This turmeric patch is doing the best of all my turmeric gardens. The spot has had very fresh additions of manure/compost, is kept constantly mulched with grass clippings that are refreshed monthly, gets dappled sun with late afternoon shade. The ground stays moist. This year we've had almost daily light rain, which might have helped.
The patch is 324 square feet. The soil depth is no more than 6 inches, less in a few spots. Inspite of the shallow soil, the turmeric is thriving. That black vertical stick in the photo is a hoe handle that's 4 1/2 foot long. That's gives you an idea of how tall the plants are......mostly 3 1/3 to 4 foot tall.