Home Vegetable Garden Guide

Soil Preparation

The last step in planning your garden is soil preparation.

Good soil is key to the success of any vegetable garden. Once you have located and designed the perfect garden location, you will need to examine the soil as well as have it tested for nutrient levels in order make amendments needed for successful plant growth.

Get to Know your Garden Soil

The secret to a healthy plant and a lush, productive garden is in the soil. A good soil regime and healthy plant will ward off most disease, decrease bad pest population and create a balanced environment.

Soil acts as a reservoir to hold water for plants.  Water is one of the most important elements for a plants survival because it stimulates the roots for nutrient uptake, is a primary factor in photosynthesis, as well as a carrier for food transportation, and temperature regulation.

Soil moisture content, drainage, and aeration are critical for plant growth and health.

 

Soil Composition

 

 There are several different types of soil commonly found in the United States.

 

Clay
Fertile soil with tightly packed small particles that retain water with slow drainage and poor aeration.

Sandy
Large particles that retain the least water and nutrients due to rapid drainage and good aeration.

Silty
Moderate fertility with medium sized particles that retains some water and nutrients with poor drainage and poor aeration.

Loamy
Ideal soil for gardening! Perfect mix of sand, silt and clay. It has good aeration, adequate water and nutrient retention and drainage.

Testing

Most local county offices can advise you on testing the soil in your area. The results of the soil test will indicate the pH (acid-alkaline balance) of the soil as well as the nitrogen, phosphorus, and potassium content. The necessary nutrient levels are relative to the soil type and the crop being grown, so be sure to inform the laboratory that you are growing a vegetable garden to get the proper recommendations. Although different vegetable plants have varying requirements, the soil test institution calculates an optimum average for recommendations.

 

Amendments

So what can you do if you are stuck with not-so-great soil? Unfortunately, except by adding in large amounts of soil, there is really no way to change the soil. You can, however, use it's natural advantages and compensate for it's challenges by working on the soil structure with organic matter.

Although loam is a mixture of 40% sand, 40% silt and 20% clay, adding sand to your clay soil, or clay to your sandy soil, will not create loam. Actually in doing this, it will result in something like cement. Creating a loose, loamy, fertile soil is an ongoing process that involves working organic matter into the soil, every year.

This solution is a three step process including organic matter, soil organisms and rotary-tilling.

Organic Matter
It's good practice to incorporate organic matter each year while preparing the soil no matter what type of soil you have to help with fertility. The addition of organic matter is particularly important if you have sandy or clay soils. It will make the clay soil drain better or sandy soil hold more water in addition to providing valuable nutrients.

Soil Organisms
Earthworms, beetles and other critters tunnel through the soil naturally areating and fertilizing the soil through their digging and castings. The tunnels create open spaces in the soil allowing air, water and roots to pass through easily.

Rotary-tilling
Compacted soil makes it difficult for roots to push through and grow. Tilling the soil breaks up compacted soils and changes the soil structure producing the base for a ready-to-plant garden bed. It also makes mixing amendments in much easier, especially in larger areas, and removes weeds. There are disadvantages to rotary tilling every spring as it can kill the soil organisms in the area that naturally areate and fertilize the soil, bring humus to the top layer of the soil and destroy it with too much air exposure and bring dormant weed seeds to the surface.

 

Correctiong the Soil pH

The pH number is important because it affects the availability of most of the essential nutrients in the soil. The pH can be adjusted using lime or rock sulfur. Below are recommendations to use as general guidelines.

*** Remember to always following manufacturer specific recommendations when using any chemical.

To increase the soil pH by 1.0:

Hydrated Lime per squared yard Soil Type
4 oz Sandy
8 oz Loamy
12 oz Clay
25 oz Peaty

To reduce the soil pH by 1.0:

Ground Rock Sulfur per square yard Soil Type
1.2 oz Sandy
3.6 oz All other soils
Please note: The correction of an overly acid soil should be considered a long term project, rather than trying to accomplish it with one treatment. It is better to test your soil each year and make your adjustments, gradually increasing the pH. The addition of hardwood ash, bone meal, crushed marble, or crushed oyster shells will also help to raise the soil pH.

 

Final Soil Preparations

The soil should be crumbly, but slightly moist. Spring soil can sometimes be too wet to plant seeds or seedlings in. Test your soil to see if this is the case by squeezing a handful of soil. It should break apart into smaller clumps. If it clings into a ball, it is too wet and compacted, and you will need to wait for it to dry a bit more before planting. Test again in a day or so.

When ready, use a tiller or hand tools to turn and loosen the soil to a depth of 8 to 12 inches. Working in any amendments directly in the planting area in your furrows or raised beds can be accomplished quite easily at this time. We highly recommend working compost and fertilizer at least once a year during this time. Remove clumps of grass, roots, stones, lumps and assorted debris that accumulated over the winter.