how-to
How to Get Rid of Dock Spiders: A Step-by-Step Guide
Table of Contents
- Why Dock Spiders Keep Coming Back
- Step-by-Step Plan to Get Rid of Dock Spiders
- How to Prevent Spiders on Boat Docks Long-Term
- Frequently Asked Questions
Last Updated: September 9, 2026
Why Dock Spiders Keep Coming Back
Dock spiders persist around lake properties because docks provide shade, moisture, and insects. Spraying once treats the symptom, not the habitat, so they return.
The real harbor is underneath: dock frames, floats, and crevices stay damp and dark, where dock spiders lay egg sacs and hide. Address the underside or you will keep battling the same infestation.
Dock spider activity peaks in late summer (extension.umn.edu). Treating in early spring, before egg sacs hatch, is far more effective than reacting in August.
Step-by-Step Plan to Get Rid of Dock Spiders
Start with mechanical removal: use a stiff broom to sweep away cobwebs, egg sacs, and debris from the underside, frames, and pilings, since surface treatments cannot penetrate webbing.
Once clean, apply a targeted treatment in this order:
- Sweep all surfaces including the underside, dock frames, and structural crevices to remove webs and egg sacs.
- Wash down the dock with a hose to remove residual dust and expose remaining spiders.
- Apply a liquid repellent to the underside, legs, and joints of the dock, focusing on shaded areas.
- Treat the perimeter of the dock where it meets the waterline, since spiders often enter from the shore or nearby vegetation.
- Reapply after heavy rain or every few weeks during peak spider activity.
Many owners prefer natural deterrents near water. Mix a few drops of peppermint or citrus oil with water and dish soap in a spray bottle, then mist treated areas; these are water-safe and biodegradable.
For heavy infestations, a professional residual barrier reaches deeper into crevices. Consistency matters: one application rarely solves the problem.
How to Prevent Spiders on Boat Docks Long-Term
Long-term prevention means making the structure less hospitable through regular cleaning and structural modifications.
Sweep the underside and remove egg sacs at the start of the season and again in late summer, before they hatch.
Install a dock cover or skirt, seal gaps between frames and decking, and trim overhanging vegetation that acts as bridges for spider activity.
Many owners choose a professional plan: a licensed technician assesses your dock, applies water-safe treatments, and returns on a schedule aligned with the spider life cycle.
| Prevention Method | How It Works | Best Time to Apply |
|---|---|---|
| Stiff broom sweeping | Removes webs, egg sacs, and debris | Start of season and late summer |
| Peppermint or citrus oil spray | Acts as a natural deterrent spiders avoid | Every 2-3 weeks and after rain |
| Dock cover or skirt | Blocks shaded underside habitat | Permanent installation |
| Professional treatment plan | Reaches deep crevices with residual barrier | Seasonal, timed to egg sac hatching |
Natural ingredients are safe but break down quickly; professional treatments last longer but need care. Many owners combine natural deterrents for routine maintenance with a professional residual treatment for initial knockdown.
Dock spiders persist because docks are ideal habitat. The solution combines mechanical removal, targeted treatment of the underside, and preventative maintenance. At Smokaboji Pest Control, we serve lake property owners across Northwest Iowa and Southwest Minnesota with customized, water-safe treatment plans. Get started with Smokaboji Pest Control and keep your dock spider-free all season.
Frequently Asked Questions
What is the best spider repellent for outdoor docks?
The best spider repellent for outdoor docks combines a water-safe, biodegradable misting concentrate with natural ingredients like peppermint or citrus oil. These deter dock spiders without harming the marine environment. Apply it to dock frames, structural crevices, and the underside of the dock where spiders hide. For heavy infestations, a professional pest control service can apply a longer-lasting treatment that is safe for use near water.
How often should I treat my dock for spiders?
Treat your dock every 2 to 4 weeks during peak spider activity, which runs from late spring through early fall. Regular cleaning and sweeping of cobwebs and egg sacs should happen weekly. Reapply your chosen repellent after heavy rain or if you notice new web activity. Consistent preventative maintenance is the most effective way to keep dock spiders from establishing a large population on your boat dock.
Are dock spiders dangerous to humans?
Dock spiders are not aggressive toward humans, and their bite is not considered medically significant. They prefer to flee rather than confront people. The main concern is the large webs and general pest presence they create around your dock. However, an infestation can be unsettling, especially for children. Removing them is primarily for comfort and cleanliness rather than safety.