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                                                                    Soil Amendments



Perhaps you lived in a part of the country where “The Perfect Soil” existed, but if you live in Idaho you will quickly find out that our soil is anything but that.  However, turning poor quality soil into plant friendly soil is not all that difficult to do.  It just takes a little knowledge and some effort to accomplish this task.

Most soils in the Treasure Valley consist of some form of organic material, water and air. Creating a good, plant friendly soil requires humates (Natural Guard ‘Humic Acid’) and depending on the soil, various other amendments to enhance the soil.  So what is a humate?  Humate is the highly compress and biodegraded remains of ancient plants and animals. In the soil, humates enhance the capacity to hold and exchange mineral nutrients with plant roots.  They also promote greater absorption and utilization of nutrients applied to foliage.  As they are organic and high in carbon, humates and humic acids buffer and reduce the phytotoxic effect chemicals contain when applied.  Let me expand a little further by saying that humates are neither a fertilizer nor a biostimulant.  Keep in mind that humates are not a quick fix to repairing a problem lawn!  Humates are organic soil conditioners that appear to be like a biostimulant by increasing microbial activity in sod, thus producing the long term results you are looking for.


Why do we start by stating that Soil Activator is important?  Natural Guard ‘Humic Acid’ is a humate and plants will not live and thrive without them. Not all humates are the same.  VPG, the company that produces Natural Guard Soil Activator states that some humates contain as little as 15% of a living microorganism.  Natural Guard 'Humic Acid' is derived from the finest sources of humates in the United States and is superior to any other brand on the market today.  One last thought on humates, they do not replace fertilizers and other products necessary for the care of your lawn, they simply cause most products to work better when applied to your soil.

Soils are typically classified by soil particles (ex; sand, silt and clay).  The amount of sand, silt and clay will determine the consistency of soil and its ability to absorb and retain nutrients, which will in turn reflect in part, the performance of your plants.

Most all soils as we perceive them are composed of a percentage of organic matter.  Organic matter consists of leaves, grass clippings and other vegetative material.  These organic elements are important to plant life.  They give the soil its ability to bind together, yet remain porous enough to intake water and air as well as the ability to store the necessary nutrients necessary for plants to live. You can add organic material to our soil by composting leaves, grass clippings, small twigs, vegetable scraps and other material.  We recommend not composting tree branches, wood chips, and bark as it not only slows the process of composting, but may rob nitrogen from the soil.
Of course, plants require more than humates and composted material to live and thrive.  The soil must include bacteria, fungi, nematodes, mites, earthworms, insects and other small creatures.  These tiny creatures are required to convert organic matter into the necessary elements that plants need to survive.  Along with these essential elements, we must include air and water in the appropriate amounts.  Most gardeners don’t realize that air is a source of atmospheric nitrogen and that the percentage of air in the soil should be approximately 25% for earthworms, insects and other soil borne life forms to survive.

Essentially, small clay particles are great at holding nutrients in the soil, but lack the ability to absorb moisture and maintain the correct amount of air.  On the other hand, large particles such as sand provide plenty of air, but do a poor job at retaining nutrients.  Our long-term goal should be to create a healthy plant environment and to employ long lasting amendments in the soil.  Some gardeners find that the use of organic amendments increase organic matter and last somewhat longer than many inorganic materials.  In time, organic matter will increase water retention and also increase the soils ability to maintain its nutrient holding ability. 

It’s sometimes necessary to provide short-term relief to the soil, especially when plants are showing signs of stress.  This can often be done by choosing the proper fertilizers to incorporate into the soil.  Not all fertilizers are truly good or beneficial for our soil.  Take the time to know and understand how the different nutrients effect the plants you are caring for.

Where to begin...If you are in doubt of the condition of your soil, it might be advisable to take a sample to Western Labs in Parma, Idaho.  They can determine the pH of the soil, the salt content and determine what elements may be needed to ensure healthy plant development.  Before taking a sample to them, we recommend calling them.  There are certain things that are required to perform an accurate analysis of your soil.

Not all plants require the same soil amendments, but nearly all plants thrive and do well if we follow these general guidelines.  Composting with manure, a good soil conditioner, Canadian peat moss, perlite or vermulite, and mixing these amendments with your existing top soil which will certainly increase a plants ability to perform as it should  (for any amendment to perform as it should, it must be thoroughly mixed with all other components including the existing soil).

We use these amendments when planting perennials, annuals and most shrubs and trees in our area.  In this article, we mentioned that not all humates are the same and that also applies to soil conditioners. 

Breaking down the amendments…An amendment is any material that is added to the soil that will improve its physical quality.

Some so-called “soil conditioners” are nothing more than a bag of bark.  As a certified nursery professional, we use and recommend Happy Frog ‘Soil Conditioner’ or Ferti-lome 'Ultimate' Potting Soil along with a few other quality soil amendments.  These products are manufactured by companies that produce outstanding soil conditioners.  The price may be slightly higher, but when compared to the quality, they are really cheaper products.  Having been in the landscape and nursery industry for over 47 years has given us the knowledge and ability to recognize and sell quality products. 

We made reference to Canadian peat moss.  That’s because there is truly a difference between Canadian peat and American peat.  Canadian peat is acidic whereas American peat tends to be neutral to slightly alkaline.  In our Idaho soils, it’s very important that we use Canadian peat to lower the alkalinity of our soil.
We recommended manure in our list of amendments.  In the list of manures, the most common is steer manure and the second most common in our area is chicken manure. The most important thing to remember is whether the product is aged and composted.  Raw steer or chicken manure is often to “hot” to place on or around plants and can “burn” the plant, often doing extensive damage.  Aged steer or chicken is typically safe to use around plants and in the vegetable garden.  We use Oakdell 'Composted Chicken Manure' and have found that you can actually plant directly into it, although that's not recommended, mostly because of the cost.  There are of course, other manures available that are quite good.  The one that comes to mind that we often recommend for small areas is “Bat Guano”.  It’s an outstanding product and is available from Foxfarm, the same company that produces the soil conditioner we mentioned above (you will find bat guano in their soil conditioner).

  Another product that we recommended is perlite or vermulite.  The most important difference in these two products is the color of the product and most importantly, at least in our area, the price.  Perlite is off white in color and vermulite is brown/tan tones, making it nearly impossible to see.  If you can live with the color, we certainly recommend perlite.  We also mentioned the price; it’s nearly twice the cost of perlite with no real added value that we can see.

Choosing the right products...When we refer to top soil, we are referring to your ‘existing” soil.  Occasionally, you may wish to add soil to your garden.  Our recommendation, make sure it’s “top soil” and not fill dirt which typically has no living microorganisms or other nutrients necessary for plant development.


Soil amendments are not regulated in our area, especially when purchased in bulk.  Some may contain high amounts of salts, especially amendments involving livestock.  We certainly like “mushroom compost”, but it is often very high in salts, making it very important to mix this product with other amendments as well as soil.  This statement is also true of “raw” bagged steer manure.  Wood composted amendments are low in salts, but as we stated above, wood based amendments require additional amounts of nitrogen to break down the product.  Wood based products are great as a top dressing (bark mulch) in the landscape.  It gives landscape beds a clean, finished appeal, however its not the best when using as a planter mix.  At times you may find products that state they are soil conditioners or top soil.  Read the label!  If you buy a bag of top soil and can easily pick it up with one hand, it most likely NOT top soil.  It may have as small amount of top soil mixed in so as to make it legitimate.

Essentially there are two types of amendments.  One is organic and is derived from a living plant or animal and the other is inorganic, an item that was either mined or created by a manufacturing process.  Don’t get us wrong in thinking that there is anything wrong with either product.  Some mined products such as ‘Soil Activator’ (organic) is an outstanding product and ‘bark mulch’ (organic) when used incorrectly may not be the best product for the intended purpose.  Each product must stand on its on merit for its intended usage.  When amending the soil, there are many factors to consider, but we hope this will help you to become a successful gardener. 


You might also refer to our ‘Planting Instructions’ on planting shrubs and trees.  We offer them free of charge to anyone purchasing  shrubs or trees from us and they are available for a nominal charge otherwise.


Digging in the soil
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