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,