How To Fertilize Grapevines

Grapes have been cultivated for so many years now, thousands of years with countless varieties, many types of vines. If soil is moderately fertile, usually grapes require no fertilization, but if your soil is not very fertile there are various types of fertilizers that can be used to fertilize your grapevines. It’s extremely important to have the right amount of fertilizer, as excessive fertilizer will result in rapid growth while decreasing the quality of fruit production. Different nutrients are to be used during different growing seasons.

If you have not yet planted your grapevines, it’s possible to make some adjustments before planting if you wish to plant in the next 6 months or a year.

  • Check soil nutrients and soil pH with at-home testing strips
  • Soil pH of 5.5 to 7.0 is the ideal pH required
  • To raise pH you can add dolomitic limestone to the soil.
  • To lower the soil’s pH you can add sulfur.
  • If your soil pH is fine, but magnesium levels are low, you can add 1 pound of Epsom salts for every 100 sq ft of planting space.

Fertilize Grapevines

Grapevines require Nitrogen, zinc and potassium application for healthy and proper growth of both vine and also to produce top quality fruit.

  • Nitrogen application: during the spring, when grapevines grow rapidly, they require nitrogen. Poultry or rabbit manure are some sources of nitrogen that can be applied, 5 to 10 pounds should ideally be applied per vine. You can also apply 5 to 20 pounds of cow or steer manure per vine. Urea, ammonium sulfate and ammonium nitrate are other fertilizers you can use if you need to increase the content of nitrogen, they have to be applied after bloom. ¼ pound of urea, ⅜ pound of ammonium nitrate and ½ pound of ammonium sulfate can be applied per vine.
  • Zinc application: zinc aids the grapevines in essential plant functions like pollination and hormone production. Shunted shoots and leaves, as well as reduced fruit set are signs of deficiency in zinc. You should apply zinc about a week before the vines are in full bloom. You need to make a zinc spray with a concentration of  0.1 pounds per gallon and apply it to the foliage of each vine. You could also daub fresh pruning cuts with the zinc solution.
  • Potassium application: decreased shoot growth, chlorosis- yellowing of plants and burning during summer are signs of potassium deficiency. You should apply potassium fertilizer during the spring or early summer when the fruits are beginning to be produced. If the tests show a mild deficiency, you may apply 3 pounds per vine, for severe potassium deficiency, you need to apply 6 pounds per vine.

Organic Fertilizers:

Close up image of farm workers putting down fertilizer in a block of table grapes in south africa

Organic nutrient sources are highly diversified and they vary both in quantity as well as quality. They generally come from minerals, plants and animals. Some fertilizers contain huge amounts of only one nutrient and have trace amounts of other nutrients. Some fertilizers release the nutrients slowly, hence higher rates of organic fertilizers are needed to compensate for lower nutrient content. Organic fertilizer is a material with carbon content and one or more other elements except for hydrogen and oxygen essential for plant growth

  • Manure and compost amendments: while compost and manures are considered the essentials of organic fertilizers, amendments can often vary in the amount of nutritive value it provides and thus can be applied also as a basic source of carbon to increase long term soil health and to enhance it as well. The carbon content is often variable, but generally, it ranges, on a dry-weight basis from 20 to 40 percent.
  • Manure: organic farmers have embraced the practice of using livestock manure to build up the health of the soil, specifically the organic matter in the soil. Increasing soil organic matter increases water holding capacity of sandy soils, improves the soil structure, reduces erosion by wind and water, improves drainage in clay soils and promotes the growth of earthworms and other beneficial soil organisms.
  • Compost: adding to nutrients in the soil plus the increase in soil organic matter is the most important benefit of using compost. Generally compost contains low relative concentrations of potassium, phosphorus and nitrogen as compared to manure.

Application of manure and compost: use a broadcast manure spreader to uniformly apply manure or compost on the surface of the entire vineyard prior to planting it or in an existing vineyard, provided the equipment can fit within the rows of the vine.

Inorganic Fertilizer

Care vineyards, grapes

According to their materials, quantities of nutrients and mechanisms of nutrient release, many different types of commercial fertilizers are available for use in vineyards. These commercial fertilizers are broadly classified into:

  • Nitrogen fertilizers: many different forms of nitrogen fertilizers exist, both chemical and physical. Vines can use nitrogen in either ammonium nitrogen form (NH4) or nitrate-nitrogen form (NO3). Nitrification is the process of changing ammonium nitrogen to nitrate nitrogen by bacteria.
  • Phosphorus fertilizers: many different forms of phosphorus fertilizers exist, both chemical and physical. Vines absorb most of their phosphorus from the soil as orthophosphate, regardless of the original source.
  • Potassium fertilizers: potassium can be classified into exchangeable or available potassium, it is absorbed into the soil and released very slowly, the second classification is unavailable forms of potassium ( potassium in soils).
  • Sulfur, magnesium and calcium fertilizers: there are many sources of sulfur, calcium and magnesium fertilizers, The most common sources are materials like bone meal, wood ash, sludge and manures can contain necessary amounts of these elements.
  • Micronutrient fertilizers: many different types of fertilizers are marketing as micronutrients. Usually, they are mixed with fertilizers that contain nitrogen, potassium and/or phosphorus. Micronutrients are needed in very small amounts, the best way to correct inadequate amounts is by foliar feeding.
  • Chelates: synthetic organic compounds are wrapped around a metal ion to neutralize it electrically to increase its availability. This is called the “chelating” of metal micronutrients. Chelates of copper, iron, zinc and manganese have become standards in many vineyards.

Growing Grapes In A Raised Bed

How To Fertilize Grapevines

Growing grapes in a raised bed have many benefits, it will ensure maximum fruit yield and also very healthy plants. Raised beds allow you more control over the conditions of the soil and will also make the harvesting of grapes easier. A miniature vineyard will also make a beautiful landscaping feature.

  • Grow grapes in such locations where there is good air circulation and also receive a minimum of 8 hours of sunlight.
  • To prevent overcrowding, leave a distance of 6 to 10 feet between individual plants at the time of planting.
  • Pull all weeds as soon as you see them sprout.
  • To promote growth give the young vines one-inch water a week.
  • Apply water directly on the roots, do not get a large amount of water on the leaves, as it will make them prone to fungal diseases.
  • Proper application of fertilizer should be done

Readmore: Taking Care Of Grape Plants

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