Horticulture News

DATE: September 24, 2007

HARDIN COUNTY COOPERATIVE EXTENSION SERVICE
201 Peterson Drive
Elizabethtown, Kentucky 42701-9370

BY: Amy Aldenderfer
County Extension Agent for Horticulture

Benefits of Fall Soil Sampling

True or false? Spring is the best time to take soil samples.

False. Fall is the optimum time to take soil samples for fertility analyses.  Time and money are among the reasons to do fall soil sampling.

Fall sampling gives you plenty of time to follow fertility recommendations before planting season.  As soon as you receive the soil test results, look at the recommendations for pH, a measure of soil acidity that affects plants' uptake of all nutrients, and for lime.  If the soil pH is too low, it decreases the uptake of essential nutrients, and elements like aluminum and manganese can become toxic to growing plant roots.

Applying limestone neutralizes soil acidity. Because agricultural lime takes about six months to break down and react with the soil, it should be applied in the fall to be fully effective in the spring.  Unlike fertilizer, lime is needed every three to five years, depending on your crop rotation and nitrogen fertilizer history.  The only way to determine if your gardens will need lime next year is by soil testing this fall.

A common complaint is that it took the laboratory too long to return the results.  The turn-around time is much faster in the fall, usually within a week of submission, in the fall because fewer people are submitting samples. This is another reason fall soil sampling saves time.

All the recommended fertilizers, except nitrogen, also can be applied this fall.  Often a fall application will save you considerable money because fertilizer prices generally are cheaper in the fall as a result of garden centers clearancing items.  In addition to lower fertilizer prices, it's easier to get the spreader in the garden during the fall because the soil is drier.

Gardeners who don’t soil test can only guess at the fertility needs of their gardens, and far too often their assumptions are wrong. Guessing at the amount of fertilizer to apply often results in applying more than the recommended rate.   Some gardeners want to be sure there's plenty of fertilizer available in case they have a bumper crop next season.  However, studies have shown that crops need the same amount of fertilizer in a good year as in a poor year.

If you're interested in collecting fall soil samples, stop by your local county Hardin County Extension office.  We can give you details on how to take accurate soil samples and where to send the collected cores. 

Remember, spending some effort on soil sampling this fall can keep you from wasting time and money.  Fall soil samples also can provide big returns for next year's crop because you won't be relying on a guess of your gardens' fertility needs.

Educational programs of the Cooperative Extension Service serve all people regardless of race, color, age, sex, religion, disability or national origin.