What is Soil?  Or as I like to call it- DARK DIRT

Soil is made up of 4 components – minerals, organic matter, water and air. The mixture of these 4 ingredients determines the soil characteristics. Good soil…

  • supports plant roots
  • retains moisture
  • provides nutrients to the plant
  • creates air pockets


Minerals in your soil are simply broken down rocks. They are hard and supply grit. If you looked under a microscope you would see tiny grains of sand and/or specs of clay and silt all mixed together. These soil minerals vary in size and the balance between the sand and clay gives soil it’s basic structure.

Soil is made up of 4 components – minerals, organic matter, water and air. The mixture of these 4 ingredients determines the soil characteristics. Good soil…

  • supports plant roots
  • retains moisture
  • provides nutrients to the plant
  • creates air pockets


Soil that has a lot of clay will hold moisture well but will have little oxygen for the plants to use. Clay is made up of very small dense particles that are packed together. Water will have a hard time flowing through clay. It is also very difficult for tender plant roots to grow in heavy clay soils. The fact that water often pools in heavy clay soils means plant roots sit in water which many plants do not tolerate well.

Soil that has a lot of sand will be lighter, but water will run through it quickly as it has limited ability to retain moisture and nutrients.

Ideal soil will be a mix of sand and clay. This is often referred to as loam. There will be enough support offered by the clay and a light airiness provided by the sand to support the roots.  The tiny clay particles will slow down the water as it passes through, however the large sand grains ensure water does not become trapped.




What This Means for The Gardner

The structure of your soil will not change unless you do something to alter it. If you have very clay based soil you will want to add sand in order to create space between the tiny clay particles. If all you have is sand, you are going to want to add clay. Fortunately, most soil is already a combination of clay and sand. You may have pockets that require a little attention and that can usually be remedied by adding additional topsoil. Screened topsoil can be purchased by the bag or the truck load, depending on your need.

The good news is no matter what you have to work with all soil can be easily improved by adding organic matter. The more the merrier!


Organic matter

For plants to thrive soil must contain organic matter. Organic matter will feed the microorganisms, help water move through the soil and add air pockets to the soil structure. Organic matter is continuously being consumed by the organisms in the soil. Therefore, it is very important to continually add organic matter to the soil.

These two dirt samples have the same basic structure.  The difference is the amount of organic material they each contain. The soil on the left is lacking organic material. When I try to form into a ball by squeezing it in my fist, it will not hold together.

The sample soil on the right has been supplemented with compost earlier in the season and supports healthy plants. You can see that when I squeezed it in my fist the dirt formed a ball and held together. It is still crumbly and breaks apart easily, but it has a better structure due to the organic material.


The proof is in the plants

These two kale plants were started at the same time.

The first one, that is about half as tall is the boot, grew in the soil with very little organic material.


The second kale plant, which is easily twice as tall as the boot, grew in the soil that had been enriched with organic material earlier in the season. I have been harvesting leaves off this plant for the past 6 weeks!


What This Means for The Gardner

When I first built my gardens, I purchased topsoil by the truck load and built beautiful perennial gardens. Once planted, these flowers came up year after year. After several years I noticed my plants were not growing as vigorously or blooming as well as they once had.

I made the mistake of not supplementing by adding organic matter to this flower bed. You will often hear gardeners talk about ‘top dressing’ their flower beds with compost.  This means spreading 2-3 inches of compost over the flowerbed at least once a year. This adds organic matter as well as introduces organisms that help the plants grow. The good news is it is never too late to start.


Soil needs Decomposed and Decomposing Organic Matter

Organic matter that is completely decomposed is called humus. It is soft, fluffy and holds water and air pockets. Organic matter that is partially decomposed has the microorganisms and nutrients. If you look at a compost pile and you can tell that a little bit of material was once part of an apple, then it is partially decomposed. Finished compost is nature’s balance between partially decomposed and completely decomposed organic matter.

It’s important to have a mixture because the microorganisms or bacteria, as they continue to feed on the material, give off acids and enzymes that help plants grow. These enzymes work with the plants roots to fix nitrogen and to take up phosphorus, iron, and other nutrients. This is the good stuff that plants need to thrive!

When you mix this living organic matter with your soil (clay / sand mix) you get a structure stable enough to support the plant roots while allowing room for the roots to grow. This dirt is also full of many rich organisms that spread through the soil and help plants grow.


Stable Organic Matter

Organic matter is considered stable if it is completely decomposed. The most natural example of this is leaf mold. On its own leaf mold does not have enough structure to support plant roots. It contains no minerals to give nutrients to the soil. Yearly layers of decomposing leaves support a variety of fungi and organisms that help breakdown the leaves.

What This Means for The Gardner

In one of my gardens, where plants were not thriving, had only stable organic matter. There was no active organic matter for the organisms to feed on. The soil looked nice, but it was all leaf mold, peat moss, completely decomposed straw and perlite. It was fluffy but there were no nutrients and enzymes. It could barely retain water and with no mulch or additional fertilizers it simply could not provide the nutrients that the plants needed to thrive.

In order to fix this soil, I added a huge amount of aged manure, shredded leaves and compost. This combination provided the organic matter that the microorganisms needed. As they work and continue to breakdown the organic matter, they will give off the enzymes and nutrients needed by the plants.  Over time the earthworms will return which will also improve the soil.

As I continue to garden in this bed, I will add fresh compost before I plant new seeds.  By doing this I am adding new microorganisms and organic material continuously to the soil.

Link to pictures and video of the new raised bed and the plants as they grow.


Video  in Soil folder – soil types demonstrated.mp4

Anyone can go to the store and buy a fertilizer and throw it on a plant and hopefully see positive results. Honestly, the big companies want you to buy their fertilizers and soil enhancers. Knowledge is power and if you understand the natural process, you will have the power to grow great flowers and vegetables without breaking the bank on supplemental fertilizers or other products.

Soil PH Explained

pH is designed to measure soil acidity or alkalinity.  Soil pH is extremely important because it directly affects how a plant can make use of the nutrients in the soil. It is measured on a scale from 0 -14.

Most of the plants we grow perform best in a soil that is slightly acidic, usually within a pH range of 6.5 to 7.

We all know that acid breaks things down but too much acid will destroy things. This same principal holds true in your soil.  A slightly acidic soil will breakdown the ions making the nutrients available for the plant roots to absorb. If your soil is too alkaline, over 7 on the PH scale, it won’t be able to breakdown the ions and there won’t be enough nutrients to feed the plant.

Most typical garden plants grow in the 6  –  7.5 range, however there are a few plants that are more particular and have a narrow tolerance range. Below is a chart identifying common plants that grow at different PH levels.

If you currently have a garden and find certain things thrive while other plants are impossible to grow you have some clues about the pH balance of your soil. Lilac (6.0-7.5) grows well for me and blueberries (4.0-6.0) are very sad in my garden. Potatoes (4.8-6.5) do okay but not great.  This tells me my soil is more neutral to alkaline, likely 6.5-7.5.

If you live on the west coast and azaleas bloom like crazy and hydrangeas thrive you know you likely have more acidic soil ( 4.5 – 6.0 range)

Scan through the list and you will likely see a pattern which will give you an indication at the pH level of your soil.

Trees and Shrubs pH Range
Apple 5.0-6.5
Ash 6.0-7.5
Azalea 4.5-6.0
Basswood 6.0-7.5
Beautybush 6.0-7.5
Birch 5.0-6.5
Blackberry 5.0-6.0
Blueberry 4.0-6.0
Boxwood 6.0-7.5
Cherry, sour 6.0-7.0
Chestnut 5.0-6.5
Crab apple 6.0-7.5
Dogwood 5.0-7.0
Elder, box 6.0-8.0
Fir, balsam 5.0-6.0
Fir, Douglas 6.0-7.0
Hemlock 5.0-6.0
Hydrangea, blue-flowered 4.0-5.0
Hydrangea, pink-flowered 6.0-7.0
Juniper 5.0-6.0
Laurel, mountain 4.5-6.0
Lemon 6.0-7.5
Lilac 6.0-7.5
Maple, sugar 6.0-7.5
Oak, white 5.0-6.5
Orange 6.0-7.5
Peach 6.0-7.0
Pear 6.0-7.5
Pecan 6.4-8.0
Pine, red 5.0-6.0
Pine, white 4.5-6.0
Plum 6.0-8.0
Raspberry, red 5.5-7.0
Rhododendron 4.5-6.0
Spruce 5.0-6.0
Walnut, black 6.0-8.0
Willow 6.0-8.0
Asparagus 6.0-8.0
Bean 6.0-7.5
Beet 6.0-7.5
Broccoli 6.0-7.0
Brussels sprout 6.0-7.5
Cabbage 6.0-7.0
Carrot 5.5-7.0
Cauliflower 5.5-7.5
Celery 5.8-7.0
Chive 6.0-7.0
Cucumber 5.5-7.0
Garlic 5.5-8.0
Kale 6.0-7.5
Lettuce 6.0-7.0
Pea 6.0-7.5
Pepper, sweet 5.5-7.0
Potato 4.8-6.5
Pumpkin 5.5-7.5
Radish 6.0-7.0
Spinach 6.0-7.5
Squash, crookneck 6.0-7.5
Squash, Hubbard 5.5-7.0
Tomato 5.5-7.5
Alyssum 6.0-7.5
Aster, New England 6.0-8.0
Baby’s breath 6.0-7.0
Bachelor’s button 6.0-7.5
Bee balm 6.0-7.5
Begonia 5.5-7.0
Black-eyed Susan 5.5-7.0
Bleeding heart 6.0-7.5
Canna 6.0-8.0
Carnation 6.0-7.0
Chrysanthemum 6.0-7.5
Clematis 5.5-7.0
Coleus 6.0-7.0
Coneflower, purple 5.0-7.5
Cosmos 5.0-8.0
Crocus 6.0-8.0
Daffodil 6.0-6.5
Dahlia 6.0-7.5
Daisy, Shasta 6.0-8.0
Daylily 6.0-8.0
Delphinium 6.0-7.5
Foxglove 6.0-7.5
Geranium 6.0-8.0
Gladiolus 5.0-7.0
Hibiscus 6.0-8.0
Hollyhock 6.0-8.0
Hyacinth 6.5-7.5
Iris 5.0-7.5
Lily-of-the-valley 4.5-6.0
Lupine 5.0-6.5
Marigold 5.5-7.5
Morning glory 6.0-7.5
Narcissus, trumpet 5.5-6.5
Nasturtium 5.5-7.5
Pansy 5.5-6.5
Peony 6.0-7.5
Petunia 6.0-7.5
Phlox, summer 6.0-8.0
Poppy, oriental 6.0-7.5
Rose, hybrid tea 5.5-7.0
Rose, rugosa 6.0-7.0
Snapdragon 5.5-7.0
Sunflower 6.0-7.5
Tulip 6.0-7.0
Zinnia 5.5-7.0

Adapted from https://www.almanac.com/plant-ph

Testing your Soil

You can purchase a test kit at your local home/garden center or take a sample to your county extension office for professional testing. The at home test usually costs about 25$ and includes everything needed to perform multiple tests for each of four different factors: pH (acidity/alkalinity), nitrogen, phosphorus and potassium.  The best time to do a soil test is the fall. You can then work any necessary amendments into the empty garden, as well as plan for the fertilization needs for the coming year.

How to Increase your soil Acid level


If your blueberries are dying like mine, you need to increase the pH level of your soil. Acidity can be raised by adding sulfur. You will not need very much as a little goes a long way.

The most common way to increase acidity is to work peat moss into the soil. Do not plant directly into soil freshly amended with peat moss. Wait until it has been thoroughly moistened and allowed to absorb water.

Mulching with pine bark, pine needles or cedar chips can provide additional increases in acid levels.


What to Do if Your Ph Level Is Too Acidic

Amending the soil with limestone will reduce acidity and promote the spread of good bacteria by supplying critical nutrients like phosphorus and zinc to the soil. This means you can fertilize your garden more effectively, saving you money in the long run.

The best way to determine your soil pH and any necessary amendments is to submit a soil test sample to your local Cooperative Extension  Office.  Contact the office for instructions. When submitting a soil sample, make sure you specify what crop you intend to grow, since different crops require specific pH levels. You will receive a report noting your soil pH, and the type and amount of additive to correct any problems. The best time for a soil test is the fall. You can work the additive into the empty garden, as well as plan fertilization needs for the coming year.

Additional Soil Amendments for Specific Needs

In addition to adjusting soils pH balance soil amendments increase the plants ability to hold moisture,  and add essential nutrients needed by the plant.

Wood Ashes: Wood Ashes reduce acidity and supply soil with lime and potassium. Often used for root crops, roses and peonies.

Bonemeal: Bonemeal is often used to add phosphorus and nitrogen to the soil . It will not affect acid levels and is typically used for flowers with large blooms such as roses and dahlias

Gypsum: Gypsum will increase calcium levels in soils that are deficient but do not require any change in pH balance

Manures: Composted animal manures have been used for centuries. They not only add nutrients, but they also condition the soil.

Perlite: Perlite is a long lasting, porous soil amendment made from heated volcanic rock which has been  broken into small granules. It is often added to potting soils or raised beds to increase water retention and lighten the soil.

Seaweed: Like manure, seaweed is a great soil conditioner that also provides valuable nutrients. It can be used directly as green manure combined with compost, or used as a mulch

Straw : Straw is often used as a soil conditioner mixed with maneuvers. It can also be an effective mulch to reduce weeds along pathways, however, it often contains unwanted weed seeds.  Caution should be used when introducing it directly onto a garden bed.

Vermiculite: Vermiculite is similar to perlite but it is derived from Mica. The granules are slightly larger and also contain some trace nutrients

Worm castings: Earthworms are a welcome addition to any garden and worm castings are prized by gardeners, particularly for nourishing young seedlings . Worm castings contain rich concentrations of mineral elements.

Soil is a vitally important aspect of gardening that is not always glamorous and can be easily overlooked. Spending extra time and attention learning to understand your soil and the needs of your specific plants will pay great dividends at harvest time.

Composting is one of the best things you can do to continuously take care of your soil and make awesome DARK DIRT that will grow beautiful flowers and nutritious, tasty vegetables .