Contact your local county Extension office through our County Office List.

   
Planttalk Colorado™ is sponsored by Colorado State University Extension, Denver Botanic gardens, and the Green Industries of Colorado. For additional information on gardening, see Plant Select® and Extension Publications.

1338 – Whitish Crust on Potting Mixes   Arrow divider image - marks separation between nested pages that are listed as breadcrumbs.

The white or tan crust on the surface of house plants’ potting mix is a buildup of soluble salts. Excess soluble salts burn foliage, damage roots and lead to problems with water uptake. Wilting, yellowing, and marginal and tip burn of leaves, also called scorching, are symptoms of excess soluble salts.

Soluble salts also accumulate on the outside of clay pots, around drainage holes on pots and even on the stems of plants. Salts come from the potting mix, fertilizers or high salts in the water used to irrigate the plants. These salts rise to the surface of the potting mix by a process called capillary action, especially when the pot sits in a saucer containing excess drainage water. Excess salts cannot drain through the pot when saucers keep water under the container because the water is re-absorbed. Leaching salts from the soil is an easy remedy for plants affected by excess salt.

For additional information, see the Planttalk Colorado™ script:

Tell us what you think!

Do you have a question? Try Ask an Expert!