I like the crop and forest analogy, but aren't we "cropping" by even growing roses at all in a garden environment? I can see that the adequate N availability would be provided by plants growing, dying and decaying in a meadow or a forest. The trees provide their own N by shedding leaves which decay, which nourish. Ditto grasses in a meadow. But a rose is by definition a crop, isn't it, unless you're talking about a species rose that thrives in a natural environment, like rugosas on a beach or a woodsii at the edge of a forest? A crop being something planted in an artificially provided for growth zone for the planter's own purposes. In that case, I don't see the roses as being able to provide for their own needs, being such heavy feeders. But maybe some teas could or as michaelg says, some shrub roses. By that time, though, their roots are like tree roots and the roses have become a forest?? Have to think about that. Goodness, roses are fun! I think I agree with taoseeker, though, just need to spend time, years no doubt, experimenting with mulches and methods of fertilizing to see what works best. I wish I'd started growing roses when I was 2.

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?

How large is very large? Do you happen to know what kind of lawn it is? In that locale, fescue, rye, Kentucky bluegrass, or some combination of those, would be the three (plus combinations) most common. Off the cuff, any good synthetic fertilizer (Vigoro, Lesco, Scotts' if you must) with a high level of nitrogen and low everything else is going to work fine. So Vigoro 29-0-5, or Vigoro Super Green 35-0-5 (both numbers are off the top of my head and might be a little wrong) would be great. I wouldn't recommend using anything with weed or insect control over a very wide area except in very specialized circumstances. And lastly, for most northern lawns, the optimal feeding dates are Memorial Day, Labor Day, October 1, and when the grass stops growing but is still green (Thanksgiving-ish for me in east central PA). Of those, the two most important are the Memorial Day and winterizer "still green but not growing" fertilizations, so if you choose two dates, try for those.

Agreed. Spinach is all leaf production, no fruiting or flowers so you need nitrogen. Some P and K surely won't hurt and may be beneficial to root growth. All micro-nutrients will come from good compost. Also check the label for your lawn fertilizer. In general lawn fertilizer will only contain N-P-K and no other micro-nutrients. As a general application fertilizer you want to have those micro-nutrients represented on the label too such as calcium, iron, manganese, magnesium and others.