy chomping aphids.