The Q&A Archives: Problems with salty soil

Question: We have a hard clay soil that's very salty. We've put topsoil over it and planted in raised beds, but the salt still rises up through it. We applied sulfur, which lowered the pH to 6.5, but the salt buildup still stunts our plants. What should we do? Johnie Williams Canon City, CO

Answer: Leach it, says James Ells, vegetable crop specialist at Colorado State University in Fort Collins. Flooding the soil with water dissolves built up salts. First you need to take a soil sample to determine your salt reading, explains Ells. If the reading is between four and six milliohms, then leach the soil, irrigating it with six inches of water. If It's between six and 15 milliohms, leach the soil with 12 inches of water. A reading higher than 15 milliohms means you need a drainage system or you should move your garden to a better location. Leaching the soil once should be enough. Use a rain gauge to measure the amount of water you're adding. Be sure irrigation sprinklers are set on low so the water soaks into the soil and doesn't run off the surface, cautions Ells. Lowering the pH by adding sulfur may actually contribute to the salt buildup because sulfur breaks down to calcium salts in the soil. You shouldn't have to add sulfur to Coloradan soils because most have sufficient amounts occurring naturally, adds Ells. If leaching doesn't work, try creating a plastic barrier under the raised beds with a drainage system. Dig a two foot deep trench under the bed, place heavy gauge plastic in the bottom and cover it with a few inches of gravel. Place a drainage pipe over the gravel and fill the trench with enough gravel to cover the pipe, then refill the hole with soil. You may have to line the sides of the trench with plastic to prevent salts from leaching laterally into the bed.

« Click to go to the homepage

» Ask a question of your own

Q&A Library Searching Tips

  • When singular and plural spellings differ, as in peony and peonies, try both.
  • Search terms are not case sensitive.

Today's site banner is by Marilyn and is called "Southern Comfort"