(Phaseolus lunatus) Lima beans are native to Latin America and thrive in super hot locales. Lima beans require 60 to 90 warm, frost-free days in order to mature. Ideal germination temperature is 85F and plants grow best between 70-80F. Plant 1 to 1 ½ inch deep, 6 inches apart. Direct seed outdoors well after the danger of frost has passed; the beans will not tolerate cool soil, so it is best to wait until temperatures are reliably warm before planting. Soaking seed beforehand is not recommended. Vining varieties require the support of a trellis.