Gordon Johnson, Extension Ag Agent, Kent Co.; gcjohn@udel.edu
Each year there are some lima bean fields that end up with lower stands than expected due to poor field conditions (i.e. crusting after heavy rains, planter malfunctions, seed quality issues, or errors in setting planting rates). Recommendations are for a stand of 3 to 4 plants per foot of row for baby limas. In fields with lower populations, what yield effects can be expected?
The answer is very little, if any, yield losses will occur unless there are large gaps between plants, because lima beans have a great ability to compensate for lower populations by producing larger plants. In a two year study by Dr. Wally Pill at the University of Delaware, ‘Maffei 15’ baby lima bean seeds were sown at the recommended rate and then some plots were thinned within 2 weeks of planting to provide 0%, 16.7%, 33.3%, and 50.0% stand reduction. The research showed that even at 50% stand reduction, overall plant biomass per area was only reduced by 14-21%. The conclusion of this research was that the ‘Maffei 15’ lima bean tolerates a considerable loss of plant stand with little or no effect on yield.
Other research and grower reports support this claim.