Grapes (muscadine) (Code #128)
Soil Test RatingPotassium

Low K

Coast: 0-70 lbs/A

Pied: 0-120 lbs/A

Medium K

Coast: 71-170 lbs/A

Pied: 121-250 lbs/A

High K

Coast: 171-275 lbs/A

Pied: 251-400 lbs/A

Very High K

Coast: 275+ lbs/A

Pied: 400+ lbs/A

PhosphorusRecommended Pounds N-P205-K20 per Acre

Low P

Coast: 0-30 lbs/A

Pied: 0-20 lbs/A

*-60-60*-60-40*-60-0*-60-0

Medium P

Coast: 31-60 lbs/A

Pied: 21-40 lbs/A

*-40-60*-40-40*-40-0*-40-0

High P

Coast: 61-100 lbs/A

Pied: 41-75 lbs/A

*-0-60*-0-40*-0-0*-0-0

Very High P

Coast: 100+ lbs/A

Pied: 75+ lbs/A

*-0-60*-0-40*-0-0*-0-0

Coast = Coastal Plain    Pied = Piedmont, Mountain, and Limestone Valley

Recommendations:

Recommended pH:5.5 to 6.0. If the pH is less than 5.5, see Lime Table C.
Magnesium:

If soil test Mg level is low and lime is recommended, use dolomitic limestone; if soil test Mg is low and lime is not recommended, apply 25 pounds of Mg/Acre (125 pounds Epsom salts per acre).

Coastal PlainLow: 0 - 60 lbs/acre Medium: 61 - 120 lbs/acre High: >120 lbs/acre
Piedmont Low: 0 - 120 lbs/acre Medium: 121 - 240 lbs/acre High: >240 lbs/acre

Fact Sheet:

*Nitrogen recommendation:

First year vines Apply one ounce of premium grade 10-10-10 fertilizer or its equivalent per vine starting after growth begins in the spring and repeat at four to six week intervals if at least four inches of rain or overhead irrigation have been received since the last fertilization. Apply the fertilizer fairly evenly in a circle 18 inches in diameter with the vine in the center. Reduce the rate or frequency of fertilizations if you see any fertilizer burn. The total number of fertilizer applications for the year will probably be four to five in South Georgia and three to four in North Georgia. Do not fertilize the vines after late August in South Georgia and late July in North Georgia. Slow release nursery fertilizers also give good results with fewer fertilizer applications. Follow the manufacturer's directions on the bag.

Second year vines - Timing and method of applications should be similar to the first year. However, the rate should be increased to four ounces of premium grade 10-10-10 or its equivalent and the diameter of the broadcast circle should be increased to three and one half to four feet.

Third year vines - If the vines have grown off well, apply two pounds of premium grade 10-10-10 fertilizer or its equivalent per vine in March, plus one pound of 10-10-10 fertilizer per vine in May. Evenly spread these applications along the row in a three-foot wide band or apply them in a six-foot diameter circle around each vine.

Mature vineyards - To fertilize an established vineyard, muscadines usually need about 50 pounds of nitrogen per acre applied near bud break followed by about 30 pounds of nitrogen per acre after fruit set. Phosphorus and potassium should be applied according to the soil test. On heavy or rich soils only a single application of nitrogen at bud break may be needed. The desired amount of vegetative growth per year is about three feet. If growth exceeds four feet, reduce the amount of nitrogen applied in future years.

Magnesium deficiency, which shows up later in the season, is of concern to muscadine producers since in severe cases the fruit may shatter prematurely. Symptoms are a yellowing between the veins of older leaves. The yellowing progresses up the shoots as the leaves grow older. If magnesium in the soil is low, follow the recommendation provided. If plant analysis indicates a magnesium deficiency, apply 25 pounds magnesium per acre.

Occasionally, it is necessary to apply boron in some vineyards to realize maximum yields, since boron deficiency can cause poor fruit set. If a boron shortage is confirmed by a leaf analysis test, apply five pounds of borax (10% boron) per acre to the soil surface or spray the vines with one pound of Solubor (20% boron) per acre just before bloom. Do not exceed boron recommendations. Excessive boron will injure or kill the plants.