Build Soil

I've been pretty busy lately.  I have been doing some gardening, but it's been everything else that has kept me from writing about it.  I have a number of posts to write or finish writing, but in the meantime I wanted to share part of a poem that I found recently.  It's called "Build Soil" by Robert Frost.  Unfortunately, it doesn't have much to do with gardening or horticulture, but there are a few choice lines that I will share with you.  Enjoy, and I hope to be back writing later this weekend.  Thanks!

...Plant, breed, produce,
But what you raise or grow, why feed it out,
Eat it, or plow it under where it stands
To build the soil.  For what is more accursed
Than an impoverished soil pale and metallic?
What cries more to our kind for our sympathy?

For the whole poem, click here.

Soil Drainage Test

How well does your soil drain?  This is an important question - it could mean life or death for your plants!  If your soil has too much clay, it could remain waterlogged, keeping oxygen from getting to plant roots.  If it is too sandy, water and nutrients drain right through the root zone.  Here's how to find out how well your soil drains:

First, dig a hole about a foot deep.  Fill with water and let it drain completely.

Immediately refill the hole and measure the depth of the water with a ruler.  Fifteen minutes later, measure the drop in the water level in inches and multiply by four, to calculate how much water drains in an hour.

What is your soil's drainage rate?
If it drained between 1 and 6 inches per hour, then you have well-drained soil.  If your rate was less than an inch per hour, your soil has poor drainage.  If it drained more than six inches, your soil has excessive drainage.

What does this mean?  What do I need to do?
If your soil has poor drainage there are a few things you can do.  Amending the soil with compost or other organic matter will help with drainage as well as adding nutrients.  You can also choose plants that tolerate wet conditions - there are many native plants that work well - hibiscus, bog lilies, pitcher plants, and many others.

Adding organic matter helps soil with excessive drainage as well.  If the area gets a lot of sun, you may want to consider growing succulents.  There are a number of aloes, agaves, yuccas and cactuses that are hardy in your area.  Also, once established, native flowers like Rudbeckia and Echinacea can thrive in areas where drought-tolerant plants are needed.

With the right information, there's no need to let plants grow in a soil that's not right for them.

How To Get a Soil Test

One thing that everyone should do before planting their garden, or even landscaping their yard is have the soil tested.  I have to admit that I had never done this - until last year.  Here's how you do it.

You need to get a representative sample of the area that you want tested, which means you should collect a dozen samples and combine it into one composite sample.  Soil samples should be collected from the surface to 6-8 inches deep.  Using a soil tube or auger is pretty straightforward, but if you are using a spade or trowel the technique is a bit different.  Dig a v-shaped hole about 6-8 inches deep and use your trowel or spade to take a thin slice from the side of the hole.  Combine all the soil samples in a clean bucket and mix them thoroughly.  You'll need at least two cups of soil per sample.  You can either take your sample to your local Clemson Extension office or purchase a soil sample mailer.

 About a week after I dropped off my soil samples at the Clemson Extension office, I received an email with a link to the results of my soil tests.  I had two different soil tests done - one for the vegetable garden and one for the beds in the front yard.  When you fill out the forms, it helps to let them know what you plan to plant and whether you want organic recommendations as well.  I thought I asked for both, but I only got inorganic recommendations.  Here is what the chemical analysis of my soil looks like:

The soil test found low levels of potassium; phosphorus and calcium levels were very high, which is common for this area.  To correct the potassium deficiency, it was recommended that I use muriate of potash.  Since I didn't get organic recommendations, I tried to learn more about these fertilizers and amendments, to understand what they were and what the organic alternatives were.  In general you can tell what an amendment is by the fertilizer grade.  I knew muriate of potash (MOP) was solely to correct the potassium deficiency, since the third number was so high, but I decided to read more.  MOP is actually potassium chloride and there are a lot of people out there that think it's harmful to soil biology, but others say it leaches out of the soil fairly quickly - and supposedly chloride increases yield by improving disease resistance.  Since I wasn't a fan of chlorine, I decided to see what my options were - it turns out that there are few.  Sulfate of potash is a common substitute, but it tends to be more expensive and it has less potassium (0-0-50), so you need more of it.  It is used for plants that are sensitive to chlorides.  An organic alternative to these are wood ashes.  They may contain around 6% potash, but they also contain lime which raises the pH of the soil, making it more alkaline.  There's no easy way of knowing how much potash is in it and, if you don't need lime, you shouldn't use it.

The other fertilizers are pretty straightforward.  10-10-10 is what it seems like and it turns out 15-0-15 is a common fertilizer for centipede grass.  I haven't looked into organic alternatives to these, but it seems easy enough.  Maybe it won't be in one product, but I'm sure there are things out there that are good substitutes for this.  That will have to be a future blog post.  For more information about soil tests, click here:

HGIC 1652 Soil Testing