Commodities: Fieldcrops: Peanuts: 2008 Peanut Update
2008 Peanut Update
Peanut Planting Dates
John P. Beasley, Jr.
Recommended planting date for peanut in Georgia is dictated by tomato spotted wilt virus (TSWV). Prior to TSWV becoming a major yield limiting factor, the recommended time to plant peanuts in Georgia was April 15 to May 20. Soil temperature at the 4-inch depth is a better indicator of when seed should be planted within these dates. It is recommended to plant after the average 4-inch soil temperature has reached 65 degrees Fahrenheit for three consecutive days or longer. Do not plant just ahead of an approaching cold front that would rapidly drop soil temperature. Typically, the 4-inch soil temperature in most soils in peanut producing counties in Georgia is warm enough to proceed with planting within the dates mentioned above. However, in some years it may be cooler than normal in April; therefore delay planting until the soil temperature warms to the recommended level.
To determine the average 4-inch soil temperature, the maximum and minimum 4-inch soil temperature must be known. If the maximum and minimum soil temperatures are not known, then use a soil thermometer and measure the 4-inch soil temperature at mid-day.
Soils with sandier texture tend to warm quicker in early spring than soils with more clay. Sandy soils are more susceptible to rapid cooling and take longer time for soil temperatures to stabilize. Soils with a higher percentage of clay reach a desired average temperature slower but are quicker to stabilize and less susceptible to rapid drops in temperature.
Avoid late plantings if possible. In 2005, an unusually high number of acres in Georgia were planted in June, especially in mid to late June. Many of those fields did not reach optimal maturity when the weather turned cold in late October. In 2007 the drought forced late planting as well. We were fortunate that temperatures in late October and earl November of 2007 were not as cold. That is always a risk with June planted peanuts.
Years of data show no significant yield differences between mid-April and mid-May plantings except where TSWV is high. However, average yield of June planted, non-irrigated peanuts is substantially lower than peanuts planted during the recommended period. Under irrigation, the planting date can be extended into late May or early June without significant reduction in yield; however, quality may be reduced. These late planting dates normally provide adequate heat for maturity but unseasonably cool temperatures can slow the maturation process and delay harvest. Try to avoid planting late maturing varieties after May 20th.
The following three charts show peanut cultivar response to planting dates.
Response of Peanut Cultivars to April and May Planting Dates, UGA Coastal Plain Experiment Station, 2007
Comparison of Planting Dates at Various Locations in Georgia, 2007
Response of Peanut Cultivars to April and May Planting Dates, UGA Coastal Plain Experiment Station, 2006
You can generally spread harvest dates by staggering planting date, provided conditions are favorable for rapid and uniform growth, flowering and pod set. Planting too late may result in loss of yield and quality. Frost damage is also a late planting risk. Planting late also extends the period when peanuts need the most water (during pegging and pod fill) into late August and early September, normally a dry period. Proper planting date is only one phase of peanut production management. Cultivar selection, cultural practices, disease severity, plant population, insect and weed pressure, and environmental factors all affect yield and quality.
For high yield and quality, obtain adequate stands from high germinating and vigorous seed. Avoid replants by timing planting to weather conditions using recommended planting methods and paying attention to seed quality. Poor rotational practices can increase the pressure on seed due to diseases, insects, weeds and other pests.
Peanuts should germinate and emerge within 7 to 10 days after planting. Germination begins when the seed absorbs water. Water intake is uniform around the seed surface and increases as temperature increases. When seed moisture reaches about 35 percent, germination can occur. The time interval for germination and emergence depends not only on seed quality but to a great extent on environmental factors such as temperature and moisture which are influenced by seedbed preparation and planting depth. Dry, cool soils can slow emergence up to three weeks. Seed that has not emerged after three weeks have probably been killed by soil pathogens or will produce weak abnormal seedlings if they germinate. Peanut seed are encased in a thin skin that offers little protection against impact, abrasion, or crushing. Adjust planting units for mild handling of seed.
Follow these practices to develop and maintain a good stand of peanut:
- Find out as much as you can about seed quality. Adjust the seeding rate to the germination of a particular seed lot.
- Plant seed of marginal quality later in the recommended planting period when conditions are more favorable for rapid germination and emergence.
- Follow recommended planting dates and monitor soil conditions.
- Planting depth varies with soil type. Plant seed 2 inches deep on heavier soils. On deep sandy soils, plant 2 2 inches deep. If emergence can be ensured by irrigation, plant about 2 inch shallower than normal. Always irrigate before planting if moisture is limited. As soil becomes dry and soil temperatures increase, plant seed slightly deeper.
- Do not plant immediately before a cool rain because it slows germination and encourages disease.
- If peanuts are planted in a field for the very first time, or if it has been five or more years since a peanut crop was planted to a particular field, then a Rhizobium bacteria inoculant at planting is recommended. Peanut is a legume and requires adequate levels of bacteria to infect roots and produce nodules in which they fix nitrogen for the plant to utilize. Peanut is included in the cowpea cross-inoculation group which consists of many different plants, many of which are native to Georgia.
- Handle seed carefully. Peanut seed is fragile and can easily split or suffer skin slippage if not handled delicately. Do not drop or throw seed bags. Do not leave bags of peanut seed in the hot sun or where they may be damaged by moisture. Keep seed in a cool, dry, well-ventilated area until needed in the field. Poor seed carefully from the bag to the planter to prevent damage to seed.
- Be sure pre-plant incorporated pesticides are properly and uniformly incorporated to lessen any chances of seedling damage.