A commonly asked question by farmers around May to July is "Why my grapevine stopped growing". Similar questions but at different times of the year also are raised like why the grape vine is not growing or how to make the grapevines grow faster. Assuming that your grapevine is healthy otherwise (disease-free), there are few things to take care of to solve the stunt growth and make your vine look great again. We will address the grapevine diseases in another post.
1- Check the PH of the soil: Grapevines like a slightly acidic soil with a pH 6.0-6.5 being ideal but it can tolerate a pH of 5.5-7.0. You can use this soil test kit to determine the next step: If the Soil pH is above 6: use ground sulfur to lower the pH level. If the Soil pH below 5: use ground limestone to raise the pH level.
2- Loosen the bed soil: The grape vine roots prefer loose well-drained soil. Usually this issue will appear at the age of 1-2 years of the plant when the roots start to establish its average territory. Using a manure fork dig around 1 -2 feet vertically and horizontally around the main trunk, but main sure you don't hurt the main root bulb which is usually 8-12 inches around the main truck at this age. Mix the loosen soil area with garden soil especially if you have the sandy type of soil in your garden.
3- Fertilizer or compost soil application: Grapevines like compost which is usually applied every year (at least the first 4 years) around the trunk early in the spring. Otherwise, the grapevines prefer a 10-10-10 fertilizer to be applied just before the bud break in February. Avoid manure with high nitrogen content.
4- Minerals deficiency especially Zinc and Potassium can lead to stunt growth of leaves and shoots as will as chlorosis. These you can apply as directed by the manufacturer late summer or early winter after you prune the vies.
5- How much water grapevines need will vary depending on the age. Watering of grapevines is necessary at least weekly in the absence of rainfall. According to OSU Extension, you should wet down to 6 inches for newly established vines and around 12 inches for older ones only to avoid root rot.
6- For Hot Zones you might consider this mesh plant cover to avoid the sun damage to your vine in the extreme hot summer like in the desert.