How to raise ph in soil?
Raising soil pH can be critical for your garden plants to thrive.
With the help of soil testing equipment, like soil ph meter for example or professional soil ph tester, you can regulate the actual pH range accurately. But without any scientific background you can correctly apply lime and fertilizer on acid soils.
Unless growing acid loving plants, you should be aiming for a soil reaction somewhere between 6.0 and 6.9. Normally a pH of 7.3 is as high as your garden soil should be allowed to go if growing the usual collection of annuals, perennials, vegetables and shrubs. Though for a lot of plants, even this can be a little high for best results.
Making precise recommendations for how much material is needed for raising soil pH is not easy. Lighter soils require less, heavy soils need more alkalizing agents. The amount of organic matter in the soil changes the requirements. If the organic matter has reduced to humus, this normally increases the amount of chemical needed.
The best way around this dizzying problem is to go ahead and treat the soil to your best estimate, rechecking pH after a couple of weeks, then a month later, and again two months after. If you didn’t apply enough, just add some more. If you applied too much, you won’t do any harm in using sulfur to reverse your efforts to raise the soil pH.
Raise Soil Ph with Lime.
You can raise soil pH by applying lime. Here are some suggested amounts:
To raise soil pH of light sandy loams one full point (i.e. from 5.5 to 6.5) add 35 pounds of ground lime to 1,000 square feet. On a medium loam soil, apply 50 pounds, and on a heavy clay loam, 70 pounds. (Either agricultural lime or the fine chips used for top-dressing driveways can be used.)
Within the 6.0 to 6.9 pH range, all foods needed by the majority of shrubs, annuals, perennials and other “average” garden plants are available in the soil in soluble form, provided the foods are present in the first place. Bacteria thrive and do their vital work better in this pH range, and certain potential poisons, such as aluminum, are locked up so they cannot injure plant roots.
Pay particular attention to the above phrase, “provided the foods are present in the first place.” No matter how much you raise soil pH, it cannot make available any food element that is not present. For example, plants may show by certain signs that they are not taking up iron from the soil. If the pH is high, we might suspect that iron is present but locked up in insoluble form. If, however, plants still show a deficiency of iron after sulfur has been applied to lower the pH, then we know that iron is lacking and must be supplied in a form plants can absorb.
Because plants tend to remove calcium from the soil as they grow, which in turn lowers pH, lime is closely tied in with our use of the pH theory. To a considerable degree, proper lime application to raise soil ph (assuming supplies of plant nutrients are ample) becomes the key to our success with garden soils. This does not mean that the indiscriminate use of lime year after year is the right way to run a garden. Too much alkalinity can do as much harm as too little. This is why no “rule of thumb” can be set up that will work all the time in every garden. The only safe guide is an actual test of soil reaction.
Also you can read the article How to lower ph in soil.
This article was written by Robert C. Harris.