Symbi Biological

Volunteer Integrated Pest Management—Ladybug Larva

We’ve got some aphid eating volunteers visiting the aquaponics greenhouse for the third year in a row. This video is of a lady bug larva on one of the lettuce leaves. They like to eat aphids and other soft bodied sap sucking insects you may find in your greenhouse. You’ve probably seen ladybugs for sale at your local nursery as part of an Integrated Pest Management program. If you’re lucky enough, they might show up for free depending on where you live! Our region near the California coast seems to be a particularly attractive place for them. The University of California Agricultural and Natural Resources says the adults typically over winter somewhere cold like in the Sierra Nevada Mountains. The cool temps lower their body temperature slowing their metabolism so they can live off their body fat until it warms up. In Spring, they head west to the coastal and valley areas of California to find food and eventually lay eggs. It’s always interesting when they find the greenhouse. There is rarely a shortage of aphids inside! I wish they would stay for longer, but they usually leave after a short stay. Lady bugs are great for integrated pest management, but you should always consider that they do look for greener pastures fairly quickly. That’s why I tend not to buy them for IPM since it seems they stick around for only a short snack and then go looking for something else. That said, they’re always welcome to a feast anytime they find us. Bon appetite! Or, should I say, Bon aphidtite!

Aeration and Crud


Aerating your deep water culture beds is a really good idea for more than just the obvious reason of keeping your plant roots healthy—it also helps keep your system water clear. Introducing oxygen to the trough sustains healthy root development in the aqueous conditions with ideal levels being at about 8ppm of DO or dissolved oxygen. The plants will grow at lower levels, but so will other things potentially opening up your system to disease and other issues. Clearly, healthy plants mean a better harvest with fewer pests and a more natural disease resistance. But also, from a food safety perspective, keeping the beds active and moving is a better way to ensure there aren’t pockets of anaerobic sludginess building up in your system. The sludge buildup can cause a host of problems from increasing BOD (biological oxygen demand) of the system to physically covering your roots and essentially suffocating your plants.

We often focus on the fish as the reason for the filtration in the system, but the plants also have a role when it comes to suspended solids production in your deep water culture troughs. That’s why it is vitally important to aerate your system beyond just the fish tanks. As plants grow, they slough off root cells and produce root exudates through photosynthesis feeding bacteria which grow in the system troughs. Without some form of turbulence in the trough, the organic matter will continue to build up away from the primary filtration in your system.

In our experience, airstones placed every 4 feet in the deep water culture troughs helps to ensure there is enough oxygen getting to the plant roots and also provides enough turbulence to suspend the solids, which will eventually be captured by the filtration to keep your water clear. 

Keeping the crud out of your troughs allows you to keep a consistent DO and assists the beneficial biology to stay healthy and do their jobs more effectively providing more nutrients for your plants to grow healthy nutrient dense produce. When designing or redesigning an aquaponics system, make sure you remember to aerate your troughs.

Microbial Ecology of our Aquaponics System

NASA syringe sampling

Angela Detweiler takes sample. Photo by Sander Van den Groenendaal

Learning more about the microbes in our aquaponics system and how we can improve or encourage those actors to do their jobs more efficiently has always been a goal of the Symbi Biological program. Put another way, we’re talking about the microbiome and microbiome eco system services that are performed. We know that there are certain nitrifying bacteria doing most of the heavy lifting in aquaponics, but what others are present and what role to do they play in nutrient cycling? 

We volunteered to provide samples as part of a very exciting NASA study of the microbial ecology of food production systems. Scientists from the Microbial Ecology / Biogeochemistry Research Laboratory at NASA Ames Research Center will determine the


Photo from

microbiome of our aquaponics system Read More

Measure to Manage: Nutrient Analysis #5


Every so often, I post our nutrient analysis of the aquaponics system water using a Hanna photometer. In the last 6 months, things have been fairly consistent except for the winter months. As the system temperature dropped below 57F, the nitrification slowed somewhat and the nitrite level jumped significantly. I think this was a result of both the cold system temperature slowing down the bacteria and a catfish tank that had fewer fish than I thought. Fish food was collecting in the tank and probably contributing to the nitrite issue as a result. I had been concerned that the catfish were not growing and decided to empty the tank to see what was going on in there. As it turns out, the catfish were almost the same size as when we started last year! Read More

Wormery Frogs Evicted


Last year, I started to notice an increase in Pacific Tree Frogs in the Wormery. At first, they were cute, but I did notice that my integrated pest management team of spiders and other critters of the worm bin were slowly disappearing. Back when I started the worm bin, we had a diverse group of insects and invertebrates. So many that it compelled me to make a video called Critters of the Worm Bin where you see all of the major players in a worm bin from a worm’s eye view at 10x and 15x magnification. Filming a pill bug eating a worm is still one of the coolest things I’ve ever seen.



Then about a year ago, it became obvious that making that film again would be next to impossible since most of the critters starring in their roles had disappeared. I don’t think they were on strike. They were gobbled up actually. Slowly, the frogs were beginning to take over the worm bin. Reluctantly, I’ve been gently relocating them outside where they belong. When I first noticed them, I figured they were eating some of the worms as I mentioned in a previous post. Upon further observation, I think they were eating a LOT of the worms! Not exactly surprising, but if you see frogs in your worm bin, I’d suggest showing them the wonderful natural habitat they already have or you’ll be raising frogs like me. And making fish food from frogs, well, I’ll leave that for someone else to try!

Surviving Not Thriving


Consistency is so important when raising any kind of organism for production. I’ve said it before on this blog, but it’s so important to have consistent inputs to expect predictable outputs. This is certainly the case with the crickets this morning. When I entered the cricket castle (okay, it’s a tent), it felt kind of cool inside. The thermometer showed it was 65F in the day time and the nights were getting down to 55F inside the tent… ahem, “castle”. It’s supposed to be about 84-88F, but one of the heaters had shut off on it’s own. As a result, the crickets have been surviving and not thriving. I use this phrase a lot when discussing the health of plants, but it works very well in this instance. Just because something is alive and looks “okay”, it may just be that the organism is close to it’s breaking point and has not presented the symptoms just yet. The little troopers were hanging in there, though. I was especially concerned with the new crop of babies as they are a delicate bunch. Everything seems okay with them, but they’re pretty small so it’s hard to truly know until they get a little bigger to see what the numbers look like. At these temperatures, breeding stops as I learned all too well back in September. The solution to this is to have a monitoring and alarm system that calls you when a set point is not being met. Or, for simplicity, just another reliable heater in the room. Although, if this is your livelihood, I’d highly suggest an alarm.

Symbi Moving Forward


“So what do you feed the fish?”, she asked. I had just finished explaining how aquaponics was the perfect answer to recirculating aquaculture and hydroponics as it is an elegant system that solves the main issues of both production systems. She had a very good point, though. And that night, as I lay awake in bed thinking about that very question, Symbi Biological was born as I began to imagine a biological loop that we could create on the ranch where we work. That loop has been what I’ve been working on the last couple years while also working on projects for the TomKat Ranch Educational Foundation helping with regenerative agriculture strategies.

Over the past few years, Symbi Biological has worked on a number of different subjects to solve problems in a public way so that others could learn from and share these experiences. Some of those projects worked out really well, like the crickets, and others… not so well. However, in either case I believed it was important to document my experiences and share them openly. My ultimate goal with Symbi is to de-risk some of this stuff so others can replicate it with confidence when it counts.

All that said, we are in a pretty critical moment right now when it comes to our climate and it is more important than ever to build our understanding on how we can do a better job of stewarding the planet. Symbi’s parent organization, TomKat Ranch Educational Foundation, has asked that I focus my time over the next couple years on helping them discover and share the agricultural practices that offer the most promise for growing a regenerative food system that feeds us all and sustains our planet. Please visit the website to follow the exciting applied science projects and data that are helping point agriculture in a new and inspiring direction.

This blog will continue to publish mostly about aquaponics and insects as I can fit them back into the schedule. I feel it’s important to share this information with you so that you know why some projects are on hold. It always frustrated me when I would find blogs that I liked and then they would just stop posting with no explanation or even if the project worked or not. Or they would sporadically post. I hope to someday soon continue working on other food issues like the Fish Food Project, but for right now, I have a goal of educating the public about the importance of regenerative agriculture. So if you’re new to what I’m talking about and want to learn more, please join our great team at You can always reach me at Thanks for reading and I look forward to producing more content very soon!