alkaline vs. acidic liquids-plant growth?

Question

does anyone know how alkaline liquids and acidic liquids will affect plant growth?

Answer 1

Most plants grow best at a pH of 6.5 as the greatest volume of plant nutrients are available for uptake by the roots at this pH level. This defines the neutral range for soil as 6.5-7. The pH range of most soils is between 5.5 and 7.5.
Acidic soils range form pH 5.0 to 6.0 and extremely acid soils range from pH 4.0-5.0. This definition is based on how the pH effects the nutrient availability.
If you add acid the decrease in pH results in a release of positively charged ions (cations) from the cation exchange surfaces (organic matter and clay minerals). In the short term acidification thus increases the concentration of potassium (K), magnesium (Mg), and calcium (Ca) in soil solution. Once the cation exchange surface has become depleted of these ions, however, the concentration in soil solution will be quite low causing nutrient deficiency symptoms. Acid soils can lead to deficiencies of phosphorus, calcium, magnesium and molybdenum, as well as toxic levels of manganese and aluminium. Alkaline soils may lead to deficiencies in iron, manganese, boron, copper and zinc.
http://www.planetnatural.com/site/xdpy/kb/soil-ph-nutrients.html
http://www.extension.umn.edu/distribution/horticulture/components/1731-03.html
A pH level of around 6.3-6.8 is also the optimum range preferred by most soil bacteria, although fungi, molds, and anaerobic bacteria have a broader tolerance and tend to multiply at lower pH values. If the pH is very low the sour soil will putrefy and smell off. If the soil biota are happy the soil nutrients are readily renewed and soil fertility is maintained producing a pleasant earthy scent.


Please note roses are not considered acid loving plants as they are such heavy feeders acid soil is too limiting in nutrients. Most roses grow with a soil pH range of 5.8 - 7 but a neutral soil pH of 6.5 is ideal. So they handle only the slightest acidity in soils. The acid soil range is form pH 5 - 6 and extremely acid soils range from pH 4 - 5. Plants, such as azaleas, rhododendrons, blueberries, white potatoes and conifer trees tolerate acid soils and grow well at pH 5.0 - 5.5. The majority of food crops prefer a neutral or slightly acidic soil. Some plants however prefer more acidic (e.g., potatoes, strawberries) or alkaline (brassicas) conditions.

Answer 2

Depends on the plant. Some like a slightly acidic soil and others will do better in more alkalai soil. For example, roses and pine trees prefer a more acidic environment. Actual acids or alkalai solutions are probably too strong for most plants to handle if poured directly on them. A pH shift of two or three in either direction is probably OK.