Homemade Bug Spray for Plants with Castile Soap
This homemade bug spray for plants takes one tablespoon of Castile Soap and a litre of water. Use it on aphids, whitefly, mealybugs and spider mites on houseplants.
Takes 2 minutes · Makes 1 litre
What you’ll need
- 1 tbsp (15 ml) Organic Castile Soap
- 1 litre rainwater, distilled or boiled and cooled water
- Glass Trigger Spray Bottle
Method
- Mix 1 tbsp Organic Castile Soap into 1 litre of water and pour it into a Glass Trigger Spray Bottle.
- Test it first: spray a few leaves and wait a day to check for brown spots.
- Spray the whole plant, especially the undersides of the leaves and where the stems meet, until the bugs are wet.
- Spray in the morning or evening, out of direct sun.
- Repeat every 4–7 days for 2–3 weeks to catch the bugs that hatch after each spray.
Aphids, whitefly, mealybugs, spider mites and other soft-bodied pests on most houseplants and patio plants.
Soap kills soft-bodied insects on contact: it breaks down their protective outer coating, and they dry out. Once the spray has dried, it stops working, so it doesn’t build up on your plants.
Because it only works when it’s wet, you need to hit the bugs directly. That’s why the undersides of leaves matter, and why you repeat it.
Sensitive plants: Ferns, succulents and plants with furry leaves, like African violets, can scorch. Test a leaf first, or rinse the plant with plain water a few hours after spraying.
Plants in hot sun: Spraying in strong sun can scorch leaves. Spray in the morning or evening.
Essential Oils: Leave them out. Even a few drops can burn leaves.
Mix fresh for each round of spraying. Leftovers keep for about a week.
Keep out of eyes. Safe around pets once dry, but keep them away from plants while you spray.
B&M Pro-Tip 1:
Use rainwater or distilled water. Minerals in hard tap water react with soap and make the spray weaker.
B&M Pro-Tip 2:
Wipe off heavy clusters of bugs with a damp cloth before spraying. Then the spray can reach the ones you missed.
Quick questions
Will it harm my plant?
Most plants are fine. Test a few leaves first and wait a day. Ferns, succulents and furry-leaved plants are the most sensitive.
Can I use it on vegetables and herbs?
Yes. Rinse them well before eating.
Why are the bugs back after a week?
Eggs aren’t affected by soap. Keep spraying every 4–7 days for 2–3 weeks to catch each new hatch.
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