If you ask ten professionals about fertilizer you are almost certain to get 10 different answers. The information below is what I have found to be effective generally throughout Zone 10 (Martin County south through The Keys.)
Commercial fertilizers are designed to make your lawn green and stimulate growth. It should be applied to achieve an objective/s: 1. Increase leaf and root growth, 2. Aid in recovery from foot traffic and pest damage, 3. Reduce and control weeds, and/or 4. Replace nutrients lost to leaching and transpiration. A soil test, often available at your county extension office will help determine the proper fertilizer to use. Based on the results the agent can recommend the best fertilizer to use.
All fertilizers have three bold numbers. The first number represents NITROGEN, the second PHOSPHORUS and the third represents POTASSIUM.
Nitrogen (N) for leaf development and vivid green color.
Phosphorus (P) for root growth and cellular function .
Potassium (K) sometimes called potash, for root development, improved winter hardness and disease resistance.
A label that reads (15-2-15) per hundred pounds contains: 15 Lbs. of Nitrogen, 2 Lbs. of Phosphorus and 15 Lbs. of Potassium (potash). The remaining weight consists of other nutrients, conditioners and fillers. Stay away from “Weed & Feed” products unless you have a uniform weed infestation. Spot treat weeds instead.
A good blend for South Florida lawns is 12-3-10 applied according to label directions in March, June and October.
Use product that is “Time-Release”, “Slow-Release” or “Controlled-Release”. Most good quality fertilizers are. The nutrients are encapsulated in spheres designed to release the contents as moisture hits the sphere over time. You will get a longer lasting response and the product will be safe to use, fewer nutrients are lost and less pollution is created. Measure your property and do the proper calculations to determine how much to use. Always follow label directions.
The University of Florida has for the last several years recommended the use of high quality PALM fertilizer as more than adequate for citrus in South Florida. Slow release 8-2-10 or 8-3-9 with micronutrients such as Magnesium, Manganese, Zinc, Iron, etc. Apply at the rate of 1/2 Lb. per foot of circumference of branch spread, starting one foot away from the trunk to just past the drip line. Apply like salt on a hamburger. Fertilize citrus every other month. Citrus trees also appreciate foliar nutrition spray as well. There are several to choose from on the market. When using these be sure to saturate the tree – top and bottom of all leaves. This spray will actually be absorbed by the leaves and trans-located throughout the tree. I spray our citrus trees with nutritional spray in March, May, July, September and November. Notice that the spraying alternates with my citrus fertilizer months of February, April, June, August and October. There is some disagreement among scientists: some say citrus do not absorb through their leaves, others disagree. I use nutritional spray on all our citrus anyway and I think it helps.
Mango Trees: Mango trees need less care than you probably think. The palm special I recommend for palms, citrus and others is best used March, June and October. Additionally, you may want to consider application of Bone Meal, Blood Meal, Phosphates and Potassium in the fall. No nitrogen at this feeding in November. Also you may want to cut down the tops of Mango trees after final fruit is harvested to create strength in the remaining tree. Another tip: harvest fruit right before it ripens and hold it inside the house for up to a week. It should ripen just fine and you won’t have to share it with the critters.
Other Trees and Plants We use the same palm special as mentioned above. Its easier to standardize on one product for the bulk of our needs. Exceptions follow:
Palms…. Use of the palm special fertilizers mentioned above is of course the main feeding. In the event of winter yellowing I like to apply some Epsom Salts that I buy at CVS. I apply it like proverbial salt on a hamburger from about a foot out from the trunk (s) to the drip line. Water it in and in about three weeks you’ll see the green-up. Takes a while depending on the size and type of palm.
African Violets……. We use MiracleGro African Violet plant food. Its a liquid available everywhere. We use an old dishwashing liquid bottle with a squirt fitting on top. Several (usually 10) drops in there with warm water and it works well to slowly squirt the mixture into the trays under the plants. We keep the plants in small clay pots with drainage trays under them. Use deep trays and place some small gravel in the tray for the pot to rest on. These little plants need good light but not strong and they need to remain at about 75 to 80 degrees F.
FrangiPani… In containers we use nutricote or any time release fertilizer like Dynamite made for container or ground plants. When they are out in the landscape they just get the palm special talked about above. This info also applies to those white Podicas that have become so popular and easy to grow.
Roses…. We use Bayer Advanced All in One Rose & Flower Care. This is a granular product that fertilizes, inoculates against diseases and provides all around protection as it feeds. Use according to label directions and get the excellent results I get. I never have to spray or dust. Never. We just dead head and watch them grow and produce flowers.
The Use of Seawater to add nutrition to trees and plants: Hesitantly, I have placed a link below on this subject. I personally do not recommend this method for fear of burning trees and plants that may be super-sensitive to salt. http://www.ctahr.hawaii.edu/oc/freepubs/pdf/SA-9.pdf