Gardening With Confidence ™

LESSON YOUR FOOTPRINT

Confessions of a Sustainable Gardener

Part 2 – Soil

BACKGROUND

As I continued my journey to become sustainable gardener, the subject of soil came up. Not as early on as one might expect.

As a child growing up in Norfolk, VA, I believed we had good soil. This was based purely on the fact that it was easy to work and produced nice tomatoes.  So it must have been good stuff.  We did little to it except for adding fish heads and guts, and all the good stuff that comes from dressing fish for Friday night’s dinner. That was all the amendments we used. I assumed that was what everyone did, especially at the coast where it was available and catching, cleaning, and eating fish was a lifestyle.

I knew the soil was more than a propping media. I knew it needed to provide plant nutrients, but beyond that, I just assumed everything it needed was in there. We just added a few fish heads for good measure.

My soil “Ah, ha” experience, and thus the confession, came years later when I lived in the historic district of Raleigh, in the quaint neighborhood of Oakwood. We had the cutest 1905 bungalow we renovated inside and out. Again, I had the BEST soil. Anything I planted did well. Very well.

In the 1800’s, the grounds of house next door was the location of the former horse stables. My garden was the place where the horses grazed, improving the soil everyday. But then as I gardened more from beyond the perimeter of the property and up against the house, I couldn’t grow a dang thing.

I had everyone scratching their heads. We added fertilizers, speculated there was too little sun for what I wanted to grow, or environmental pollution from the car exhausts. So, when all else failed, I did a soil test.  Particularly interesting was the pH. It was 4. Well, in the big log rhythmic world of the pH scale as it relates to plant growth, that was low; very low.

I had read where lead in the soil can lower the pH.  I never verified that, but my husband, an agronomist, who only worked as one until he went to graduate school for environmental engineering, suspected it was lead too.  From where you ask?  The lead could have either leached from the house’s layers of century old lead-based paint or from years of exhaust emitted by passing cars that were powered with gasoline containing lead. Back then lead was added to gasoline to serve as an engine lubricant and as a means to increase octane.

Most likely the lead was leaching from the house, because the low pH was only around the foundation of the house. In any case, that low of a pH inhibits plants from taking up nutrients. As such, I added lime, lots of lime. Of course, this did nothing to rid the lead. That was there to stay. I knew then there could be no edible plants grown in this location.

From that day forth, in the spring of 1989, I started to pull a soil test of every area I gardened. I still do so today. A soil test is the best little test. The results will save you time, money and effort.  Even if the soil test didn’t measure lead directly, it did measure a symptom of it.  With a little deduction, conclusions were drawn.  The soil test results also told me how much lime to add to bring the soil up to around 6.5, the desired goal.

Later on, I started gardening in clay. Sticky, gooey, ooey, robust red clay. I had to figure out this notion of friable soil. Even with my lead mess, I never realized how lucky I had it up to this point.

Soil Test

Your soil is alive. Keep it that way. Soil needs to be nurtured as well. In nature, there’s a lot to feed the soil. Leaves fall, creating nature’s mulch. These decompose, adding nutrients to the soil. In our created suburban landscapes, we need to help Mother Nature out just a bit.

Our area is naturally acidic. Growing only plants that thrive in a low pH is one way to go. However, living on a typical suburban lot, amending this soil is doable. I do. Lime is used as a soil amender most years.

To replenish the nutrients to the soil, I mulch. Initially by adding composted leaf mulch to the planting hole of new plantings and with a nice 3 – 4 inches as a top dressing each year.  I apply this thickly because it decomposes quickly and settles down. The earthworms work this mulch into the soil. Earthworms are amazing creatures.

I add the mulch for more reasons than nutrient replenishment, though. The magic of mulch will be addressed in a later post in this series. These topics are all so interrelated, but also specific. With regards to mulch as it applies to the soil’s overall health, I add it to feed the soil. Mulch also moderates the soil temperature, helps retain water, and makes the garden look tidy. But specifically, for this subject of soil, mulch is added to add nutrients.

A soil test is a process by which elements – phosphorus, potassium, calcium, magnesium, sodium, sulfur, manganese, copper and zinc are measured.  A soil test also measures pH, humic matter and exchangeable acidity.  These analyses indicate whether lime is needed and how much.  A common problem is adding too much lime.  Many people don’t realize that you can add too much.  Besides being wasteful, too much lime makes nutrients such as iron, manganese, boron, copper, and zinc less available.

The reason to test your soil is to know what is needed.  This allows for application of just what is needed reducing waste and contamination from nutrient runoff.  Putting down only what is needed saves time and money. For information in NC about soil tests and their interpretation is available at Soil Test it’s free, don’t hesitate. Bookmark it. You may be surprised how often you visit.

Friable Soil

Our area has both sandy and clay soils – as in hard baked soil that needs a pick axe to crack. Or in wet years, gooey, ooey, muck.  Inside the belt line where we are, is the home of clay; just outside our boundaries, sandy soil reins supreme. Both can be made more friable with mulch – oh, yes, mulch is later. For now, we need to mention mulch to help make our soils friable. “Friable” is just a fun and fanciful term to refer to crumbly soil. Mulch will help sandy soils retain moisture and help drain clay soils.

My soil test tells me, I don’t need to add anything.  The mulch is supplying all the nutrients my gardens needs.  Yours may be different.  In either case, performing an annual soil test tells us what we need to add, if anything. If your soil test tells you to add nutrients, do so, but take the slow ride.  Build the soil slowly by adding organic matter and other natural materials, including fertilizers, if needed.  The most important thing I learned as a gardener was this:

Gardening isn’t a race – it’s a lifestyle

To determine your soils friability, take a handful and form it into a ball.  It the ball can’t hold its shape, add more organic matter,  if it leaches water, add more organic matter.  The ball should be just right.  While I’ve read one can have too much organic matter in their earth, I have yet to have those kinds of problems.

The mulch provides all the nutrients my garden needs – with the exception to lime. Again, we tend to have a low pH. I bring it up the pH some with the addition of lime. I’m OK with that. The increase in the number of plants I can grow because of it makes it reason enough.

Oh, as you can guess, we grow the prettiest BLUE hydrangeas!

My next post in the series of my journey to becoming a sustainable garden well be on mulch – Ah, the power of the mighty mulch!

Until next time…

Helen Yoest
Gardening With Confidence