Slow and Steady Wins the Fertilizing Race

Walking into a garden store to pick up some fertilizer for the first time means that you've been confronted with the extensive and befuddling array of choices. If you are not familiar with the nutrient needs of your plants and the type of soil you have, selecting a fertilizer becomes a laborious process of reading labels and hoping for some divine insight.

In the search for fertilizers focus on two main distinctions: fast-release fertilizers and a category that contains both slow-release and controlled-release fertilizers. The fast-release variety is typically found in forms like liquid, soluble crystals or granular fertilizers, which disperse the nutrients all at once. Slow-release and controlled-release fertilizers disperse their nutrients gradually, over a period of time. Slow-release fertilizers expel their nutrients in a less predictable manner than controlled-release. In slow-release fertilizers the release depends on the activity of organisms in the soil, while controlled-release fertilizers do exactly what their name implies-release the material at a specific rate over a specified period of time.

Generally no one fertilizer is going to meet every gardening need, but selecting these types prevent the common problem of inundating plants with nutrients, which typically occurs with fast-release fertilizers. When nutrients are released all at once the roots of the plant are inundated, and then the fertilizer is washed away by rains or watering, and the roots are left with no nutrients. It is also easy to apply too much of a fast-release fertilizer and do severe damage to your plants. Using slow- or controlled-release fertilizers makes it difficult to inflict this type damage on your photosynthesizing friends.

In addition to harming your plants, fast-release fertilizers can pollute groundwater since the excess that is not absorbed by the plant washes off of lawns and gardens and into the water table. Since the plant absorbs the slow or controlled-release fertilizers, little or no fertilizer is carried away into the water table.

In general, fertilize plants and lawns just before they begin their grow cycles. This typically occurs in the spring through the fall. From fall to spring you can probably reduce or eliminate fertilizing. Check with local cooperative extension programs to find out the best time to fertilize in your area, as well specific tips about which fertilizers will provide the best nutrients to work with the soil in your geographic area.

Sources used in this article include Warren Davenport, National Gardener's Association, www.nga.org; and VirtualGarden.com, www.vg.com.