The pH scale indicates acidity or alkalinity. A soil with a pH number below 7 is acid, while one with a pH above 7 is alkaline. Garden plants typically grow best in neutral or slightly acid soil (pH 7 or slightly below; see illustration at left).f your soil is extremely acidic or alkaline and you need to change the level by more than one point on the pH scale, it's best to bring in a professional: he or she can both analyze test results and perform an on-site evaluation to determine whether the soil can be amended successfully and how best to go about it.
There are two different types of vitamin A. The first type, preformed vitamin A, is found in meat, poultry, fish, and dairy products. The second type, provitamin A, is found in fruits, vegetables, and other plant-based products. The most common type of provitamin A in foods and dietary supplements is beta-carotene.
1 Vitamin A obtained from colorful fruits and vegetables is in the form of provitamin A carotenoids, which are converted to retinol by the body after the food is ingested. 2  Good food sources of provitamin A carotenoids include carrots, sweet potatoes, spinach, kale and cantaloupes.