Tuesday, November 13, 2012

Test That Soil!

Ok, so it took a while to get started on soil basics for vegetable growing but lets get going with it and then we'll move forward into some more detailed gardening information for the Permian Basin over the course of the next few weeks.

To begin growing veggies, you need to understand what kind of soil you have and that can only be done properly with a soil test performed by a laboratory.  A soil test will give you an idea of the texture or parent material of the soil in which you'll be growing vegetables. There is little you can do to immediately change the texture.  Most West Texas soils are somewhat sandy but heavily composed of limestone which was deposited, according to the experts that spend a lot of time figuring out this kind of stuff, millions of years ago.  Its going to take a little time to improve the soil texture and this is done by amending the soil with organic material.

Please note that texture can't truly be changed without digging all of the soil out and starting over with lots of new soil from some alluvial (mineral rich deposits from flowing water) source and that's simply not practical.  The solution is to use lots of composted organic material which is the topic of the next blog.  For now lets just stick to foundational reasons to start your gardening with a soil test.

The test will also give you an idea of its pH and fertility.  Soil pH is a measure of soil acidity.  Soils with a high pH are called basic and are common in the Permian Basin.  As you can see by carefully examining the graph below, basic soils, or those soils above a pH of 7.0, begin to tie up iron, manganese and zinc.  The higher the pH, the greater the reduction in the availability of these nutrients no matter how much is in the soil.  Iron is a particular problem for development of healthy and productive vegetables since it's a primary component in chlorophyll.  Iron deficient plants often exhibit symptoms of yellowing between the veins of leaves.  This is known as interveinal chlorosis and leads to a lack of carbohydrate production by the plant and poor development or perhaps in extreme cases, starvation of the plant to the point of dying.

Dead plants can't grow veggies so what's the solution?  Many people add chelated iron to the soil but this is temporary.  Most astute gardeners add amendments and grow vegetable varieties that are tolerant of our pH (another topic we'll fold into the blog soon).  Some vegetable growers use fertilizers that help decrease the pH but again this is temporary and the effect is limited.

So for now, just start with an understanding of what kind of soil you have by getting it tested.  You'd really, really be surprised by how rarely this is done.  A lot of folks go out and spend their hard earned dollars on plants from the local nursery and plug them into the ground without any knowledge about their soil.  A soil test is a must.

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