Mark's intrigued by the idea of hydroponics, but I'm pretty leery. The more I read about micronutrients, the more I feel like there may be micronutrients out there that plants need which we can't provide. I have a gut-deep but entirely unsupported feeling that the food we buy in the grocery store lacks important micronutrients, and that in turn makes people who subsist only on grocery store food less healthy. The soil is a huge reservoir of who knows what, but are we really smart enough to replicate it?

Of course, my aversion could just be that I really, really like to dig around in the dirt.

Such nutrients are only needed in minute quantities. It shouldn't be too hard to add sufficient of them to a hydroponics feed solution?

At least in hydroculture you know and control what you feed your plants. Without chemical analysis, how are you going to tell what if any micronutrients are missing from the soil on your farm?

You can easily add the micronutrients that you know exist. But we're still in the infancy of understanding soil and plant biology --- check on this post I made about how many plant micronutrients there are, and note that we only discovered the most recent one about twenty years ago. Who's to say there aren't another few out there that we aren't aware of?

In organic gardening, micronutrient deficiencies are less common, and the gardener can usually figure out what's going on by noticing signs like yellowing leaves. Most micronutrients are naturally occurring because of weathering of the bedrock, and you can use judicious applications of dynamic accumulators to add specific ones.

All of that said, I'm pretty sure Mark's going to get his way and try hydroponics before too long, if only to try to grow a few small veggies inside in the winter.

It might be too expensive for an individual, but it shouldn't bee too difficult to get a groundwater and soil sample from a place where plants grow right, and analyze that with a mass spectrometer or gas chromatograph? Then you'd know exactly which elements are in there and in which proportion, down to the parts-per-million range. Of course that is not a complete picture (it doesn't tell you about which molecules these elements belong too), but is that so difficult? Can plants actually absorb solids? I'd think that they can only use whatever is dissolved in water? I'm not a chemist, but a lot of the micronutrients I saw were metals, which tend to dissolve in to water as ions (from salts).

As for nutrients deficiency in store-bought food, I think that's a small problem. People in the western world now live longer on average that ever before. A couple of years ago they cleared out a graveyard in the centre of Eindhoven that had been in use from around 1300s to the late 1800s. IIRC, the average age of the remains discovered there was in the mid-thirties. The average life expectancy now in the Netherlands is around 80! (of course hygiene and proper healthcare play a large role in that next to proper nutrition). One could argue that we might be reaching the limit of what our bodies as evolved up to now can reach without major genetics engineering. So while our diet could be improved, it's historically not half bad. We just eat too much of it. My employer makes medical scanners, and my department builds patient supports for x-ray and MRI machines. Currently, we have to build these to hold a 600 lb patient! Our bodies didn't evolve to be that heavy. That's a much bigger problem, I think.

I like the idea of analyzing the groundwater, but I'm not sure it'd give you the entire picture. Sure, plants can't absorb solids (I don't think), but the associated fungi and bacteria often can, then can give some of the nutrients to the plants' roots. I'm blanking on specific nutrients right now, but there are some that bind to organic matter in the soil and are only made available to plants when fungi disentangle them and trade them to plants for sugars.

I think that our current weight gain as a species could possibly be due to micronutrient deficiencies. Couldn't people be eating much more food than they need because the stuff they eat doesn't have the nutrients they need? If that were the case, I could see our bodies telling us, "eat more!" even though we had plenty of carbohydrates, fats, and proteins. But I have absolutely no data to back this part up...

That would only make sense if we could detect deficiencies in micronutrients in our diets. And I don't think we can. That is, we can detect it by the consequences (e.g. scurvy for vitamin C deficiency etc) but not before without resorting to external aids like blood tests. Of course we feel hunger, but I suspect that's rather a high-level thing (like your blood sugar dropping, or your stomach being empty), and not specific as to the nutrients involved.

What I've read (and think it makes sense) is that humans evolved in an environment where food was relatively scarce and took a lot of effort to gather and prepare, conditioning us to eat as much as possible, sotring the excess as fat. The fact that abundant food is available (at least in developed nations) coupled with a sedentary lifestyle and the way we evolved equals trouble.

Erich --- I've also seen really good arguments for overeating being linked to psychology. If we're just craving more sugar, how do you break the cycle?

Roland --- of course the same micronutrient argument applies --- do we really know every micronutrient the human body needs?

I'd definitely buy what you said about us evolving to be constantly searching for food. I wonder if there's a way to channel that constant searching into something more productive?

We definitely don't plan to jump to growing all of our own grain immediately, but I think it would be feasible to work up to that point over the long run.  I did the math, and it would take about a fourteenth of an acre to grow our own grain, which would mean expanding our garden by about a quarter.  That's a lot of extra work, but if we can work out a suitable rotation like Fukuoka's do-nothing farming, I think we could definitely fit it into our long term plan.