How to Leach Soil

Scrape off and carefully remove the white crust that may have formed on top of the potting soil before leaching the soil from a house plant. According to Colorado State University, you can typically remove 1/2 to 2 inches of soil without harming the plant. Be careful of the roots, though. Replace the soil with new potting soil after leaching.

Remove the saucer from the pot, if applicable. Scrape and remove any salts that formed on outside of the pot and on the saucer. Examine the drainage holes; they may be clogged with salts. Remove the salts from there as well.

Water the houseplant with lukewarm water, using two times as much water as the pot's volume. For example, if a 6-inch planting pot holds 10 cups of soil, use 20 cups of water. Pour slowly, allowing most of the water to drain out before putting the saucer back on.

Leach the soil outdoors using a sprinkler. In general, to reduce the salt content by 50 percent in soil with good drainage, irrigate the soil with 6 inches of water. To get rid of 80 percent of the salts, use 12 inches of water. Set a bucket nearby, where it will collect sprinkler water, then measure the bucket's water level to determine approximately how much water you've applied to the soil.