You should contact the state lab and ask them. I'll bet they will do N testing. The above posts are correct about N changing seasonally. Farmers often need to test N levels to gauge fertilizer needs for crops. My Extension lab does it, but I didn't even bother last year when I got a test. I did everything else though, and learned my copius compost additions have raised my P and K to very high levels. Not saying you're in that situation, but in my case, I sure won't add any P or K fertilizer. If I think N is needed, it'll be something like urea or 29-3-3 lawn fert so as not to boost the P and K and farther. This post was edited by toxcrusadr on Thu, Feb 7, 13 at 11:04

I think the comment about a new thread was directed at hottina44 and their question about indoor lighting. That was off topic. alex_g76, Some of those metals are perhaps toxic to mammals when ingested in too high a dose, but that is not the same as with plants. The plants will only take up what they need and leave the rest. Besides, if you look at the actual amounts of metals it is very tiny. Most are MICRO nutrients anyway, and are only needed by plants in very tiny amounts. They might be build up in the potting soil over time, but potted plants should be re-potted with fresh soil every few years anyway, long before the micro-nutrients will build up to any noticeable levels. So you need not worry about that imo. Btw, it's not commonly known, but almost all organic fertilizers are made for and will work best in In-Ground plantings. Organic fertilizers are made of raw ingredients, such as blood meal and bone meal, etc. Those components cannot be used by the plant as food itself. The fertilizer relies on the micro-organisms in the soil to ingest the raw ingredients and convert them to chemicals (yep, chemicals) that the plant can then uptake into it's roots. If those organic fertilizers are used in relatively sterile potting medium, not much happens. They pretty much just sit there. And your plant can starve while there is lots of food sitting right there. The components (nitrogen, potassium, phosphorus [NPK] and other macro and micro- nutrients) that the soil organisms produce from the raw ingredients in the organic fertilizer, is the same at a molecular level as what you find in a standard non-organic fertilizer. The benefits of organic fertilizers in the soil is that they feed and therefore increase the soil micro-organisms, which is great for the soil structure and the roots of the plants. Unfortunately this dynamic is very, very hard to reproduce in potted container plants. Therefore I always recommend standard non-organic fertilizers in container plantings, preferably a liquid type, or a slow-release pelleted type, such as Osmocote. Also, as a side note; the metals and minerals in fertilizers cannot by law be called “organic” because the law states that a component has to have Carbon in it and be derived from a once living source to be labeled “organic” Of course these items do not contain carbon and have never been alive. So if you see a fertilizer labeled “organic and natural”, the word “natural” is in reference to the mineral and metal ingredients only. In reading the posts on the thread that bmelz linked, about fertilizing in containers with organics, it does look like some have done it with success but do note that most of what they are talking about is seasonal vegetables and some short lived ornamental plants. Those are often re-potted annually with fresh mix and compost. That works quite well as there is a lot of micro-organisms in compost and manure. But that type of mix also breaks down very quickly, usually be the end of a growing season. When mix breaks down the speed of water drainage slows down a lot. If you're re-potting every spring that's no big deal and the old soil mix just goes back on the compost pile and new mix is made. But with a long lived plant like a citrus tree that soil break down is problematic. Citrus are very sensitive to soggy soil. Most will say they're sensitive to over-watering, but it's not really the water that's the problem, it's the lack of oxygen in an overly saturated, soggy soil. Plant roots need both water and oxygen, so in a long lived plant like citrus using an open and airy mix that lasts a long time and doesn't break down fast is very important. Unfortunately the components of those kinds of mixes, such as Al's Gritty mix and the 5-1-1 mix are pretty sterile. Hence the recommendations of standard non-organic fertilizers. Now if one was to re-pot their citrus trees annually or semi-annually with a compost based mix, then I do believe an organic fertilizer would work. But for myself, I would find that way too much work.

The concept of a "winterizer" fertilizer is really a misnomer because not very long ago the synthetic fertilizer manufacturers and sellers were advising people that used them to not fertilize later than Labor Day. What feeding the Soil food Web now will do is give the plants a food to store so those plants are ready to grow when spring soil temperatures tell them it is time. About now you should be feeding your lawn with a good source of organic plant food. keeping in mind that soil temperatures lag behind air temperatures by quite a bit and the Soil Food Web will still be busy in a good, healthy lawn long after the air temperatures drop below freezing.

You can check out some "before" pics here :) Please note that the before pics were taken in March, 5 months after overseeding and the grass didn't have the chance to fully grow. The "after" pics that I'm posting right now were taken in September, I believe. I went organic right at the beginning of my journey with lawn care and I've never really used chemical fertilizers. I don't live in the US, actually. I'm Polish and I order my SBM and alfalfa pellets online. $15 for a 30 kg (65 lbs) bag + $5 shipping, next day right at my doorstep :) However, I can't find corn gluten meal anywhere here in Poland! Now, not to hijack my own thread, is there anyone who can help me with my original question?