Southern peas are also known as cowpeas and come from the plant species Vigna unguiculata. Southern peas include field peas, black-eyed peas and other types, with a range of individual varieties. Because southern peas are legumes and not real pea species, they require different cultural care, including fertilization. Depending on the cultivated variety or cultivar, southern peas are typically ready for harvest in 65 to 125 days after planting the seeds.
Older varieties of southern peas grow in more of a vine form, while newer cultivars are bush types. The basic categories of southern pea cultivars are field peas that are vine-like and produce smaller peas, crowder peas that have starchy peas crowded in the pods, cream peas that are smaller plants with light-colored peas, and black-eyed peas. The most popular bush-type cultivars include Mississippi Silver, Mississippi Purple, Mississippi Cream, Clemson Purple and Texas Cream. Semi-vining and vine-type cultivars of southern peas include Colossus, Pinkeye, Dixielee, Princess Anne and Queen Anne.
Apply 2 to 3 lbs. of 5-10-10 NPK fertilizer per 100 feet of row, approximately one week to 10 days before planting your southern peas. A fertilizer application of 3 lbs. of a 10-10-10 NPK formula per 100 feet of row is sometimes used as well. Alternatively, you can spread the fertilizer after planting the peas, forming a band that's 2 to 3 inches away from the pea seeds and 3 to 4 inches deep along the rows. Because southern peas derive nitrogen from the air, avoid over-fertilizing the plants. Applying excessive fertilizer can provide too much nitrogen to the southern peas, causing unnecessary vine growth with poor pea production.
A soil test is the best way to determine the fertilization needs for your southern peas. If you have poor-draining or nutrient-poor soil, keep in mind that you may need to amend the soil before planting the southern peas. Amending the soil with well-rotted manure or organic compost can help. A soil test can tell you the exact amounts of nutrients needed and soil pH. Also, if you've never grown southern peas before at the selected planting site, you might need to inoculate your soil before planting with the Rhizobium bacterium strain for southern peas. Consult your local agricultural extension service for soil testing and inoculation.
Choose a planting site for your southern peas that has full sunlight exposure, medium-fertility soil and soil with a pH of 5.8 to 6.5. The soil should be very well-draining. Because southern peas are warm-season crops, plant the seeds only after the top 4 inches of soil warms up to at least 60 degrees F in spring. For bush types of southern peas, plant the seeds 3/4 to 1 1/2 inches deep with four to six seeds per 1 foot of row. Space the rows 20 to 42 inches apart. For vining types of southern peas, plant just one or two seeds per 1 foot of row.
Aside from fertilization, southern peas require proper watering and weed control. Irrigation is usually necessary only when your area experiences prolonged dry spells or droughts. Watering during dry spells is especially important while your southern pea plants are flowering and filling the pods. Weed control is necessary only when the southern peas are in the seedling stage, because the plants tend to naturally choke out weeds as they grow larger. Weed around southern pea seedlings by hoeing shallowly or hand-pulling the weeds.