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Nov 29

Soil: How Sweet It Is

Posted to MMWD Blog: Think Blue Marin on November 29, 2016 at 11:38 AM by Ann Vallee

by Dan Carney, Water Conservation Manager

How would you describe the soil in your garden: sandy, loamy or gumbo? Whatever the texture, it should be teeming with beneficial organisms ranging in size from squirming earthworms to microscopic fungi. As many as 1 billion bacteria can live in a teaspoon of soil according to the U.S. Department of Agriculture. That’s a lot of life!

Healthy soil supports a complex food web, where nutrients are recycled and made available to your plants. Investing in your garden soil is like investing in a healthy diet and exercise—it helps you live a long and happy life. 

For example, think about a time when you tasted a homegrown tomato or sweet corn that was bursting with flavor. Besides being delicious, they were packed with nutrients that came right out of the soil. 

When you are planning a new Marin-friendly landscape or food garden, consider getting your soil tested. It’s an easy way to find out about the pH, nitrogen balance and overall health of your soil. You can buy a do-it-yourself testing kit for as little as $20, or send your soil sample off to a professional testing laboratory for around $50. Here’s what you need to do:
  1. Go to the Marin Master Gardeners Gardening Resources webpage, under “Soil & Compost,” and find the testing solution that works best for you. 
  2. Follow the package or laboratory’s instructions on how to collect the soil samples. Typical collection instructions go something like this: 
    • With a hand trowel and one-quart zip-lock bag in hand, dig down 4-6 inches below the soil surface and scoop up a dozen small samples from different areas of your garden. Fill the bag about half full and mix the samples together.
    • If you’re sending the sample to a lab, tightly seal and label the bag and mail it as soon as possible. If you’re testing it yourself, just follow the instructions on the test kit.  
One advantage of sending the sample to a lab is you can ask for recommendations on the type and quantity of amendments your soil needs. Keeping your soil in top condition will help your plants grow stronger with less water, produce tastier veggies and fruit, and reduce pest and disease problems. It costs a few dollars more and is well worth it. 
Jul 15

A Living Sponge

Posted to MMWD Blog: Think Blue Marin on July 15, 2016 at 11:53 AM by Ann Vallee

by Charlene Burgi

For most of us, sponges are something we typically think of as an aid to washing cars or dishes. Some people might envision the sponges that live in the depths of the ocean. But how many consider their soil a sponge—or even a living sponge?

sea sponge
Sea sponge. Photo courtesy of
Dr. Rick Tegeler (a friend since
junior high school days)

You might say that is a stretch, or argue that sea sponges are animal while soil is mineral. But don't forget the build-up of humus typically composed of mulch, decomposed plant and animal matter, and other organic material that we add to our gardens. Through our actions, we can create sponges in our gardens as beautiful and alive as oceanic sponges.

This lesson came to light for me last week as I left Lassen County behind and headed for the great Northwest. Everywhere I went I found pristine lakes and rivers as well as dense vegetation. Wild tiger lilies sprouted up and bloomed along the glaciated trails where I meandered.

The forest floor
Another living sponge:
the forest floor

I noticed the forest floors where I walked gave way with the weight of my steps. It was as if I were stepping on thick, damp sponges. The soil was teeming with life directly underfoot! Plants flourished in this rich environment.

As I walked, I thought of how my own garden had the same quality of sponginess. Last year, my beloved late husband Jack used bags of hydromulch (left over from a landscape job) in the garden walkways. That project last year made for an amazing regeneration of plant material this year. Petunias are now growing wild where that thick layer of hydromulch was spread. Tomato and squash seeds are popping up as if to create a forest of their own. The garden is as alive as the soil that supports it.

Wild petunias
 Volunteer petunias
In addition to supporting healthy plant life, the benefits of creating that living sponge in your garden include water retention. Water is absorbed, held, and released slowly to the root systems of your plants. Organic material in that sponge-like soil also releases nutrients that support the beneficial fungal mycorrhizae that the root systems of plants depend upon.

Creating a living sponge in your garden can be as simple as adding compost material and organic mulches in thick layers. (You may even qualify for an organic mulch rebate from MMWD.) Over time, as with the forest floor that I trod upon, the soil will take on a sponge-like spring as you walk upon it, and plants will flourish as you have never seen before.
May 06

Soil Woes? Compost to the Rescue!

Posted to MMWD Blog: Think Blue Marin on May 6, 2015 at 1:12 PM by Ann Vallee

by Christina Mountanos 

 Sharpei contributing to soil compaction issues
My shar-pei contributing to soil compaction issues
I have to admit there are several areas of my garden that I’ve been neglecting over the past few years. The biggest problem? Hard, lifeless soil. The worst is an especially unattractive, narrow area next to my back fence.

What bothers me the most about this particular area is the rate of infiltration (how quickly water enters the soil). It’s incredibly slow. Countless times last year I can recall hurriedly trying to hand water the area after a long day at work, literally drowning the poppy seedlings there while impatiently waiting for the pooling water to soak in. No matter the setting on my shut-off nozzle, it seemed, I found myself constantly stuck in the same routine: flood, wait, repeat.

Fortunately, I was motivated to make a change after attending a Bay-Friendly Landscape & Gardening training and learning about organic compost. Prior to the training, I was already familiar with soil amendments and how they can improve water-holding capability; however, it wasn’t until I learned about soil and compost in much more detail that I became rather excited about the process.

Firstly, what makes good soil? What makes it different from dirt? The difference is simple, yet impactful: life. More than just a collection of granular particles, good soil is teeming with all kinds of living organisms, bacteria, and fungi—an entire ecosystem, really. All these organisms work together to decompose organic matter, fix nitrogen from the air, and ultimately release nutrients into the soil, which plants then use to grow and thrive. By amending your soil with organic compost (which contains organic matter), you’re essentially feeding these creatures. In turn, nutrients vital to plant health are made available for uptake by the plants.

 soil critters
 Soil critters
Good soil also has lots of holes in it (called pore spaces). Pore space is vital to good soil because it provides a place for air, water, and roots to go. It’s also responsible for water-holding capacity. From a biological perspective, increasing pore space can again be connected back to microorganisms. As these creatures process organic matter throughout their lives (and as they die), something called “humus” is produced. Humus is a magical substance that binds to soil particles and improves structure. In the case of clay soil, where the particles are very tiny and often pressed together tightly, humus helps create more pore space between them.

In my particular problem area, I knew two things: I wanted a relatively drastic change and, after receiving the last bit of winter rain, I had to get to work before the soil started meeting the Medusa-like gaze of the afternoon sun again. For unplanted areas (like mine) that haven’t been amended previously, or aren’t regularly amended, organic compost can be dug down and mixed into the native soil. The back of the bag I purchased suggested 6-8 inches, but my local nursery encouraged me to dig the compost down as far as I could.

For established planting areas where it’s best to avoid disrupting the root zone by digging, compost can simply be layered on top of the existing soil just like mulch. Such an application would ideally be done in the fall to let winter rains naturally distribute the nutrients down into the native soil, but really any time of year is a good time for compost! Water from irrigation and worms will slowly distribute the organic material down into the soil, too, just more slowly. For reference, one 2-cubic-foot bag of compost will cover a 12-square-foot area, 2 inches deep. (Good news: MMWD's organic mulch rebate includes compost, too, meaning you can get up to $50 toward your purchase.)

However you choose to do it, adding compost to your landscape is quick and easy. It’s the ultimate remedy for a wide variety of problems, a fix-all for soils that absorb water too slowly and also for soils that may fail to hold water well at all. Improving the rate at which soil accepts water means less water wasted to runoff. Soil that retains water for longer periods of time means having to water less often. And don’t forget that at the root of these qualities is life. Fostering it results in both improved plant productivity and water conservation. You won’t be disappointed.

Happy spring,