According to a publication released by North Caroline State University, one of the top-ranked landscape architecture schools in the country, the best soil pH for growing vegetables ranges from 6.0 to 6.5, which is slightly acidic. Growing vegetables in alkaline soil (soil with a pH value greater than 7.0) can be a difficult undertaking that needs considerable planning and care. Testing a soil sample every three to four years will indicate the pH value of the soil and which vegetable plants will be best suited for it.
Brassica plants are sometimes referred to as cabbages and include cabbage, broccoli, Brussels sprouts, and cauliflower. Broccoli contains large quantities of vitamin C at 220 per cent of the recommended daily value and high levels of potassium and dietary fibre. Cauliflower, another member of the brassicas, has 100 per cent of the daily value of vitamin C and also has higher levels of potassium than other vegetables. Cabbage contains many B vitamins, potassium, and vitamin A, in addition to protein and vitamin C.
Vitamin A is very important to human vision and helps to maintain healthy teeth, skeletal tissue, and skin. Carrots contain 110 per cent of the recommended daily value of vitamin A and can grow in soil with a pH value as acidic as 5.5 or as alkaline as 7.5, but it does best in ranges from 6.5 to 6.8 in pH.
Vegetables in Slightly Alkaline Soil
Vegetables that grow well in soil with a slightly alkaline pH include beans, cucumbers, pumpkins, zucchini, onions, asparagus, and sweetcorn. Cucumbers have moderate levels of vitamins A and C and make excellent additions to a nice salad. Pumpkins contain large quantities of beta-carotene, which is converted to vitamin A in the body and is an important anti-carcinogen. Onions have healthy amounts of vitamin C and dietary fibre.
Higher Alkaline pH Values
Some vegetables such as yams, okra, mushrooms, and peppers can grow in soils with alkaline pH values as high as 8.0 but prefer more neutral soils. Yams are good sources of vitamin C and dietary fibre, containing 27 per cent and 21 per cent of the recommended daily values respectively. Other than being good sources for potassium, they add a unique flavour to anything from sauces to stir-fry dishes. Ten ounces of okra--a mainstay in many southern kitchens--is loaded with vitamin K (152 per cent of daily value), folate (93 per cent of daily value), and manganese (130 per cent of daily value). It also has 52 per cent of the recommended daily value of vitamin C.