It only takes a German cockroach 4-6 weeks to reproduce and then she produces 30-40 young at a time. Given the right conditions, it just a matter a time before the floor collapses under the sheer weight of their numbers.
They can be more than a match for DIYers
How to Prevent Future Cockroach Infestations
German cockroaches are serious pests that you definitely don’t want to find in your home. It’s essential that you take pest management steps even before you’ve ever seen a cockroach to avoid attracting them and keep them out of your house or apartment.
Developing thorough, regular cleaning habits and rigorously eliminating sources of water is perhaps the best way to keep cockroaches away. Without food and water, they’ll quickly look for the next place that provides them crumbs, leftovers, and moisture.
Make sure you clean up food and wipe counters each night. It’s also important to sweep and vacuum frequently. Even old spills and splatter around your stove can feed and provide a drink to a cockroach, so take an extra minute and wipe these areas carefully.
It’s easy to let dirty dishes stack up in the sink if you don’t have a dishwasher. However, that’s like leaving a buffet with free drinks for pests. Clean dishes at least once per day and keep them organized in your cabinets to reduce potential hiding spots.
Small German roaches can get into a surprising number of pantry items, even if you think they’re closed. Cardboard boxes and plastic bags are often not enough to keep determined roaches out. Instead, store pantry goods, such as cereal, sugar and flour in tightly sealed plastic or glass containers. These precautionary measures can go a long way in deterring hungry roaches.
Your inspection probably revealed at least a few cracks or holes that could let roaches in. You should use caulk to fill these entry points and seal any other cracks or crevices you find. Look for gaps where pipes pass through the wall, focusing especially on the kitchen and bathrooms.