Green Industries Best Management Practices manual

• Enhancing foliage color and plant appearance;• Correcting or preventing nutrient deficiencies.RECOMMENDATIONS AND BASIC PRINCIPLESFOR FERTILIZING LANDSCAPE PLANTSThe recommendations in this section do not pertainto products containing insecticides, herbicides, orother pesticides. By law, such products are consideredpesticides. For-hire applicators must be licensed andthe label instructions must be followed (see Chapter 6on pest control for more information).Important recommendations and principles for fertilizinglandscape plants are as follows:• Prior to fertilizing, a soil and/or foliar nutrient analysisshould be used to determine whether any need existsfor phosphorus fertilizer.• Before fertilizing, pests may need to be controlledand/or soil modified to improve nutrient uptake orplant responses to fertilizer.• Plants with pests or other problems that could increaseto damaging levels with fertilization should be fertilizedonly in conjunction with a treatment program. Withouta treatment program, fertilizer may increase the severityof the damage.• Soil pH should be considered when selecting afertilizer.• The amount of fertilizer applied should be the minimalamount needed to achieve the defined objective.• Read and follow all label instructions and safetyprecautions.• The types and rate of fertilizer should be specified,aswell as the timing, method, and location of application.Slow-release fertilizers are often preferred. Highlevels of nitrogen fertilizer may reduce flowering insome plants.WHEN TO FERTILIZEFertilization MAY be justified in the following situations:• If trees and shrubs are newly planted (thus justifyingfertilization until established);• If homeowners or clients desire more or faster growth;• If landscape beds have been leached of nutrients byflooding or overirrigation;• If trees and shrubs are NOT near fertilized turfgrass;• If established plants are lacking in foliage color ordensity for the homeowners’ or clients’ purposes;• If plants exhibiting nutrient deficiencies are insituations where they cannot be replaced withbetter-adapted species.Fertilization may NOT be required in the followingsituations:• If homeowners or clients are pleased with the appearanceof their landscape plants;• If plants are established;• If plants are flowering or fruiting, since exposure tohigh nitrogen at this stage may impede development;• For tees, unless nutrient deficiencies exist.If landscape plants exhibit nutrient deficiency symptoms,they may not be suited to the site due to soil pH, soildrainage, soil salts, limited soil volume, irrigation waterquality, or mineral content of the soil. Consider replacingsuch plants with others adapted to the site’s conditions.HOW MUCH TO FERTILIZEGeneral RecommendationsWhen it has been determined that fertilization is necessary,most established landscape plants should be fertilizedat rates within the ranges shown in Table 6.Table 6: Landscape plant nitrogen fertilization rates.Level of MaintenanceAmount of Nitrogen Fertilizerpounds N/1000 ft 2 /yearper 3' diameter plant/yr*Oz.**Tablespoons**Basic 0 – 2 0 – 2 0 – 4Moderate 2 – 4 2 – 4 4 – 9High 4 – 6 4 – 6 9 – 13* Typical, assumes 15% N 50% slow release, Approx 7 sq. ft. root zone.** 1 lb. N rate is about 1.5 oz. or 3 Tablespoons per 10 ft 2 per application.34FLORIDA FRIENDLY BEST MANAGEMENT PRACTICES for Protection of Water Resources by the Green Industries