Master Gardening Class #1b: Soils

Having vented my fill yesterday  (and everyone else's) about how hard I found it simply to get to the class at all, much less with the right chapter under my belt, I shall turn to the far more trivial matter of what actually went on in this class, and what I learned.

The class reviewed the components of good soil—minerals in various sizes (sand, silt, and clay) organic matter, air, and water. I was familiar with this, and with the importance of soil aggregates (clumps) that leave spaces within which air, water, and roots can move. For many people the shocker is that organic matter should comprise only 5-10% of the soil.

But for me it was the graph quite indicated that in an ideal soil fully half the volume is taken up by air and water. That's right: 25% each. If I'd learned that before, I'd forgotten it.

We also went over plant nutrients, how the primary six cycle through soil, water, and sometimes air, and the symptoms of various nutrient deficiencies; soil pH and how it influences nutrient availability; and fertilizers and soil tests. All in under two hours.

For me, the tough part came when we were asked to translate a soil science report into a concrete recommendation. In other words, we had to work out how much of a particular fertilizer to recommend for a particular sized garden given a particular level of deficit. In other words—graphs and algebra. In other words, not words at all, but numbers. Ack!—

I'm ashamed to say that I could feel panic hovering just over the horizon. Our instructor, Clain Jones of  MSU's Dept. of Land Resources and Environmental Science, was quite aware that some of us might find it “too late in the evening” as he put it for math; I think that was actually one of the choices on a the quiz questions, which was a nice touch.

There was one point at which I did take issue with both the text (when I got around to reading the right chapter) and the lecture: during their overviews of the advantages and disadvantages of organic and synthetic fertilizers, both left out what I consider to be some of the significant advantages of organics: that unlike synthetics, they aren't made from petrochemicals; that they're less likely to damage soil organisms than synthetics; and that aside from manures, they're less likely to lead to a build-up of toxic salts in the soil.

You will all be happy to hear that I arrived at class tonight (approximately) on time, with the text, with paper, with a pen, and with a marginally working acquaintance of the subject matter. However, I did not have a syllabus until I found one at the class; the one I'd downloaded turned out to be for Level I. Ah well; one mustn't be too picky.

10 Responses to Master Gardening Class #1b: Soils

  1. Hi,
    I have a quick question about your site. Would you mind emailing me back @

  2. Thanks for a great post on soil. I didn’t realize that compost should be such a small part of the composition. I had been aiming for more of a 50/50 blend, so I’ll have to rethink that.

  3. The Nebraska extension here has a weekly tv program on PBS (which is housed literally across th street from extension). They always push chemicals and fertilizers, and it frustrates me–I even wrote to them a few times about it with no response. Poor unsuspecting saps watch the program and think it’s ok to dump stuff and spray stuff like nobody’s business. And I wonder now, does extension push these ideas because they know the demographic and the 1950s they come from, so don’t want a fight?

  4. Welcome, Judy. A lot of people made a similar and unnecessary effort. Too much compost won't generally cause problems in a flower or vegetable garden, but it can in landscaping. I'll post more on this soon.
    Awesome fibers on the site of yours!
    Welcome to you, too, Melissa, and good luck with that pesky, interfering, weed-murdering neighbor of yours.
    Beats me, Benjamin. I think sometimes that extension grows from and extends the norm. I'm not sure yet. I hope not. The other end of the same circle, if you can follow me round it, is the number of extension sites that promote compost tea, which has almost no science behind it. Go figure.

  5. Very interesting post. As far as the percentage of organic matter in the “ideal” soil, I think it should be 25%. It should be balanced with minerals, air and water, in other words 25
    % each (at least for what I have learned in a soils class). In South Florida we got very bad soils, mostly limestone, so the 25 % organic matter may apply to only us. Anyways, I am glad I have found your blog!

  6. That’s fascinating, Jorge. I consistently see and hear 5-10%, so I’m startled to hear about a soils class that recommends more. If you remember the context, please share it! I’m glad you found this blog as well.

  7. Great blog as usual Kate! I can sympathise with the panic attack over graphs and algebra – that brought back fearful memories of school; stepping into the maths class and feeling those large, thick, steel doors clanging shut in my brain! Shivers down the spine! Still, I enjoyed reading about your class and it’s great that you’re sharing all this with us.

  8. Thanks, Wendy. The weird thing for me is that I’ve actually enjoyed math in the past, and took it past calculus in college (doing increasingly poorly, it’s true.) But this was classic math anxiety. Numbers, Ack! Run! Go figure.

  9. After us the same place to plant year after the can get depleted of the minerals to grow a good garden. Do you need to move to another location or add different matter to soil.

  10. Good info about the soil. I learned that all soil is organic in their own way. What we have to do is add lots of organic matter, compost, manures and shredded leaves to the soil to improve it.

Leave a Reply

Your email address will not be published. Required fields are marked *