A Community and Forum For Aquaponic Gardeners

Growth so far this spring

Hey everyone, I'm new here. I got my very first aquaponics system up and running last fall. I tinkered with it all winter and got some things growing (albeit very slowly) this spring. Seeds are sprouting, roots are abundant, fish are healthy and growing, but the top growth after sprouting has been slow. Some of the leaves are yellowing too. I wondered if it is just not warm enough yet...what kind of growth have you had so far this year?

I have a 275 gallon IBC with about 25 4-6 inch tilapia in it and 6-10 comet goldfish.

There is a 4'x4' media bed with lava rock and a 4'x8' DWC bed, both of these are about 12 inches deep. The media bed has a bell siphon which cycles about every 17 minutes.

Attached are a few pictures.

Thanks for any suggestions you have.

Rich

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Replies to This Discussion

Permalink Reply by Liz & Dan on March 30, 2016 at 6:27pm

What kind of fish waste is being produced at this point to support the plants? If you just have baby fish, maybe not enough nutrients in the system yet and you might need to supplement with a safe fertilizer?

Permalink Reply by Richard on March 31, 2016 at 11:18am

I have some good sized fish, this may be the case i guess, do you have any recommendation on a safe fertilizer?

Permalink Reply by Liz & Dan on March 31, 2016 at 12:04pm

I think most AP sources will recommend Maxicrop Liquid Seaweed (http://www.theaquaponicsource.com/?post_type=product&s=maxicrop). Typically this is to get a system up and running while their fish are small. The only concern with the Maxicrop is using too much over time that can encourage salt buildup. If you have a system that is maturing with deficiencies, you may also need to supplement some iron and get composting worms in your grow beds. (Hallam mentions this in the following video: https://www.youtube.com/watch?v=dcoc26YbTa8 and you may notice that some of the Maxicrop products have iron added to them). Then another question is have you been using composting worms in your grow beds? They can help make the nutrients more available for your plants and keep the system cleaner. You can add small amounts of organic matter (i.e. banana peels and other clean kitchen scraps) in your grow beds that the worms will eat and add more nutrients than just what your fish food provides.

Finally, are you trying to grow plants completely out of their season for your location? If you are in the Maricopa County area, refer to this publication from the UofA for a reference. Aquaponic systems will still be governed by the time of year (temperature, levels of sunlight available, etc.) http://extension.arizona.edu/sites/extension.arizona.edu/files/pubs...

Honestly your plants look a little nutrient deficient from the pictures. Yellowing in older leaves is often nitrogen deficiency and the tomato looked a little phosphorus deficient, but this could be partially due to the temperature being too cool for those plants (tomato and peppers love heat). As the water temps start to rise I would expect some of that to resolve on it's own, but I would add some amendments to be on the safe side, especially ones I mentioned that wouldn't hurt your fish.

Do any of those suggestions sound like something that might help?

Permalink Reply by Richard on March 31, 2016 at 2:24pm

I have been wondering if I have a nutrient deficiency. I have added worms to the media bed, just recently though. I will get some of the liquid seaweed and try the kitchen scraps as well.

In regards to the plants and season, I referenced that exact article, I have tomatoes, peppers (both were transplanted) and radishes and onion from seed. Maybe I read the calendar wrong. In the rafts I have some lettuce as well.

Thanks for the ideas!

Permalink Reply by Liz & Dan on April 4, 2016 at 9:00am

I'm glad you've got the planting calendar and have been using it! I created a small indoor AP system to grow lettuce in the summer and it still bolted in air conditioning. I think the daylight length has something to do with it... moral of the story is to stick to the planting calendar :) Our spring was really so warm that I would expect your heat loving plants to be doing better...

Let us know if the worms start to help with the mineralization of your nutrients. I would expect they will do wonders for your plant roots. And adding a little extra nutrients from the seaweed should also help. I didn't ask before, but what are your numbers? pH, nitrates/ites, etc... Our water is typically a very high pH and that can screw up nutrient uptake as well.