Hemp responds to a well drained, loam soil with a pH (acidity) above 6.0. Neutral to slightly alkaline (pH 7.0 – 7.5) is preferred. The higher the clay contents of the soil, the lower the yield of fibre or grain produced. Clay soils are easily compacted and hemp is very sensitive to soil compaction. Young plants are very sensitive to wet soils or flooding during the first 3 weeks or until growth reaches the fourth internode (about 30 cm. tall). Water-damaged plants will remain stunted, resulting in a weedy, uneven and poor crop.
Poorly structured, drought-prone sandy soils provide very little natural fertility or support for the plant. Accordingly extra nutrients and water are required to achieve maximum yields on these soils. The cost of irrigation on sandy soils may make production uneconomical.
Used with permission from Hemp.com – Learn about hemp