Garden furniture is a big investment and not something you will want to replace often. With proper care and cleaning, you should get years of enjoyment from your garden tables, chairs and benches. When new garden furniture is purchased, often a care leaflet is included. This info is easily lost over the years. Since outdoor garden furniture comes in a wide variety of materials, there are many different approaches to maintenance. Most garden and patio furniture can be cleaned with mild soap and water. A pressure washer with between 1200 to 1300 psi is useful for cleaning many types of garden furnishings, but be sure to use a low setting as varnish, paint or powder coat finishes could be removed accidentally.
Wood garden furniture that has been finished with a exterior grade varnish can be cleaned first and re-treated if weathered or worn after it is completely dry. Wood garden furniture is best stored indoors over winter except for teak and cedar which have natural preservatives in the wood.
Garden umbrellas require some lubrication after being in storage usually. Check the joints and moving parts. Use a spray or drop lubricant on metal frames and bar soap or paste wax on wooden umbrella frames. Be sure to avoid getting it on the umbrella's fabric cover. Wash the covers using a soft bristle brush and a mild soap or detergent.
Cushions covered in fabric can be scrubbed with a soft bristle brush and rinsed with water. Allow to dry completely before putting into use or storage. Some types of cushions are mildew resistant and can be scrubbed with a solution of 1 cup bleach, 1 cups detergent, gallon of water. Mix and spray on the cushion and allow it to soak for 30 minutes, then scrub and rinse with water and allow to dry completely. When storing fabric cushions, never wrap them in plastic. Plastic does not breathe and you are much more likely to get mildew.
Fabric from garden chairs and hammocks can often be washed in the machine on a gentle cycle. You can add bleach for white items. To avoid shrinkage, stretch the fabric that goes on frames back in place while damp. Be sure to clean or treat the frames before the fabric is put back on. Store fabric outdoor furniture indoors off season.
Wicker garden furniture can usually be cleaned with a garden hose and bristle brush to dislodge the debris that gets in the weave. Do it in full sun if possible on a dry day so that it dries quickly. When dry, you can apply a paste wax to the frame to help keep it clean and water resistant. Be aware though that the effect of water on paste wax can leave whitish spots, like the rings that cold beverage glasses leave on polished furniture. If the wicker is unpainted, a product like Thompsons Water Seal might be a good choice for exposed frames and worn areas.
Resin or Poly garden furniture is the easiest in the care dept. A product designed to clean boats, like Greezed Lightning, melts body oils and grime. Just be sure to do it outside and rinse well. Most general purpose cleaning sprays like 409, or Fantastic do a good job too, just don't let them sit on the finish for long. On a tough stain, you can sand past the stained finish with fine grit wet-dry sandpaper or abrasive powdered cleaner and polish the surface with paste wax to help re-finish where you have sanded. Mildew can be removed with a spray like Tilex, but just wash clean immediately.