Subject to Flooding
Before you decide to use the crawl space beneath your home, check to ensure it is not subject to flooding during the wet months of the year. Look for clear indications of water runoff or eroded areas beneath the home. The dirt should have clear paths that the water has traveled over and may even have some damp spots. Avoid using the areas that may get wet during the rainy season or during any kind of rain to keep your items high and dry.
A storage space with little hills and valleys is typically not level enough to make a good storage space. You may have to crawl in to flatten the hills and valleys in a specific area beneath the house to make it accessible for storage. As most of these areas are somewhat damp because of the lack of sunlight, any kind of handheld earth-moving tool might be all you need to create a flat spot to store your stuff in the crawl space.
Crawl Space Climate
Even if your crawl space is not subject to flooding, unless you live in a totally arid climate, the area beneath your raised foundation home has a higher humidity than outside of it. It may even be somewhat damp beneath the home. After finding a dry area to store your items, add a waterproof tarp on the ground or stack boards over low bricks to keep your stored items off the ground.
Plastic containers with tight lids keep your stored items safe from exposure in the crawl space underneath your home. Avoid using cardboard boxes in the area, as they tend to fall apart quickly when placed in the moist area. For even greater security, consider using the type of bag that you can suck the air from with your vacuum cleaner. Store these airtight bags inside plastic containers for the best results.