Growfood.com » Soil, Fertilizers & pH

Soil, Fertilizers & pH

Following is an important primer on soil (there will be a quiz, called life in the garden, so pay attention and take notes!):

Soil is soil, and the functions of soil are simple, as follows:

1. Provides anchorage and protection for plant roots.

2. Holds water and oxygen for plant use.

3. Acts as shelves to hold water-soluble minerals for plant use.

4. Acts as a temperature regulator.

5. Affords drainage for plant roots.

There are three main types of soil, including sandy, clay, and loam, and many variations between these, depending on the presence or absence of sand. Loamy soil is half way between heavy clay and straight sand, and is considered ideal for most growing.

Sandy soil drains quickly and does not hold nutrients well. It can be improved by adding clay soil. Clay soil drains poorly, and is difficult to work in. It can be improved by adding sand.

Thousands of years of leaching, erosion, and crop removal have left most soils all over the world deficient in water-soluble (available) plant nutrients, therefore supplementation is necessary for healthy and fast vegetable plant growth. They don’t have time for natural processes to change non-soluble minerals into water soluble forms, the way a tree or perennial bush does.

The soil “tilth” or structure and workability (ease of working) of soil can be improved by adding organic materials.

You should not, however, count on organic materials to give you the balanced nutrition your plants need, because leaching, the cow, etc. have taken much of the minerals out, and no-one can tell you what or how much of anything it still has in it.

And you should beware of the very real likelihood of bringing diseases, bugs, and/or weed seeds into your garden by introducing organic materials, such as compost and manure, into the garden.

Clean, disease, bug, and weed-free plant residue from your own garden can be incorporated back into the soil to good effect. However, unless you have a proper composting facility and the time and commitment to compost aerobically (which requires 140+ degrees, 24 hours per day for 3-4 weeks), you should just till plant residues immediately back into the soil, where they will compost naturally and not attract pests and diseases.

Beyond that, just use a small amount of sand to cover your seeds and fill cracks that appear in clay soil, and use the Mittleider Magic natural mineral nutrients to supply the balanced natural mineral nutrition your plants require for fast and healthy growth.

No matter where you are in the world what I’ve said above applies. Simple isn’t it?!

The other thing you need to understand is soil pH, and that too is quite simple, but you will need to pay attention, and maybe print this out.

Ideal plant growth is achieved at a soil pH of 6.5-7 (close to neutral). If you receive more than 20” of annual rainfall your pH will be below 7, and the more rain the lower the pH. Why? Because rain leaches the nutrients (especially calcium, potassium, and magnesium) out of the soil, lowering the pH.

How do you raise the pH into the ideal range – and replace the nutrients? The calcium in lime (calcium carbonate), is an essential plant nutrient, plus it raises soil pH, so applying lime to the soil is essential. Potash and magnesium are also helpful on both fronts. And of course we also apply all of the other essential nutrients to our soil. But lime is the most important one for raising soil pH.

If you receive less than 20” of annual rainfall your pH will be above 7. Now what do you do – you still need the nutrients but you don’t want to raise the soil pH. You still give your soil the essential calcium, but you use gypsum instead of lime. Why? Because gypsum has almost equal parts of calcium (raising pH) and sulfur (which lowers pH), and it is therefore pH neutral.

You also use potassium sulfate in your Weekly Feed, rather than potassium chloride. And if your pH is very high you might need to add some supplemental sulfur.

That’s it – now you know what you need to regarding soil amendments! Aren’t you glad you asked? At least you don’t have to worry about adding tons of sand, manure, or compost to your soil. And you can have a great garden in any soil, in virtually any climate.

And you don’t have to search for any red worms, bacteria, microbes, etc., etc., to “feed your soil”. Those are only necessary to help organic materials decompose, so that organic minerals can revert to the water-soluble mineral state in which they are available to plants!

If you have learned the above you have passed the first section of my horticulture 101 class. Congratulations!