Backyard Aquaponics
A place to discuss aquaponics

Hey all,

I am almost done my first aquaponic system. I need to decide what to do with my second grow bed. I am thinking of placing some foam over top and drilling some holes for nested pots- that way I can grow leafy greans via DWC in one bin, and other vine based veggies in the other bin.

To build this I used:
- 50 gallon stock tank
- 2 x 30 gallon grow beds (cement mixing trays)
- red lava rock
- 180GPH pump
- 12 feeder gold fish

I have dumped some duckweed from a local pond into the stock tank to keep the fish fed, the only problem is it is clogging my pump every two days. I need to solve this ASAP.

Also, I need some advice from the community, as my photos will show, my swiss chard and lettuce seedlings have barely grown in two weeks. Most of them are falling over but have bright green leaves on them- following other people's aquaponic systems, mine seems terribly slow. Any advice?

Any recommendations or help to get these plants growing stronger and faster would be greatly appreciated!

PHOTOALBUM LINK: http://imgur.com/a/c7iTC/

Welcome bvlaar,

I havnt used duckweed before so Im not much help there. Have you removed the sponge filter from your pump? Its not required and really only causes problems.

Your plants dont look too bad. Use some maxicrop or seasol to assist your plants till the system establishes.

Hi bvlaar, thays a tidy looking system you made there mate, great work.

Your right those seedlings look terrible
Have you tested your system's PH.
what was your water sorce.
have you added anything else to the system.

I think the grow media you have used to strike the seeds is the problem. I used a similar 'glass wool' seedling material. The problem I think is that although the system floods and drains, the glass wool retains the moisture. I have checked mine at all times in the floor anddrain cycles and it is always completely drenched. I am going to change over to a mixture of vermiculite and perlite. After the seedlings have gotten to the size I want, I will wash a the media off and put them in the grow bed.

I don't think there is a sponge filter in the pump > its pretty small. Whenever I open it up I only see an impeller- no filter. I'll take a look at those, thanks!



Thank you! It was fun to build. I haven't tested any of my system's levels yet- I set a budget for the system and have reached it, I may pick up a testing kit if this continues in the next week or so. My water source was a hose from my backyard. The water sat for about a week before I added any rock, plants or fish. Nothing else has been added other than duckweed, but that was recently and even prior to adding the duckweed I was experiencing problems. I'm pretty frustrated about this issue- hopefully I can solve the issue soon!



Hmm, this is interesting. I went outside last night and looked at my oasis cubes, they are drenched even with the system turned off. Over watering could be the issue then. I'm going to remove the plants from the oasis cubes this afternoon and see what happens. It will be tough to get the plants to stay upward with such a small root system in a lava rock bed.

I appreciate all the help everyone. I'll post back in several days after I try and fix this issue.

Have a great weekend,

I have another update, the plants have grown a tad bit in on top, but stems are continuing to weaken. Almost all have fallen over. The tomato plant which has no oasis cube in its roots has continued to turn to a yellow colour. I am thinking it is over watering still?

When my grow bed fills, it comes pretty much to the surface. I've come to understand this shouldn't happen? I'm thinking this may be this issue?

I'm going to buy some hyderton this weekend and make a layer above my lava rock (my media is too big to hold roots just on their own).

My question now is, once I have my layer of hyderton, and a 1 inch buffer of media above the max height of the water when the grow bed is filled, how do I transplant my plants? I will get a few seedlings in oasis cubes, then remove the seedling from the cubes, then what? Should i plant them deep enough that the roots get exposure to water? Or just above the water line?

Any more ideas as to why this is happening would be greatly appreciated!

Thanks!

Here are some pics of the current situation:

I don't have a lot of experience here, but I use crushed lava. I can't tell if mine is smaller than yours, but I planted mine directly in the gravel bed so your little cubes may be holding too much moisture. Maybe try taking a couple and rinsing everything off the roots and planting them directly to see if there is a difference? You should shoot for having the water only come up an inch or two below the surface. Your plants may not like their crowns wet, but if the water is oxygenated enough, they shouldn't mind the moisture in the roots too much. Especially the lettuces since many people grow them in rafts directly in the water. I think you may not get much flow through those cubes, though, so not as much oxygen for the roots.

It may also be a nutrient issue with it being a new system, but I'm not sure. It will also be helpful to see what your test kit says when you get it. My water is too alkaline and some of the plants want it more acidic and are struggling with it a bit. It came down a little just because of the biofilter starting to function, but that could be an issue, too. We also have hard water and that blocks nutrients from plants which I know is an issue.

I planted most of my seed directly in the lava rock. My first few batches were in seed tapes (cut strips of paper and a line of glue. Space the seeds and then add the other strip of paper and plant it) because I didn't trust the seed to not just sink to the bottom. I just sprinkled lettuce seed over one bed and seem to be getting a pretty good germination rate from them so we'll see. My system hasn't been going long enough to harvest anything but the herbs I planted as plants so I won't know if anything I do works for awhile yet!

your water level during your flood cycle is to high.. either lower it or add media.. you don't want the surface of your gb to be "wet" - notice you already have algae (which will be consuming nutrients you want for your plants) in your gb
you want at least an inch of media above your flood level, i like a little more, closer to 2"

Check pH
Take the water level down
Use Maxicrop plus iron or Seasol - this can be added to the water or used as a spray. If your pH is high it will work better as a spray. Before spraying I would remove the lower leaves on the tomato that show any symptoms other than yellowing and wash your hands after this (Looks like the toms possibly have some blight). You should remove these even if you don't spray.

Thanks for the help so far everyone.

I received my pH testing kit today. The results are hard to read, but I figure my pH is sitting too high (between 8.0-8.5). I'm going to read up on how to lower my pH this afternoon. If anyone has some tips to share, I'd appreciate that as well. (see image below)

I went to my local hydroponics store today and they are closed all weekend so I'll need to wait before I pickup my hydroton to make my top layer of media 1 inch above the water line.

Thanks,

Hey All,

Today I purchased some pH down and hydroton. The pH down brought my pH between 7-7.5 it seems which I am happy with.

The Hydroton added about a 1" layer on top of my lava rock. When the grow bed fills with water, the top remains dry. I will post pictures tomorrow evening.

Hopefully these two things will help my plants get back to health!

Update: Pics below

I've seen very little progress with the addition of the hydroton and lower pH. One thing I am noticing however is that my tomatoes and green beans seem to be flowering ahead of the ones in the soil. My little tomatoes in my plant in my growbed are much larger than the ones in my garden- however the rest of the plant looks awful. My swiss chard and lettuce seedlings still have yet to grow.

I was wondering if anyone has any other suggestions?

Thanks all,

Patience! That's a huge pH change so give them a bit more time to adjust. You can give them a foliar spray of maxicrop or seasol and that might help them along as well. The high pH likely caused some problems acquiring nutrients so it might help accelerate the process.

I've found direct seed sowing into the media works best. The seeds planted this way look healthier and grow faster than my shop bought seedlings.

This is probably true most of the time except when water temps are low. I've had pretty good luck with transplants as well but I've never tried using the rockwool blocks.