Prepare Your Garden | Soil Testing, Preparation, and Amendments

   Soil is the foundation of a healthy garden, so it's important to check the pH and levels of nutrients before gardening. Soil testing can be done in the fall or in the spring before the lawn greens up. We offer Arkansas homeowners free soil testing.

   Do I really need to soil test?

   A soil test can make the difference between success and failure in the garden.

   Soil tests are desirable to determine the pH level and the amount of nitrogen, phosphorus, potassium and calcium in the garden’s soil.  

   They are helpful if the samples are taken properly and the recommendations followed. Your county Extension office has instructions and containers for submitting the samples.

   The pH of the soil can be adjusted to make sure that soil nutrients are available. Most native soils in Arkansas are acidic and need to be amended with lime to raise the soil pH.

   What's the best pH for Vegetable Gardens?

   The vegetable garden should be slightly acidic with a pH level ranging from 5.8 to 6.8. Lime takes 6 to 8 weeks to alter soil pH and should be applied in the fall or late winter. Agricultural lime has a mix of particle sizes and will provide long term control of soil pH. 

   Pelletized or lawn lime has very fine particles and reacts over a much shorter period of time but needs to be reapplied annually. Reduce the recommended rate if using pelletized lime.

   Liming the soil makes nutrients available to the plants, especially calcium. Gypsum can be added to increase calcium if the soil pH does not need to be raised by lime.

   What's the best way to prepare the soil?

   Arkansas soils range from coarse sands to heavy clays. Each presents a special situation to the gardener.  The type of soil is an important consideration if there is a choice.

   • Sandy loam or loam soils are well adapted to vegetable production. 

   Although sandy soils are quite workable, they do not hold water or fertilizer nutrients as well as clay soils. Adding large amounts of organic matter such as organic compost and manures will greatly improve the nutrient and water holding ability of these soils.

   • Vegetables may be grown on heavier soils if they are well-drained. 

   Heavier soils have clay particles which are smaller than sand and become quite hard. They are usually productive if managed properly.

   Amendments such as sand, finely ground bark, gypsum, vermiculite or perlite, composted organic matter and organic mulching can be added to clay soil to improve soil conditions and provide more air spaces for roots.

   Tips for Soil Preparation

   Small garden plots can be prepared for planting by using a spade, shovel or spading fork to turn the soil.  Turn the soil to a depth of 6 to 7 inches. Use a small tractor or garden tiller for larger gardens.

   Do not spade, till, plow or cultivate soil when it is too wet. Pick up a handful of soil and squeeze it. If the dirt sticks together and will not crumble after squeezing, wait until it is drier.

   All litter or trash on the soil surface should be completely covered or worked into the soil when the ground is turned. Excessive trash in the upper soil level interferes with final seedbed preparation and later cultivations. This is a good time to add compost and soil amendments such as agricultural lime.

  Establish a smooth, level surface by raking or harrowing as soon as possible after turning. This helps compact the soil, breaks up clods and leaves a smooth surface for seeding.  Soil left in rough condition for several days after turning may dry out and form hard clods, making it much more difficult to prepare a good seedbed. Small seeds germinate poorly in loose soil with clods, and growth of the seedlings may be slow and weak.

   How do I use my soil report to make amendments?

   Reading a soil report can be overwhelming, especially for new gardeners. Learn how to focus on what's most important to helping your garden grow by watching Episode 2 from the Gardening from the Ground Up Series.

   Soil Amendments

   There are different ways to amend your soil using compost, fertilizers, and/or cover crops.

   Amending with Compost

   Compost enhances the physical properties of the soil and improves the soil's tilth. Tilth refers to the physical condition of soil, especially in relation to its suitability for planting or growing a crop.  Factors that determine tilth include the formation and stability of aggregated soil particles, moisture content, degree of aeration, rate of water infiltration, and drainage.

   Some benefits of compost include:

   • Increases the soil's water and nutrient holding capacity.

   • Aerates the soil.

   • Aids in keeping roots warm in the winter and cool in the summer.

   Tips for Success

   Apply composted organic matter and organic mulching materials freely each year since organic matter content is difficult to maintain.  Use as much as 2,000 lbs. of rotted compost for each 1,000 square feet of area (approximately six inches or more).

   Organic matter that is not well composted can be very harmful since the rotting materials will compete for nutrients with the growing plants.

  Avoid applications of saw dust. Saw dust ties up nitrogen, reduces soil aeration, and can make plants more susceptible to diseases. ∆