If you have a dirt-caked patio, they are relatively easy to clean. You will probably need a high-pressure power hose, which you can rent from a hardware store. If you don't want to deal with it, there are many companies that specialize in cleaning outdoor areas, including patios.

The following are some tips for how to clean a dirt-caked patio.
1. First, move everything off of the patio. This includes furniture, toys, potted plants, grills, and anything else that may be on there. You may also want to set them aside for a cleaning of their own; chances are, if your patio is dirty, your furniture probably isn't too far behind it.
2. Once all items are cleared off of the patio, sweep the entire area with a strong broom to remove loose dirt, weeds, and debris. The best kind for this type of job is an outdoor push broom, which you can find in your local hardwood store. Sweep the patio thoroughly, making sure to get the corners as well.
3. If you have weeds growing through cracks in your patio or in the caked dirt, you will need to weed them. If left alone, these weeds could grow substantially and cause cracks in y our patio, or make current cracks even bigger. If weeds are deep into the cracks, you can spray weed killer on them. Be sure to read the instructions and follow them carefully.
4. Once you have completely prepped the patio area, you will now need to wash it. If the dirt is not caked on too heavily, you can do this with a regular garden hose. However, if you have a dirt-caked patio, you will most likely need to use a power hose or a power scrubber on it. If you know someone who has one, borrow it from them, or you can rent one inexpensively for the afternoon from your local hardware store. The power hose or scrubber should be able to clear off any caked-on dirt that is on your patio.
5. With your patio now clean and free of dirt, take inventory of the condition of the concrete, stones, bricks, or whatever type of material it is made from. If there are cracks, chips, or missing stones, it is a good idea to repair these if you plan on using your patio frequently this summer. Otherwise, the continual foot traffic and furniture could make it even worse.

When cleaning your patio, it's also a good time to clean your patio furniture as well. You probably won't need a power hose for this, but a regular garden hose and some soapy water should be enough to clean off any dirt, leaves, cobwebs, and debris from your patio furniture. If you have upholstered or cloth patio furniture, you can buy special cleansers for cleaning them.

Cleaning your dirt-caked patio in the way described above will help to make it a cleaner, more pleasant place to spend time during the summer.