From the Vine – Fertilization

— Written By and last updated by Patricia Burch

March is a time for many plants to break dormancy and begin growth for the new year. Buds are swelling, flowers are blooming, leaves are sprouting, and sap is rising. Another important part of plants is growing which you don’t see, the roots. Roots of many plants grow during cool weather even when the foliage appears dormant. The roots spread to seek nutrient and water reserves that are not yet tapped. Woody plants can absorb nutrients as long as the soil temperature is above 40°F. A quick check of the local weather station indicates that the average soil temperature for this month is 49°F, so the soil temperature is within the optimal range. With the onset of new growth, and with roots growing during this cool weather, plants are depleting energy that was stored from last season and could use a boost from a fertilizer application.

Grapes are one of these plants. For mature vines, broadcast 2 to 3 pounds of 6-6-18 fertilizer under the vine in early to mid-March. In May, broadcast ½ pound of 15.5-0-0 fertilizer under the vine. A third application should be made in June, broadcasting 2 to 3 pounds of 6-6-18 fertilizer under the vine. Grapes also have a high magnesium requirement, which may be lacking in our eastern NC soils. To correct this deficiency, mix 1 tablespoon of Epsom salts in 1 gallon of water and apply 1 cup of this solution per vine.

Pecans are another plant that needs fertilizing in March. For young, non-bearing trees, apply 1 pound of 10-10-10 per year of tree age, up to 25 pounds. Do not exceed 25 pounds of fertilizer per tree on non-bearing trees. For mature, bearing trees, apply 4 pounds of 10-10-10 per inch of trunk diameter measured just below the first branches. When applying fertilizer to pecan trees, broadcast the fertilizer from the drip line to the trunk of the tree. Never dig a hole and place fertilizer in the hole when fertilizing a pecan tree. Research indicates that broadcast applications of fertilizer is sufficient for mature trees since most of the feeder roots are in the top 1 foot of soil.

Ornamental trees and shrubs can be fertilized in March. Broadcast 2 to 4 pounds of a complete fertilizer (10-10-10) per 1,000 square feet of landscaped area. Be sure to spread the fertilizer evenly over the entire root zone, which extends 2 to 3 times the span of the plant. Keep fertilizer off the stems of shrubs and at least 1 foot away from tree trunks. Apply fertilizers when the foliage is dry to avoid fertilizer sticking to plant leaves and causing fertilizer burns. If you do happen to get fertilizer in the foliage of plants, use a broom to shake the fertilizer off the plants and onto the ground.

DO NOT fertilize warm-season lawns now. Warm season lawns with grass species such as Centipede, Bermuda, St. Augustine, or Zoysiagrass should not be fertilized until green-up or later. Fertilizing these grass species now, only feeds the weeds that are actively growing or leaches away into ground or surface waters before the grass can uptake the nutrients.

For more information on fertilizing trees and shrubs, see the “A Gardener’s Guide to Fertilizing Trees and Shrubs” publication from NC State University.

Don’t forget about the Friends of Horticulture classes offered by the N.C. Cooperative Extension of Sampson County. We meet on the third Thursday night of the month and discuss different horticulture related topics.

For all your home and gardening questions contact the Extension Master Gardener℠ program of Sampson County phone clinic at (910) 592-7161.