How to Kill Stubborn Broad Mites

Scrutinize your plants carefully every day. Look for leaves that are beginning to curl either upward or downward. Check for any unusual discoloration. Feel the plant’s foliage. Affected leaves may feel stiff and become brittle. Flowering can be reduced and blooms may be deformed.

Pick off damaged foliage. Seal the infested material tightly in a plastic bag, and dispose of it in the trash. Don’t add it to your compost heap, where broad mites can continue to feed and multiply.

Stuff some rags tightly into the top of the plant’s pot to keep the soil in place. Fill the bathtub with very warm water, between 110 and 112 degrees Fahrenheit. Broad mites are highly sensitive to heat, and water at this temperature is hot enough to kill them without injuring your plant.

Immerse the plant -- pot and all -- completely in the water for 30 minutes. Monitor the temperature constantly with a thermometer. Drain off some of the tub water when it cools and threatens to drop below 110 F. Replenish as needed with warm water to maintain the temperature.

Remove the plant from the water, and take the rags out of the pot. Allow the plant to drain for 30 or 40 minutes.

Add 2 teaspoons of unscented liquid Castile soap to 1 quart of water to make insecticidal soap. Castile is biodegradable soap gentle enough to use on plants. Mix thoroughly. Funnel the solution into a plastic spray bottle.

Spritz the plant generously with the insecticidal soap to the point of runoff. Coat all surfaces of the plant thoroughly, including the undersides of all the leaves. Pay particular attention to new growing tips

Allow the solution to dry completely. Rinse the soap off the plant to avoid risk of damage. Repeat once or twice weekly to kill any new broad mites that might arrive.