TL;DR: We are winding down the barrel-ponics proof-of-concept experiment. We achieved 50% of the harvest yield that we had hoped for, in the bountiful periods. But there are a lot of improvements we’ll implement in our second prototype, which will help us come closer to our target.
Below is a graph of yield per week over roughly the last six months. We averaged 50% of what we calculated to be the ideal yield per unit area during the better periods, and about 35% overall.
Although we did not reach our goal, there were tons of improvements we could have done to increase the yield. First of all, we did not harvest any fish during this time period. We also made the typical rookie mistakes of not waiting for the initial cycle to end, and not measuring the ammonia/nitrite/nitrate levels in the beginning to see what was going on, as mentioned in an earlier blog post. Also, most of the time, we had a lot of empty patches where we could have planted other vegetables. So, in short, our first prototype was nowhere near optimal, and thus we did not see optimal yields.
Another discovery that we made during this time is that our assumption of the amount of food needed to make up 90% of an adult’s diet were way off. Our assumptions might hold for vegetarians or vegans who eat a lot of plant-based foods, but even our family, which probably eats more fruits, vegetables, beans and nuts than the average family in the US, would get all the food we needed from just 50 to 100 square feet (the area we thought 1 to 2 adults would need for 90% of their diet).
Our next steps are to make the next prototype, with the focus on making the system more convenient to change when you want to try something else, or fix when things go wrong. Incidentally, this prototype will be our first AutoNanoFarm prototype. We have some exciting ideas we’re trying out right now and designing into the product, so stay tuned!