General items for supplement fertilizer?

[arthoz]

I'm looking replacement for three kind of fertilizers: iron, calcium and potassium.

Iron I heard we get it in form of iron chelate found in pharmacy. Could I replace by using iron nails?

Calcium well I'm not sure how...is blackboard chalk ok as replacement?

Potassium, well I heard it's plenty in wood ash...

Is there other ways like rock dust or something similar?

Any ideas? It's hard to acquire chemical stuff in my hometown...

[Outbackozzie]

Dont worry about getting seperate elements.

Get hold of a product called Maxicrop : http://www.maxicrop.com/pages/product_1.html

Just make sure to get the 100% organic concentrated stuff, and dose to the tank at about 1 cup per 1000 litres.

[arthoz]

Thanks for the advice but I kind of defeat my real purpose. The people I'm working with have this principle of creating our own material for use. In rural areas especially in East Malaysia(Borneo), there's no source of factory made products or it is too expensive to get. I'm trying to create something which could be done in-situ.

I've read that fish manure lack three main substance which is calcium, potassium and iron? Is this true? I did see some sign of yellowing of my plants leaves or maybe I was just paranoid...

For example the source of potassium or potash in the past was acquired by leeching it from burned wood or leaves ash. I could get a sizable and endless supply of potash from our orchard refuse (yes, open burning. I know it's not environmental friendly...any ideas for a better and cheaper source of potash?).

Now I need to know how to acquire sources of calcium and potassium. I got some blackboard chalk but not sure if it's a source of calcium or if it's safe to use--are there other substance I could use?

As for iron, I'm totally at loss here. Apart from iron chelate I'm not sure of any other way to obtain sources of iron.

I heard that laterite soil are red because the high content of iron and aluminium. Is this true? Any geologist here who could help me out? If it's true is it possible using laterite stones (batu kawi) as a source of iron? Or could I just put iron nails inside the growbed?

This is not an issue of being a cheapskate or overly thrifty. It is the matter of self reliant. If I could create a workable and practical way to do it, it meant a lot to people who want to practice aquaponics in remote region of the world.

Please help, we would be forever grateful...

[Ravnis]

An old farmers remedy was to put rustable metal in a bucket of water and let it sit till the water turned red from the rust then pour this on plants in the soil for Iron deficit. If you tried this you would want to be careful you did not get galvanized nails as the zinc and copper that would enter your water as well is harmful to the fish.


Chalk is calcium carbonate or calcium sulphate depending on the source. The plants and bacteria will chelate this mineral so it can be absorbed. That conversion will be the bottleneck for you as they can only do so much at a time. I currently use pickling lime added to white distilled vinegar to increase my calcium content because the maxicrop is $23 a gallon and the pickling lime is $3 plus $2 dollars worth of vinegar. Look up adding calcium to reef aquariums and you will find more ideas.

If sea shells are a possibility for you then that might be another option. Are eggshells available to you too? These will buffer your ph as well as add calcium. Have a good read of the forum threads and you will find these problems addressed in a lot of threads and see some real creative ways to handle them in a sustainable fashion.

As far as the pottasium in ashes, there was an old method of making soap in which the ashes were boiled and the potassium hydroxide and potassium salts were separated due to the different densities at the temperature of boiling water. If you search on the web, I think you may come across some written guides for this.

[arthoz]

Thank you Ravnis...that was insightful...

An old farmers remedy was to put rustable metal in a bucket of water and let it sit till the water turned red from the rust then pour this on plants in the soil for Iron deficit. If you tried this you would want to be careful you did not get galvanized nails as the zinc and copper that would enter your water as well is harmful to the fish.

But I've read somewhere that the iron would rust and turn into something else that can be absorbed by plants unless the water is acidic...could someone confirm this? Is there a way to be sure of the iron level? The only people I know with a lab to test it is about 8-10 hours ride away from my home.

I might not see them in two months time so I can't really check if this method is reliable (but it is interesting and I will try it---after I learn to know what type of nails that are not galvanized)

As for laterite which basically can be found all over Malaysia. English surgeon Francis Buchanan travelled along the western coast of southern India and published his manifold observations and results...he wrote (1807): “What I have called indurated clay …is one of the most valuable materials for building. It is diffused in immense masses, without any appearance of stratification and is placed over the granite that forms the basis of Malayala. It is full of cavities and pores, and contains a very large quantity of iron in the form of yellow and red ochres. In the mass, while excluded from the air, it is so soft, that any iron instrument readily cuts it, and is dug up in square masses with a pick-axe, and immediately cut into the shape wanted with a trowel, or large knife. It very soon after becomes as hard as brick, and resists the air and water much better than any brick..."

Is it possible that I leech iron from laterite like putting it in a bucket of water?

[nwestwood]

I'm also looking for another way to add Iron. If I don't add a teaspoon of chelated iron every 2 weeks, I get yellowing lettuce leaves on some plants. The problem is that the Iron turns the water dark red and I can't hardly see the fish, it takes 10-14 days for the water to clear, and then I have to dose it again. There has to be a way to do this so the water stays clear.

[David McPherson]

For the past 12 mths I have been using a 220 ltr barrel partially filled with oyster shell lids as an aditional filter on my system Since I started using it I have had stable Ph @ 6.9/7 and was wondering why as everybody said that Aquaponic systems PH drift down Yesterday I decided to clean filter which I have not done for some time as I flush it every day When I opened filter I realised that leval of shells had dropped checked original photo and found leval 75/80 mm lower Approx 14 lts volumn of shells (calcium) had gone into system I am now thinking of adding iron maybe filings nait etc to filter to see if iron deficency can be overcome easily and cheeply David

[Outbackozzie]

Use the chelated iron as a foliar spray to avoid staining the water.

[Murray]

That is interesting David and I am sure you are right.
I should make one or two up for my systems.

I have to buffer mi systems weekly to keep the pH up to around 6.8 - 7 and if I forget for a few weeks it quickly gets down to 6

Can't see a reason why the nails idea would not work.

[nwestwood]

Outback - when you make up your spray, how much do you mix? Do you spray lettuce as well as other veggies? Does it stain the lettuce leaves?

I like the idea, just need some details on the implimentation.