Backyard Aquaponics
A place to discuss aquaponics

I thought this might be a handy thread to start. I know many people struggle with high pH systems having trouble growing certain types of plants.

My system is a pretty solid 7.6 pH most of the year and some plants suffer from Iron deficiency pretty badly but others are doing great even without excessive Iron additions.

Peppers (capsicums) seem to do quite well in my system.
Rosemarry
Meyer Lemon cuttings
Bananas
Lettuce
Purslane
Basil
Bamboo
collard greens
mint
carrots
turnips
radish
Parsley
dill
fennel
cilantro
swiss chard
sweet potato
marigolds
onions
leaks
oregano (though it will occasionally show signs of iron deficiency but still does well)
aloe (provided it gets a little shade)
napa cabbage
jicama

and I'm sure I'm forgetting more that have done well for me, those of you with high pH systems, please share what does well for you anyway.

Here are a few plants I've had little if any luck with in AP
Cucumber (needs lots of iron during certain periods of it's growth and rarely has done well for me in AP)
Okra (I've managed to grow it in AP but it suffers greatly from Iron deficiency)
Nasturtium (leaves turn almost white from Iron deficiency)
squash, zucchini, pumpkins, and gourds (I guess too similar to cucumbers for my ap system)

Strange that you get those results... these are mine:

Plants that DID NOT do well....
Oakleaf, ok that might've been my fault but I found out that they were one of those "bitter" lettuces.
cauliflour - they didn't seed well so I think I'll either grow them as seedlings elsewhere or buy seedlings.

Plants that did well for me:
Basil
Marigolds - definitely! good companion plant for anything
Cherry/roma tomatoes,
Capsicum (red varieties) - because AP is watering them all the time I had to give them more sun. under normal/traditional methods, I have them growing well in dappled shade/5 hours sun with moderate watering. But in AP, water comes through every hour of the day so I have to put them in more sun 8+ sun to ensure success.
Lebanese cucumber omg these love AP... you gotta try it!! again lots of sun recommended
Celery I ended up with way more than I need.. they became monsters last year.

I'll be doing some of these again this year... some with more seedlings and others fewer due to needs. Will also try some carrot, cos lettuce, rosemary, thyme and peas this year...ohh and brussels sprouts!

looking forward to everyone's posts!

great post - thanks TC.

Since iron deficiency is the biggest problem. How do you solve it? I have heard of iron chelate - where would you get normally (fish store, plant store, feed store) - is there a chemical/brand name for it?

I am just guessing that it might be hard to find here in the desert so...Do you think you could you just buy a bunch of iron and let it rust in the system? I know I can get re-bar here easily - probably just find some laying around somewhere (this is the construction capital of the planet).

Of course, I am not sure re-bar is only iron so that is a problem if it has other metals.

will look for the chelates first

best way... pump more, plant more, feed more... simple

the chelated Iron is sometimes kinda hard to find and can be a bit costly but the important thing about it is the way it makes the iron more available to the plants even at the higher pH. Some people have put iron into their grow beds but I don't know if there is any scientific evidence that it actually helps. The iron content of your source water is likely to have a bigger impact on the usable iron in your system. My source water is fairly low in Iron and I have issues while I know some other people running systems at the same pH as mine and they don't have any trouble with iron.

Well, if it is hard to find in Florida then there is no way I will get it here -

My pH is around 7.4 and I can grow more cucumbers than I can eat, but I do add 1 teaspoon of chealated iron per 1000L each month.

I have also had good success with beetroot, silverbeet/rainbow chard, radish, rockmelon and brassicas seem to love it too.

Strangely I struggle with tomatoes compared to the dirt garden.

Too many variables just to blame pH on poor plant growth.

too true there Simo



Just because it is hard to find here doesn't mean a whole lot, my part of Florida has generally acidic soil so there is little need for most people to use chelated iron. Apparently it is quite easy to find for the Aussies and here in the US it is probably far more common in places with limestone soil (like South Florida or out west.)


Also take heart, I'm finding that over time, some things that didn't do as well in my first season, are worth trying again. An aquaponics system improves with age.