PH- is measured on a scale of 1-14 with 7 being "neutral". Acids are lower than 7 and alkalis (bases) are above 7. To be technical, the term pH refers to the potential hydrogen-hydroxyl ion content of a solution. Solutions ionize into positive and negative ions. If the solution has more hydrogen (positive) ions than hydroxyl (negative) ions then it is an acid (1-6.9 on the pH scale). Conversely if the solution has more hydroxyl ions than hydrogen it is alkaline (or base), with a range of 7.1-14 on the pH scale.
Pure water has a balance of hydrogen (H+) and hydroxyl (OH-) ions and is therefore pH neutral (pH 7). When the water is less than pure it can have a pH either higher or lower than 7.
When the pH is not at the proper level plants will lose it's ability to absorb some of the essential elements required for healthy growth. For all plants there is a particular pH level that will produce optimum results. Most plants can still survive in an environment with a pH of 5.0 to 7.5.
If the pH is too high, some plants suffer from a lack of iron, zinc, manganese, copper and boron. If the pH is too low, it lacks phosphoric acid, calcium, and magnesium. At lower pH (more acidic) ranges, diseases can thrive. Normally, plants tend to take up more acidic elements, causing pH levels to increase or drift up the scale.
Magnesium deficiency in soil
To get an accurate reading of any deficiency, the soil can be tested, but in the case of magnesium, the results are quite variable. Magnesium content can deteriorate quickly, especially during rain or watering. Magnesium is quite water-soluble and gets leached to the lower layers of the soil easily. It is brought back up by tree roots. It is therefore important to return the falling leaves to the topsoil.
Unless you live in an area where the dolomitic rocks is dissolve in the water, you can be pretty sure that magnesium would benefit your garden, especially if you are not adding tree leaves. Magnesium shortage is a real problem in most parts of the world. It is caused when we water or irrigate instead of growing what is natural for the climatic conditions. It causes a serious calcium metabolism problem in people and animals, because calcium cannot be used without magnesium.
Extreme magnesium deficiency is recognized by pale green leaves and by blossom and fruit rot, but don't wait for that. Sprinkle dolomite or epsom salt on the soil from time to time, or add a little epsom salt to the water. Using a little frequently is better than using a lot once, because the excess just gets leached.
Epsom salt recipe: Dissolve 2 tablespoons of Epsom salt in 1 gal. of water. For healthy nightshade plants (tomatoes, peppers, eggplants) water just as flowering starts. Or use this mixture as a foliage spray in the garden and on house plants.
What dose Epsom Salts do for Plants?
Epsom salts contain hydrated magnesium sulfate, two elements vital to plant growth.
• Sulfur is crucial to the inner workings of plants, but it is almost never lacking in the soil, thanks in part to synthetic fertilizers and acid rain.
• Magnesium (10%) can become scarce in soil, because of erosion or depletion of the top soil or a pH imbalance. Some plants, like lettuce and spinach, don’t mind going without magnesium. Others may exhibit symptoms like leaf curing, stunted growth, which can be attributed to more than one cause.
• In general, magnesium plays a role in strengthening the plant cell walls, allowing the plant to take in the nutrients it needs. It also aids in seed germination, photosynthesis and in the formation of fruits and seeds.
Magnesium sulfate is great for palm trees.