Improving Soil with Compost

Using Compost to Improve a Soil

Adding compost to a soil does two things; it changes the physical structure of the soil and adds plant nutrients to it as well. The question becomes, “Does your soil need it?” Sometimes it does, sometimes it doesn’t. Learn to know if your soil needs compost or not before buying it.

This 2 inch layer of Viragrow compost will be dug into this soil about 6 to 8 inches deep. The soil will then be shaped into raised beds. It will last for about two years until more is added. Depending on the crop grown, fertilizer may or may not be needed for several months to a year.

Improving Soil Structure

Compost changes the physical structure of the soil. This can be a good thing when its needed or it can be unnecessary if its not. By adding compost to a soil it improves water drainage in soils that don’t drain water easily.

Soil drainage and aeration is improved because of the improved soil structure created by compost.

But, like a sponge it also holds water in a soil before it drains making it available for the plant to use. Mixing the right amount of compost into a soil can be tricky. You want the soil to drain water, but you also want it to hold water for plant roots.

At some point, when you find that balance between draining water and holding water, adding more compost to it is throwing your money down the drain…literally! Find the amount of compost to add and then stop! Add enough compost every year to maintain the ideal balance for the plants you are growing.

Plant Roots Must Breathe

Plant roots must “breathe” or they will suffocate and die. Adding more compost to a soil increases its “aeration” or the admission of “good” air full of oxygen into the soil and the releases of “bad” air from the soil. Some plants need more compost, or aeration, in the soil surrounding their roots than others. For instance, lawns and palms tolerate lower amounts of aeration in the soil while roses, flowering bedding plants, most vegetables and many ornamental trees and shrubs need more aeration.

Plugs or cores taken from a lawn improve drainage and root aeration which causes roots to grow deeper. This is mechanically doing what compost does naturally!

The amount of compost to add depends on which plants you are growing. But ALL plants tolerate aerated soils. Know the plants you are growing and add compost to soils when its needed.

Using Compost as a Fertilizer

Compost improves a soils structure for better drainage and it can add nutrients as well. The question becomes, “How much to add?’ The answer may surprise you. It depends.

A circle of rich compost such as Viragrow's can feed plants by releasing its plant nutrients. The compost remains in place to slowly improve the soil surface where feeder plant roots like to grow.

Some composts are “rich” in plant nutrients while others are not. Remember the old saying, “Garbage in, garbage out.” This is very true of compost. Compost can be very rich in plant nutrients when made from animal manures. Sometimes it can be so rich in nutrients that it must be applied carefully to avoid plant damage. Compost made only from plants is usually less “rich”. But both types of compost improve the soil physical structure which is enough to improve plant growth. Compost made from animal manure may have enough plant nutrients to stimulate plant growth for months! Plant leaf color and growth will tell you when plant nutrients are needed again. 

How to Fertilize with Viragrow Compost

Viragrow Composts are "Rich" Composts

Viragrow Composts...all three of them...are considered "rich composts". Thats not true of all composts. Viragrow compost is unique in that regard. They are full of plant nutrients.

• Viragrow Compost (aka, 166) 
• Viragrow Premium Compost 
• Viragrow "Organic" Compost (aka, Vegan)

The Viragrow Compost, for instance, contains about $140 of plant nutrients if you were to buy them seprately from the compost. That is, they contain a lot of nutrients because of how they are made and the ingredients used.

In the case of fruit trees, amending the soil around plant roots with Viragrow Compost at planting time may mean no additional fertilizer is needed for two years after planting!

Viragrow Compost (aka, 166) contains about $140 in plant nutrients in each cubic yard

Not all Composts are "Rich"

For instance, the Viragrow Compost contains about $140 of plant nutrients in each cubic yard if you were to buy the plant nutrients as fertilizers separately. Other composts may work well as a soil amendment but they will not add this amount of "fertilizer" to the soil. Plants respond to these plant nutrients by growing faster, larger and darker green.... full of nutrients.

Viragrow's "Organic" Compost (aka Vegan) is made without any animal products or by-products.

Compost is a Slow Release Fertilizer

The plant nutrients in compost are "slow release"... they are released slowly over time as the compost "dissolves" into the soil. Eventually these nutrients are exhausted, along with the compost, and more compost needs to be applied. It depends on the plants but more may need to be added once a year or less often. Mineral fertilizers may need to be added several times a year with other composts.

Water dissolves plant nutrients in the compost and makes these nutrients available to plants. We know it as "compost tea".

Adding Compost Does Not Change Soil Volume

Adding compost to a soil may make the soil volume larger for a short time but eventually the soil settles and returns to its normal volume. The soil becomes darker because of all the "organics" left behind in the soil. That's a good thing. The darkness is a healthy visual indicator that you are bringing "life" into the soil. A healthy soil means healthy plants.

All of the composts and soil mixes are tested in Viragrow's Garden area at our yard. These vegetables are not fertilized for about three months after they are started.

Different Plants Require Different Amounts of Compost 

It is important to "feed" plants with the right amount of nutrients so they are not over or under fed. Plant feeding has much to do with how deep their roots are and how quickly they produce what you want.

Underfeeding plants gives you small amounts of growth and production. Large amounts of compost may damage or overstimulate plants into "luxury consumption" where they may not be healthy and withstand harsh desert conditions.

Type of Plant          How Often Fertilizer   How Often Compost
Vegetables               Monthly                        Once
Lawns                     Every 6 to 8 weeks         Twice a year
Fruit Trees              Once or twice a year       Every two years
Landscape Trees     Once a year                    Every two years
   and Shrubs                           
Roses and               Four times a year           Twice a year
   Flowering Shrubs