Backyard Aquaponics
A place to discuss aquaponics

I could do with a bit of advice on some of my plants. I seem to have it that plants either thrive, or die, with very little inbetween.

In the thriving department has been: Cos, Silverbeet, Celery, Snow Peas, Broccoli, Baby Spinach


In the dying department are: Beans, Cucumbers, Zucchini, Rocket, Capsicum

In between are my Cherry Tomatoes, which haven't grown taller, but thicker, have lots of flowers, but only 1 tomato.

Can anyone give some advice about what it might be about my system that makes it so?




Currently pH is 6.4 (was running at 7.2 until recently). other levels 0.0 (except ammo at 0.25).

Temp is jumping around like a Victorian spring (12-18 deg)

Salt is 2ppt.

I only have 3 fish (trout) in at the moment, after loosing a few during the cycling process.

I add a tbs of Iron Chelate every 2-3 weeks.

Too much iron maybe

got any pics?

how many litre system, by the looks of your build thread its an IBC?

thats a LOT of iron.

In my ibc ive added possibly 1 heaped tbs in a year. My tomatoes are going nuts and prior to that snow peas and chinese greens.

Nitrates at 0.0 indicates your fish arent producing enough waste.

If the nitrates were 0 but the nitrites and ammonia were high id say it wasnt finish cycling, but that isnt the case.


Just as an experiment you could try a foliar feed (spray the bottom of the leaves) with seasol or powerfeed (fertiliser version) diluted in water as per instructions see if that helps.

Tomatoes aren't being pollinated? Try flicking the flowers.
My bell peppers seem to grow best at a steady, cool temp. They took forever to actually produce.
Why is the salt up to 2ppm? If the fish aren't sick I wouldn't be adding salt.

fish were sick. Its in his build thread, they have a rotting disease like i got on my trout

Beans aren't keen on salt and the water/root zones temps are too cold for Zuchini, Capsicum, Tomatoes.

One levelled teaspoon of Chelated Iron per 1000L every six weeks is more than sufficient, too much can be an issue. Also, once your pH is below 7.5 it's not required.

With your pH at 6.4 you'll be wanting to buffer the pH up occasionally to stop it dropping below 6.0... use either Calcium Hydroxide or Potassium bicarbonate. These will buffer your pH up and will also add Potassium and Calcium, essential for fruiting plants. I prefer to add the Pot' bicarb every 3rd or 4th time and the Hydrated lime on the other occasions, there is a balance that needs to be observed between these two elements and I've found if I added them alternately then the Calcium ended up locked out after a few months... I've just experimented with this again in the last couple of months to reconfirm it in my own mind.

Thanks Yabbies, great summary.

How often would you apply the potassium bicarbonate and the hydrated lime (in the 3:1 ratio), and how much of each would you add?

Also, I can see hydrated lime at the the big B, but I am not sure where to get pot' bcicarb. Any suggestions?

Potassium BiCarbonate.. sold as Ecofungicide... (and hydrated lime).. are available from Bunnings...

Thanks Rup, helpful. Any suggestions on quantity?

Only apply them as required, ie: as your pH drops into the low 6's... Bring your pH up by no more than 0.3 in any one 24hr period, my IBC system holds 500L and I've found when my pH is down around 6.0 about a 1/4 of a teaspoon of either will bring the pH up by about 0.3

The Pot' bicarb can be bought from Bunnings as "Eco-Fungcide", supposedly it contains surfactants, not that anybody has reported an issue with, but if your worried about such things you could google "Pure Potassium bicarbonate" and see what you can find around your area.

Cheers!

Edit: did see the duplicated info when I hit submit... just couldn't be fagged changing my post!

Thanks Rup and Yabbies, you guys are gold!

agreed with the above,

I find a teaspoon or so of hydrated/brickies lime at a time is enough. then wait a day or two then take another ph measurement then go again.


Its cheap at liek 8 dollars for a 10-20kg bag....too bad we only use a teaspoon of it.

you can buy 5kg bags of hydrated lime at Masters (for about the same price as the 20kg bag!!)

Any one got any thoughts about what is going on here?