http://www.tcpalm.com/news/2012/mar/02/start-the-season-with-good-dooryard-citrus-care-20/
Start the season with good dooryard citrus care
Erick Gill
Posted March 2, 2012 at 4:27 p.m., updated March 2, 2012 at 4:27 p.m.
FORT PIERCE Although spring does not officially begin until March 20, a warm winter has dooryard citrus trees showing signs of new growth and bloom. Getting your dooryard citrus off to a good start in the spring is important to realizing a good crop in the fall. Fertilization, pest management and proper irrigation are all necessary to make your trees perform well.
The first new leaves of spring are important because they will provide the photosynthates to feed the flush of new roots that will soon be generated below the soil surface. These new roots are very good at gathering the nutrients in the soil that will nourish the new leaves and fruit for the coming season.
The homeowner should use a citrus mix that will contain additional fertilizer nutrients such as magnesium, manganese, iron and zinc that may not be found in lawn fertilizers. These nutrients, although needed in relatively small amounts, are very important in a number of energy processes within the plant, including pollination, cell formation and photosynthesis. Most fertilizers will have recommendations on the bag, but trees 1-2 years old should be fertilized 4-5 times per year with 1-2 pounds per tree, with the first application being applied in late February. Trees 3-4 years old should receive 3-4 applications per year of 2-4 pounds per tree.
Organic fertilizers may be used, although the nutrients they contain may be more slowly available. The turf from around the trees should be removed and the fertilizer be applied in a circle at the dripline where the fibrous feeder roots are present.
The new leaves that are produced in the spring are magnets for Citrus leafminer and the Asian citrus psyllid. The leafminer larva burrows between the leaf surfaces and disfigures the leaf, lessening its usefulness and also providing an entry point for citrus canker bacteria. Feeding by the Asian citrus psyllid also disfigures the young leaves and transmits citrus greening, a fatal bacterial disease that has infected many dooryard citrus trees. Environmentally friendly horticultural oils such as Organicide, Neem oil or Volck oil may be applied in sprays with water on the young foliage to discourage the adult insects from laying eggs. The first spray should be applied when the new leaves are ½ to 3/4 of an inch long and then sprayed again 7-10 days later.
Micronutrient mixes, usually in a liquid form, can also be added to the spray mixture to promote increased plant health. Always add the oil last to the tank mix and carefully read and follow the instructions on the pesticide or nutritional product label. The horticultural oils and micronutrient mixes are readily available at most garden stores.
The spring period of the year is the most critical for citrus irrigation in order to set a crop and also to produce good fruit size. The long-term forecast is for yet another very dry spring, so supplemental irrigation is probably going to be required on a number of occasions during the coming months. Homeowners will find that applying enough water once per week to the tree to wet the rooting zone to a depth of 12 inches under the tree will be sufficient in all but the driest periods. This will almost certainly require some time invested with a watering hose to add this additional water. More frequent irrigation with lesser amounts of water will result in a tree with a shallow root system that is less able to withstand stressful periods.
Tim Gaver is a Commercial Citrus Extension Agent at the St. Lucie County Extension Office: 772 462-1660. The Extension Office is a Division of the St. Lucie County Environmental Resources Department (ERD). Most dooryard citrus questions are directed to Master Gardener volunteers who can answer most homeowner citrus inquiries.
