Spider nests, more accurately called egg sacs, can be removed physically with a vacuum, a glass and piece of cardboard, or a direct spray with an oil-based insecticide. The method you choose depends on whether you’re dealing with a harmless house spider or a potentially dangerous species like a widow or brown recluse. Here’s how to identify what you’re looking at and get rid of it safely.
What a Spider “Nest” Actually Is
Spiders don’t build nests the way birds or wasps do. What most people call a spider nest is an egg sac: a silk-wrapped bundle containing dozens to hundreds of eggs. Some species attach these sacs to webs, others tuck them into crevices, and cellar spiders actually carry their eggs around in their fangs, loosely wrapped in a few strands of silk.
Indoors, you’ll typically find egg sacs in corners, behind furniture, inside closets, in garages, and anywhere that’s dark and undisturbed. Outdoors, they show up under leaves, in tree bark crevices, beneath rocks, attached to plant stems, and within garden webs. A single egg sac can release dozens of tiny spiderlings, so removing them before they hatch makes a real difference.
How to Identify Dangerous Species
Before you touch anything, it’s worth knowing whether you’re dealing with a medically significant spider. Most egg sacs in homes belong to harmless species like cellar spiders or cobweb spiders, but a few deserve extra caution.
Brown widow egg sacs are the easiest to identify. They look like small spiky balls, sometimes described as resembling a World War II naval mine or a large pollen grain. The surface has multiple silk spikes projecting outward, and the sacs are usually suspended in a web near the mother spider, often with more than one sac present.
Black widow egg sacs are smooth, round, and cream to tan in color. They lack the spiky projections of brown widow sacs. You’ll find them in dark, sheltered spots like garages, woodpiles, and outdoor sheds.
Brown recluse egg sacs look like raised white pillows nestled inside a fuzzy, wool-like silk retreat. The mother spider sits right next to the sac. One useful identification trick: brown recluse silk glows brightly under a black light, which can help you spot retreats in dark corners of basements or closets.
If you identify a widow or recluse egg sac, wear gloves and long sleeves before attempting removal. The mother is usually nearby and may be defensive.
Physical Removal Methods
For most egg sacs, physical removal is the fastest and most effective approach. A vacuum cleaner is the simplest tool. Use the hose attachment or an extension tube, approach the sac quickly from underneath, and vacuum up the entire sac along with any webbing and the adult spider if she’s present. The suction damages most spiders and spiderlings on contact, and the tangle of debris inside the canister or bag prevents survivors from escaping. Empty the vacuum bag or canister into a sealed trash bag afterward.
If you’d rather not kill the spiders, you can use the glass-and-cardboard method. Place a drinking glass or bowl over the egg sac, slide a stiff piece of paper or cardboard underneath to seal it, and carry the whole thing outside. Set it in a sheltered spot away from your house, like under a bush or an overturned flowerpot. This works well for a single sac but gets impractical when you’re dealing with multiple sacs or large webs.
For cellar spiders (the long-legged, translucent spiders common in basements), act fast. These spiders vibrate rapidly when threatened, then drop to the ground and run. Circle them with the vacuum nozzle from below to capture both the spider and her egg bundle before she bolts.
When to Use Insecticide
Standard water-based bug sprays are largely ineffective against egg sacs. Research from the University of California, Riverside found that spider egg sacs are constructed with highly water-repellent silk, so water-based pesticide sprays can’t penetrate the outer layer to reach the eggs inside. The eggs survive, and spiderlings emerge normally.
Oil-based aerosol insecticides are a different story. The same research showed that oil-based formulations penetrate the silk barrier effectively, completely preventing spider emergence. If you’re spraying rather than physically removing, look for aerosol insecticides with an oil base, typically sold as “crawling insect” or “spider” sprays in pressurized cans. Spray directly onto the egg sac and into any surrounding crevices or holes where additional sacs might be hidden.
This distinction matters most for outdoor egg sacs in hard-to-reach spots, like up under eaves or deep inside gaps in siding, where physical removal isn’t practical.
Clearing the Surrounding Area
Removing the egg sac alone isn’t enough if the conditions that attracted the spider remain. Clear away any webbing in the area using a broom, duster, or vacuum. Spiders are creatures of habit, and a remaining web signals “good spot” to other spiders looking for a home.
Reduce clutter in garages, basements, and closets. Spiders thrive in undisturbed piles of boxes, old clothes, and stored equipment. Items you rarely use, like gardening gloves, baseball mitts, roller skates, or seasonal clothing, should go into zip-closure plastic bags. This eliminates hiding spots and prevents spiders from crawling into holes where your fingers go.
Preventing New Egg Sacs
Spiders enter homes through surprisingly small openings. Seal cracks and gaps around doors, windows, and foundations with caulk or weatherstripping. Pay attention to where utility pipes and wires enter the house, as these are common entry points.
Outside, trim vegetation so it doesn’t touch your home’s exterior. Bushes, tree branches, and ivy growing against the foundation create a direct bridge for spiders to reach walls, eaves, and eventually interior spaces. Keep firewood stacked away from the house and off the ground.
Reducing outdoor lighting near doorways also helps indirectly. Lights attract the insects that spiders feed on. Switching to yellow or sodium vapor bulbs, which attract fewer insects, makes the area around your home less appealing as a hunting ground. Fewer prey insects means fewer spiders setting up shop and fewer egg sacs to deal with later.