When it comes to growing grape vines and maintaining healthy vineyards most people agree that grapes just aren’t as fussy about their soil as some are fruit species are. Grape vines tolerate a large range of soil conditions and soil chemistry. That doesn’t mean that grapes don’t grow better in certain kinds of soil, though. Even though they will grow just about anywhere, grapes will not thrive in particularly boggy, swampy, or waterlogged environments, extremely acidic, or completely alkaline soil, or those that are barren, or void of nutrients.
What kind of soil do grapes grow best in?
Those experienced with farming grapes recommend a sandy loam as the best soil for growing grapes. The characteristics of sandy loam cater to a grape vine’s needs more than other soil types. The most important factors are that it drains fast, but retains some moisture and has an appropriate amount of nutrients and organic matter. Sandy loam in most cases, also easily maintains the ph range that grapes prefer.
In some cases grapes are also capable of thriving in silty loam. However, in many instances these silty soil types will need a moisture balancing amendment to support the growth of healthy grape vines. Silty soils tend to hold a lot of water, like clay and can easily become too waterlogged to support grapes if left as is.
Check your soil before you plant
The first thing you should do, before planting is to test your soil. Testing your soil can tell you the general pH level, amount of organic material, its physical characteristics and its chemistry. By knowing all of this you will have all of the knowledge you need to ensure your soil is perfect for optimal grape growth.
If it needs amended, you will know exactly what you need to add to perfect it. For example, grapes need a pH level of 5.5 – 7.0 in in order to thrive. Lime can be used to increase the pH of your soil and sulphur can be used to reduce the pH. Many commercial soil testing kits are available and some are more thorough than others. Be sure to choose one that includes pH level and organic material testing at the minimum.
Test Soil Drainage
Grapes don’t like to sit in soggy soil and are prone to root and vine rot in conditions that are too wet. However, they also need a lot of water, grape vines and the grape itself is comprised mostly of water. Due to this, you will need a well draining soil, that can also retain some moisture. Well-drained soil is defined as soil that leaches all standing water within 24 hours.
To test the drainage of your soil, dig a 12×12 inch hole that is 12 – 18 inches deep in your planting area. Fill this hole with water and allow the ground to absorb it for 30 – 60 minutes. Once the hole is empty, or the time is up refill it again and leave it for 24 hours. If the hole has completely drained after 24 hours your soil drains well enough to support healthy grape vine growth.
If the hole has not drained completely in 24 hours, your soil does not drain well enough for grapes. If the hole has completely drained within only a few hours of being filled the second time, your soil is likely too dry to support grape vines. In either of these cases, the soil will need amended with the proper moisture balancing material to correct the problem.
Amending or improving your soil
Most soil types are capable of being amended fairly easily by adding organic matter. Boggy, waterlogged soil types, or especially hard soil types like silt and heavy clay can be amended by adding vegetable composts, manure, pine bark, chopped hardwood and pea gravel. These materials work to aerate and break up the soil density, allowing it to drain better and prevent it from clumping and compacting. Never use sand to amend boggy, clay, or silt based soils. Sand will contribute to the soil density and make the soil harder, more compacted and more prone to flooding.
Soil types composed mostly of sand often benefit from organic compost, peat moss and humus. These materials will make the soil denser and allow it to retain adequate amounts of water, while also providing a sturdier anchor for root growth and helping to prevent excessive erosion.