Peas should be fertilized when planted.
More Info: Peas require a soil pH between 6 and 7 so your initial fertilization will depend on how close your soil pH is to this number.
The soil in which you are planting peas should be mixed with two to three inches of compost followed by an application of fertilizer in the amount of one pound per 100 square feet.
Do not fertilize peas following the initial application upon planting. Supplying peas too much nitrogen will over-stimulate leaf growth which will delay flowering.
How Do You Raise Soil pH?
You can raise the pH of your soil by lowering the acid level with applications of limestone or wood ash. Limestone contains calcium and magnesium, which neutralizes acid in soil. Limestone materials are available in granular, hydrated, pelletized and pulverized forms and should be applied in late winter. Wood ash contains the boron, phosphate and potassium necessary to raise pH levels but takes longer to correct soil conditions than limestone. Wood ash should be applied in fall or winter.
How Do You Lower Soil pH?
In order to lower soil pH, Sulfur and Aluminum Sulfate can be added to boost the acid content. High soil pH occurs when the soil is too alkaline. Plants cannot properly absorb the nutrients they need when the soil PH is too high. The soil needs to be properly PH balanced in order for plants to thrive. An all-natural alternative would be too add pine needles or sawdust to the soil and work it in well to reduce pH levels.