Last year I installed a rose bed in my mother's garden in North Carolina, which now consists of about 35 roses. Last week she asked me to suggest a fertilization program, and to write it down for her. I wrote out the following, and thought I would post it here in case anyone should find it useful:
Here is my advice for fertilizing your roses. But before explaining the regimen that I recommend, allow me to give you some background information that will help you understand why I recommend one approach over another.
At the most basic level, there are several types of fertilizers:
1. Dry all-organic fertilizers derived from natural components like composted manure, bone meal, blood meal, feather meal, alfalfa, sea bird guano, bat guano, etc. My favorite product is Peruvian Seabird Guano.
2. Wet all-organic fertilizers (such as Neptune brand concentrated fish emulsion)
3. Dry synthetic chemical fertilizers (such as Miracle Gro time-released pellets)
4. Wet synthetic chemical fertilizers (such as Miracle Gro liquid concentrate, or dry granules that are mixed with water)
5. Combinations of organic and synthetic dry fertilizers combined as a single product (like mostly organic Rose -Tone by Espoma)
6. Combination of organic and synthetic wet fertilizers (combined as a single product, such as Mills Easy Feed liquid)
Nearly all fertilizers have a “guaranteed analysis” of their Nitrogen (N), Phosphorous (P), and Potassium (K) content. For example, the N-P-K numbers for Rose-Tone fertilizer are 4-3-2, which means the contents of the fertilizer are comprised of 4% nitrogen, 3% phosphorous, and 2% potassium. Nitrogen contributes to overall growth and foliage. Phosphorous contributes to root growth and blooms. Potassium contributes to disease resistance.
In general, most organic fertilizers will have lower N-P-K numbers than synthetic fertilizers. Even though synthetic fertilizers are cheaper and more potent, I only recommend using mostly organic fertilizers (options 1, 2, 5, or 6 above) for the following reasons:
• Organic fertilizers feed and enrich the soil, which then feeds the plant, whereas synthetic fertilizers just feed the plant. As an analogy, you can liken the use of organic fertilizers to eating an apple, whereas the use of synthetic fertilizers is like eating a packet of sugar. The apple isn’t as fast-acting as raw sugar, but over the long-term, apples contribute to a healthier diet.
• Ironically, synthetic fertilizers can damage garden soil over time by saturating it with salts that can eventually “lock up” the soil and prevent plants from being able to absorb nutrients. There are even products to “leach” fertilizer salts from garden soil after they build up over time.
• Some organic fertilizers provide micro-nutrients and minerals that are essential to plant health.
• Some organic fertilizers contribute to the presence and health of beneficial microbes in the soil. By contrast, high-acidic synthetic fertilizers can be fatal to earthworms, which are an important contributor to the health and structure of garden soil.
• Synthetic fertilizers are more likely to wash out of the soil during rain (with the exception of time-released versions), whereas organic fertilizers mixed into the soil can have more staying power.
• Synthetic fertilizers tend to produce run-off residues (especially nitrogen) which find their way into creeks, rivers, lakes, and wetlands. This is creating a growing problem in the environment. High nitrogen robs water of oxygen, increases algae, and can lead to the death of aquatic organisms.
With all of this in mind, I think option 1 or 5 above is a relatively easy and environmentally conscientious approach. (Options 2 and 6 are good, too, but for large gardens involve careful measuring and the use of siphoning equipment. I do that, too, but won't go into that since Options 1 and 5 are easier to start out with, in my opinion.)
If you go with Option 1, I suggest that you buy a 25 pound bag of Pelletized Peruvian Seabird Guano from the DirtWorks website at
http://www.dirtworks.net/Bat-G.... It is an economical fertilizer with an unusually high Nitrogen and Phosphorous content for an organic fertilizer, and is slowly released. Pellets can be used once for the entire growing season. For established plants use one tablespoon of pellets scratched into the top three inches of soil, a few inches away from base of the plant, and then watered in.
If you go with Option 5, my suggestion would be to purchase Rose Tone fertilizer by Espoma (or any other mostly organic fertilizer recommended by your nursery), and follow the dosage directions on the bag. Sprinkle 1 ¼ cup of Rose-Tone around the base of each established rose. Use a garden fork to work the fertilizer into the top 3 inches of soil, then water the soil around each plant. This regimen should be followed on a monthly basis between April and August. Stop fertilizing (and stop deadheading) after Labor Day, to allow the roses to slow down their blooming and gradually “harden off” in time for the onset of cold weather. If you keep fertilizing and deadheading after Labor Day, the roses will not be as resistant to cold weather once it arrives. If you go with this option, buy your fertilizer in the largest bag you can find (e.g., 40 pounds). The bigger the bag, the cheaper it will be by the pound.
Ideally, I would combine Option 1 and Option 5 during the month of April (for North Carolina), because it will take time for the Seabird Guano to “break down”, and in the meantime the powdery Rose-Tone can get to work. In other words, when you put down the Seabird Guano, also put down a cup of Rose-Tone at the same time. But you won’t have to repeat the Rose-Tone applications on a monthly basis because the Seabird Guano will do the job during the remainder of the growing season. This is what I do.
Additional micro nutrients can be added with liquid products such as OceanSolution, or Age Old Kelp, to name a few examples.
