How To Fertilize Muscadine Vines
In general, muscadine vines aren't heavy feeders and don't need much fertilizer after they are well-established. Too much fertilizer can stimulate wood and leaf growth rather than fruit production. Moderate amounts of fertilizer during the first and second years after planting will help stimulate young plants to size up for earlier fruit production.
Feeding At Planting Time
First, a word of caution. Never use manure of any kind at time of planting or around young muscadine plants. Sawdust, cottonseed meal or peat moss may either slow down growth, damage or kill the plants. At time of planting, never put commercial fertilizer in hole around roots. You can thoroughly mix in some bagged top or potting soil at a 25% or so ratio to condition dense clay soil.
Feeding Thereafter
As previously mentioned, muscadine vines are not heavy feeders. These natives are right at home in the soil of southern gardens and can pick up the nutrients they need from the native soil. At the most, and after plants have become established, a light application in spring of a slow-release, non-burning organic plant food can be beneficial during the first few years after planting.
Soil pH is Important!
Muscadine vines grow best in a slightly acid soil ranging between 6.0 to 6.5 on the pH scale. Most average garden soils fall between a pH range of 6.0 to 7.0.
Testing Soil pH
Soil pH is a measurement of the alkalinity or acidity of soil and is measured on a scale of 1-14, with 7 as the neutral mark. Any measurement below 7 indicates acid soil conditions, and anything above 7 indicates alkaline.
If you're unsure about the pH of your soil, or whether or not it is suitable for growing muscadine vines, it's a good idea to test the pH in the planting area. You can quickly test soil pH with an inexpensive soil pH tester probe. To raise the pH (make more alkaline) you can add pelletized limestone to the soil. To lower the pH (make more acid) you can apply Soil Sulfur, Aluminum Sulfate, or Chelated Iron. Adding organic compost to the soil or using compost as mulch can also help to increase acidity and maintain acid soil conditions.
Learn More: What is Soil pH and How To Adjust It?
How To Water Muscadine Vines
When established, muscadine vines are quite drought tolerant. That said, they produce better with a consistently moist soil, especially when there is fruit on the vine.
After Planting
Immediately after planting deep soak the soil in the planting area, including the rootball, to a depth of at least 6 inches or equal to the height of the root ball.
During the First Active Growth Season
In average garden soil you should not have to water your new muscadine vines every day. More often than not, this causes soggy or wet soil conditions that can lead to root rot and other plant diseases. In the absence of sufficient rainfall, water only as needed to keep the rootball and surrounding soil moist. Apply an organic mulch to help retain moisture and reduce handwatering. Keep in mind that deep soaking less frequently is much better than splashing just a little water on the plants every day. Plants planted during the winter dormant season, when plants are not actively growing and evaporation is much slower, will require much less water. So, be careful not to overwater during winter!
Thereafter
When established, muscadine vines are quite drought tolerant and will require less water. That said, I suggest watering enough to keep the soil damp to moist when their is fruit on the vine. A 2-inch layer of natural mulch such as leaves, pine straw or shredded wood mulch can to help retain moisture.