Welcome to our soil science information page.

Soil is not just dirt.

 

Great vegetable gardens come from great soil. So, what makes the soil great?

 

1. Minerals from sand, silt and clay, 45%*

 

2. Water, 25%

 

3. Air, 25%

 

4. Organic material, 5%

The biggest particles in soil are called sand. The clay particles in the soil are very small and have an electrical charge. The size of silt is between sand and clay. Sand allows water to drain, silt is fine enough to create small spaces for air, and clay holds water and nutrients. If there is too much sand, water drains out too quickly and plant nutrients are washed away. If there is too much clay in a soil, the water cannot drain out and plant roots suffocate from lack of air. Loam soil is a good mixture of the three.

The percent of sand, silt and clay give the soil its texture. (See the Soil Triangle.) To discover the texture of your soil, click on the button below to follow the flow chart.

SOIL CHEMISTRY: What is pH and why is it important?

The way plants take up nutrients is through chemical reactions that take place in the water around the plant roots. pH is a measure of the acidity or alkalinity of this water in the soil. The best garden soil is slightly acidic. The range of pH goes from 0 to 14 where 7 is right in the middle or "neutral." Values less than 7 are acidic, values greater than 7 are alkaline. The best soil for vegetable gardening is slightly acidic with a pH measure of 6.5. At this level, plants can take up the most nutrients. Click on the button to learn more.

SOIL BIOLOGY: Who lives in the soil?

 

Great soil also needs the animals that live there!

  • Worms and bugs start the decomposing process.

  • Microbes are the recyclers of organic matter that work on a very small scale to create the nutrients plants need to grow and reproduce.

  • Fungi work with plants to help them get these nutrients from the soil.

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Seed Saving
Sat, Sep 14
1401 S G St
Sep 14, 2019, 11:00 AM – 12:00 PM
1401 S G St, 1401 S G St, Tacoma, WA 98405, USA
You liked what you grew in the garden this summer and would like to grow it again. Come learn at the end of the growing season how to save and store seed. This applies to some fruit, many flowers and most vegetables.
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All Things Fig
Sat, Sep 07
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Sep 07, 2019, 11:00 AM – 12:00 PM
1401 S G St, 1401 S G St, Tacoma, WA 98405, USA
Grow figs at home – in the ground or in a pot on your deck. You will learn about types & varieties that grow well in the PNW. You'll learn what soil to use, how & when to fertilize, watering requirements, different types of pruning, how to make fruit ripen earlier, and when to pick.
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Tomato Tasting
Sat, Aug 24
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Aug 24, 2019, 11:00 AM – 12:00 PM
1401 S G St, 1401 S G St, Tacoma, WA 98405, USA
Come enjoy a taste of the Gallucci tomato harvest! Enjoy tasting and discussion of the many different types of tomatoes we're growing. Varieties will include Sungold, Orange Paruche, Black Krim, Little Napoli, Bloody Butcher, Slava, Stupice, Brandywine, Chocolate Cherry, and Fourth of July.
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Introduction To Your Soil
Sat, Jul 27
1401 S G St
Jul 27, 2019, 11:00 AM – 12:00 PM
1401 S G St, 1401 S G St, Tacoma, WA 98405, USA
Bring a gallon of your DRY soil to GLG to explore structure, texture, pH, nutrients and soil biology. Participants will gain a general understanding of soil types, try home test kit analyses, and discuss fertilizers and amendments to improve their soils.
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Energy and Environment
Sat, Jul 13
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Jul 13, 2019, 11:00 AM – 12:00 PM
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Learn the basics about Renewables, Energy Efficiency, and Green Building, and gain helpful insights to making your home and community more sustainable.
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Overview of Small Fruits and Berries
Sat, Jun 29
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Jun 29, 2019, 11:00 AM – 12:00 PM
1401 S G St, 1401 S G St, Tacoma, WA 98405, USA
Bill Horn, Western Cascade Fruit Society and Pierce County Master Gardner, will discuss the grow methods and care of local small fruits and berries.
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1401 S G St
Tacoma, Washington 98405