266 temperate-zone varieties found no consistent differences. But that is misleading; this species encompasses huge genetic diversity that not even okra specialists have ever seen—it just hasn’t been distributed in the temperate zones.
Okra is a warm-season annual well-adapted to many soils and climates.
Rainfall The plant tolerates a wide variation in rainfall.
Altitude Most selections are adapted to the lowland humid tropics, ranging up to at least 1,000m.
Low Temperature Minimum soil temperature for germination is 16°C. For good growth, night temperatures should not fall below 13°C.
High Temperature An average temperature of 20-30°C is appropriate for growth, flowering, and pod development. Most cultivars are adapted to consistently high temperatures.
Soil A range of soil types give good economic yields but (not unexpectedly) well-drained, fertile substrates with adequate organic material and reserves of the major elements are ideal. Some cultivars are sensitive to excessive soil moisture, so well-drained, sandy locations are preferred. Neutral to slightly alkaline conditions, pH 6.5-7.5, seem best.
The genus Abelmoschus includes from 6 to 15 species in the Afro-Asian tropics and North Australia. One that stands out is abelmosk or ambrette (Abelmoschus moschatus Medik.; syn. Hibiscus abelmoschus). Indigenous to India and cultivated (or weedy) in most warm regions of the globe, it is a low, slightly woody plant with a conical five-ridged pod containing numerous brown kidney-shaped seeds that are smaller than okra’s. The seeds possess a musky odor and perfumers know them as ambrette (“abelmoschus” is from the Arabic “father of musk”, with “moschatus” also referring to a musky smell). The plant also yields an excellent fiber and, rich in mucilage, is employed in upper India for clarifying sugar. One variety there known as bendi-kai is eaten fresh, prepared like asparagus, or pickled. The foliage and tubers of A.m. subsp. tuberosus have been consumed for centuries in Australia.