Managing Salt Buildup (white crusty substance) on Houseplant Soil
Improve the health of your houseplants and the look of your indoor garden with a little container clean up.
Scrape off any white crusty substance collecting on the lip of the container or soil surface. This build up of salt from minerals in fertilizer and hard or softened water can damage plants. High levels of these excess salts can prevent plants from absorbing the water they need, stunt growth and burn root tips, leading to rot.
Repeatedly and thoroughly water, called leaching, to wash any remaining salts out of the soil. Water the plant thoroughly until the excess water drains out the bottom of the pot. Use twice as much water as the container will hold. For example a 6 inch pot holds 10 cups of water, so use 20 cups to wash out the salts. Wait 30 to 60 minutes and repeat.
Repeat every six months or so to prevent plant damage.
A bit more information: Reduce the risk of salt build up by always watering thoroughly and pouring off excess water. Fertilize only when your plants are actively growing. And use a dilute solution, about one fourth to one half the recommended rate, when fertilizing.