Masterful Gardening: Do you really need a soil test?
Soil testing provides a lot of information to not only farmers, but to home gardeners with small beds and homeowners who want lush, emerald green lawns.
Soil testing is easy to do, and inexpensive as well. Quite often, it will save you time and money. It provides you with the right fertilization recipe for better results and removes the guess work, that leads to the grower applying incorrect amounts of chemicals.
I have seen people pile on fertilizers, thinking more is better, without having any idea of what nutrients their soil really needs.
Overuse of high nitrogen fertilizers has been shown to cause run off, or vaporize before the lawn ever gets the chance to use it. This not only wastes your money, it causes harm to streams and rivers.
These practices can burn the lawn or can lead to a thatch problem, as well as contribute to poor root development.
Another fairly common practice here in York County is to habitually add lime to lawns in the spring, prior to applying a "weed and feed" product. Many times, this is not necessary and can actually harm the lawn. This is because lime raises the pH of the soil.
Most turf grasses will thrive in a slightly acidic soil, with a pH between 6.1 and 6.9. Around 6.5 most nutrients are readily available to the roots. If the pH has become too high, from the addition of unnecessary lime, then phosphorus, iron, manganese, copper and zinc becomes less available to the plant.
On the other hand if the soil is too acidic, aluminum and manganese can concentrate at toxic levels. It is always easier and less expensive to test the soil, rather than repair damage.
I have never used lime on my lawn and found it strangely interesting that my soil test came back with my pH being slightly alkaline and in need of nitrogen and phosphorus. In my individual situation adding lime would have been a big mistake.
On the contrary, if I would have over applied large amounts of phosphorous, this surely would have compromised the plants ability to absorb iron. So you can see how important a properly balanced fertilization plan can be.
Another interesting fact is you will need fewer pesticides when plants are grown in ideal soil conditions. A healthy, properly fertilized lawn prohibits the growth of weeds and disease in both lawns and gardens.
Testing may be done at any time, provided the soil is not frozen. For vegetable or annual flower gardens, it is always better to test prior to planting. Obviously, if you have an established lawn or perennial bed, this is not possible.
But you can still test and amend the soil accordingly. Vegetable gardens, flower beds and lawns all have different requirements for growing healthy plants, so each area should be tested separately.