Iron deficiency is a big topic in AP. Well, i just found a good example of a typical Iron deficiency and i thought i will share it.
As most of you know: Plants need Macronutrients and Micronutrients (Essential nutrients), to complete its life cycle. Every element has its own function, and it cannot be replaced by another element.
Macronutrients are called Macronutrients because the plant needs it in big amount (>500mg/kg dry weight) and Micronutrients in smaller amount (<100mg/kg dry weight).
Some deficiencies show the same symptoms, in many cases chlorosis (yellow leaves), so sometimes its difficult to say which element causes the deficiency.
#There are only N,P,K, (Mg) which are Mobile nutrients - the symptoms occur on older leaves first.
#Immobile nutrients (such as Iron), if there is a lack of one of these, the symptoms are shown on younger leaves first.
Lack of Nitrogen or iron, both show yellow leaves. So, if you look at the picture, you can see, the older leaves are dark green, so it cant be Nitrogen, as it is mobile and occur in the older leaves first.
As the young leaves are completely yellow, you know it is iron deficiency.
So, by looking at younger and older leaves you know if its a mobile or immobile element which causes the deficiency.
If anyone is interested in more pictures of deficiencies, i can post them time by time. (sorry for disturbing the people who already knew it)
Ebay is your friend... you can get just about any chemical that is legal shipped to you.
Something like "HESI" P-K 13/14 (it's a hydro product that usually is used as a flower booster might do the trick...
In the past I remember this HAKAPHOS product being GREAT for seedlings (foliar) as well as flowering (fertigation). It's water soluable granular mineral fertilizer N-P-K 13-40-13 plus trace elements. This (HAKAPHOS) is the one I'd recommend, only because I've used it much in the past and was really, really satisfied (plus it's cheap). You need an EC meter though (for such small seedlings something in the neighborhood of 600-800 micro-siemens twice a day foliar should do...If you do end up getting this and don't have an EC meter I can give you a rough "teaspoons to gallons" measurement. (Or if you have a quality gram/milligram scale I could work out the weight per gallon measurement of 800EC for you in a second...
I'm in another part of the world so that fertilizer might be called COMPO instead of HAKAPHOS (call and ask) where you are at...?
Here is their USA contact info:
(Really any hydro P-K product should do though...so if it's a no go just do what Johnathan suggested)
|COMPO North America, Inc.
P.O. Box 5106
Vero Beach, FL 32961-5106
|Phone: +1 772-285-1363
Hi Allisyn. I'll get those measurements for you by the end of the day (when I mix up by batch for the pepper seedlings). I wouldn't really add anything like the above products to an AP system for a number of reasons. The COMPO (or any similar product might be particularly bad if added to the system water...but even P-K products would probably cause more headache than good...unless you could do it like this... http://aquaponicscommunity.com/group/fish-less-systems/forum/topics...
or some variation thereof for those heavy feeding plants...of course you can always foliar feed (even when plants are big). Foliar comes with it's own drawbacks though (like inviting disease anytime you wet the leaves). Now, when foliar feeding things like potassium, copper, manganese (the last two not being a smart thing to do near an AP system) or anything that will raise the pH on the surface of the leaf your probably OK as far as fungal diseases go...
Time and a good quality fish feed and a smart buffering regime (like rotating potassium bicarb one time, then dolomitic (for the Mg) lime the next, then hydrated/builders lime) might be all you need once your system 'matures' a bit.
I for one am not really that patient, so like the 'dual root zone' set-up because it allows you to cater to that (each) particular plants needs independently of the others and without affecting your system water (causing huge algae blooms, killing your fish etc...)...without having to wait for the system to 'mature'...or having to settle for a "middle of the road" approach (different plants, in different stages of development all receiving the same 'nutrient solution')...
Ok, Allisyn...I decided to feed some flowering plants in the yard and get those numbers to you. Curiosity got the best of me...
Hekaphos/Compo 13-40-13 in a level teaspoon (it weighed out to 3.10 grams) put into 1 US Gallon gave me an almost spot-on EC reading of 600
But again, it's not something you should just dump into my fish tank...
Jon Parr is currently using the dual root zone method and says he's really happy with it. You can go "all natural" with it like he's doing (I think he adds worm poo, rabbit poo, saw dust, compost, and granite dust into the top mix, while the bottom roots hang out below the flood line of his media bed in AP water...even that 'natural' stuff would be bad to dump directly into your AP system of coarse...
it's cool because you can do one container organic, one mineral salts and compare...or try out different organic mixes etc...and see what you find works best for you, all the while not contaminating your AP water with excess nutrients...)