Deciding whether to replant peanuts is a tricky economic decision for growers. Weather conditions and seed quality, storage, and handling all affect peanut germination. Seedlings exposed to wet and cool soil conditions have slower germination rates and are at risk of seedling diseases. Dry soil conditions are also problematic for germination. It is ideal to plant into soils with adequate moisture and temperatures above 68 °F. This year, the southeast region experienced a cold front in early May that negatively affected peanut germination, leading some growers to consider replanting their fields.
Complete replant or supplemental replant?
Research has not found any benefit from a complete replant involving the burn down of the initial planting with herbicide and starting over with a new stand. Instead, use the planter to provide a reduced rate (around 3 seed per ft) of seed 3-4 inches to the side of the row of the initial planting. Providing supplemental seed costs less and utilizes the viable seed already in the ground compared to a complete replant.
When growers provide supplemental seed to poor stands their field will contain plants that vary in maturity. Maturity of plants from both the initial and supplemental plantings will need to be considered when determining optimal harvest time. Waiting later to harvest improves peanut yields by giving replanted peanuts time to mature. It is also important to evaluate podblasting methods of determining maturity, vine conditions of the crop, and weather/field conditions to determine when to harvest.
At what stand count is it economically acceptable to replant?
For single rows, replant by supplemental seed is economically acceptable when stand counts are less than 2.5 plants per foot.
For twin rows, replant by supplemental seed is economically acceptable when stand counts are less than 3 plants per foot.
Provide adequate time to assess emergence!
Growers should replant peanuts as early as possible if needed! However, there can be variability in germination rates especially if seedlings are exposed to cool conditions. To fully consider peanut germination, check stand counts between 2 and 3 weeks after the initial planting and replant as soon as possible. If you plant supplemental seed 4 weeks or later after the initial planting it may be too late. The initial plants can dwarf the growth of the replanted plants.