Backyard Aquaponics
A place to discuss aquaponics

I'm in a jam here folks, growth in this system seems to be stalled, its about 1000gallons, cycled, with plenty of nitrates reading on the tests. PH is around 7.2 give or take. The gravel looks wet because it was sprinkling out when I took the photos. Its a FD system with bells. 3600gph pump with diversion for excess flow. any thoughts on what the prob is here folks?

A few more pics of some problem plants. Now these are all the same plants I grew last year with no problems. The mint and green onions, garlic and shallots are all doing fun. Everything else seems stalled.

Looks like you have a few deficiencies there. Pale/yellowing new leaves is likely to be an iron deficiency and dying tips and edges can indicate potassium deficiency. You can add iron chelates and a liquid seaweed (eg. Maxicrop - regular, not the 'powerfeed' which contains extra nitrogen) containing potassium and trace elements. Mr Damage has some good advice on nutrients. I generally add a scoop of iron chelates and a capful of liquid seaweed to my 1000 litre system when I see these deficiencies - it was an issue when my system had just cycled, but now does not seem to be a problem. A good quality fish food usually provides enough once your system matures.

Someone provided this link a few days ago which might help with identifying deficiencies http://trueaquaponics.com/deficiency-guides.html - their photos and descriptions are useful, but I would search this forum for treatments as there are often readily available, inexpensive products you can get from garden and hardware stores.

What have the temps been like there? Any frosts?

I see you're putting your trip to Minnesota to good use Colum, must have some memories of those cold nights

I found ways to keep warm :p

The tomatoes are looking like mine at the moment, and usually happens when it gets cold. Plus others look like a bit of frost bitten.

I've dosed with seasol and maxicrop. As well as the proper Iron. Temps have been 55-70f. With a random night or two in the last month down into the mid 40s

I'd say it was the temperature then. A bit cold for the tomatoes/peppers.

It should sort itself out as it warms up there. Keep an eye on the new growth from the plants, and if it continues to damage the new growth, it might be something else.

That's what I was hoping. However my wife's got several of the exact same in wicking beds 3 feet away and doing fine.system just not mature enough yet? Too much sun maybe? They get about 8 hours full sun.

Looking at the pics I would suggest you have a Calcium deficiency for sure, as well as Potassium, and possibly Magnesium.

It could be that the root zone of the plants in the wicking bed is staying warmer than the water in the AP system. A root zone temp below 20C will start to cause issues with the uptake of those three elements in plants such as Tomatoes, Capsicum, Chillies etc. At 16C it will be almost non-existent... Looking at your quoted temps, I would say this is most likely your issue, but...

It could also be that there is a general lack of these elements in your AP system due to overplanting of fruiting plants.

Excess Nitrates can cause a lock-out of these elements. When you say: "With plenty of nitrates reading on the tests"... what is the Nitrate level?

Also, are you currently adding any Calcium or Potassium based products, such as Calcium hydroxide or Potassium bicarbonate etc, to the system?... Too much of either can lock-out the other, and Magnesium also.

I think this is probably the case since I find that the wicking beds warm faster than the media beds here in Oregon each spring.



+1

Apologies for the long response time, work has been crazy lately.
Alright, so it's warmed up significantly, and everything except the mint is still stalled out.
Water parameters are,
PH 7.6-7.9,
0 Ammonia
0 Nitrites,
Nitrates 90.

I've been using Maxicrop liquid seaweed with iron, 0-0-1
Potassium Sulfate, K2SO4
DTPA Chelated Iron 10%
Potassium Bicarbonate
Azomite 0-0-.2

Now I haven't added any of the above in about a month to try and let everything stabilize, but I used some of them sparingly in the beginning,
Fish are doing well and water parameters are stable, checked every other day,
I use quality fish feed, water temp is stable at 71-74f.
The growbeds get roughly 10-11 hours of full sun.
Yet everything is stalled, the only thing growing is the mint and strawberries.
I have thai basil in there that lookes to not have grown even the tiniest bit since planting months ago.
Dill that is stringy and keeps trying to bolt. and peppers that are stunted, with tight clusters of buds forming near the main stem, but otherwise no growth.
This is the total opposite of my success with a much smaller system last year. Any insight would be unspeakably appreciated.

Looks like Potassium to me too. Bit of Magnesium too?

Will a potassium deficiency completely stall growth like this though?

I think Chris is going by your earlier pics, do you have any more recent ones? I noticed the pepper had buds in the earlier pics as well. I don't know if your season is long enough to pinch them off but this does seem to encourage peppers to put on more vegetative growth and I think you wind up with more peppers in the long run.

Could be a few things going on. The plants may be stunted because they were put in and stayed too long at temps that were not high enough. It could be a phosphorus deficiency (although I doubt this). It could be a combination of other nutrient deficiencies.

The quick and dirty way to check for the nutrient deficiency is to add Blood and Bone meal - 50 gm/1000 L of grow bed and distributed evenly across the media in the grow beds(reduce this amount if you're running a high fish load). This might be all it takes to get things going. If nothing happens after a week or two when you do this, then I'd consider replacing some of the warm weather plants with those from a nursery (if they are still available and it's not too late for this with your growing season).

Cheers