Spider mites like dry climates and reproduce every 5 days in temps over 80 degrees. Lower your temps to 60 degrees to create a hostile environment and spray, especially under leaves, with a jet of cold water. This interrupts their reproductive cycle and gives you a chance to kill the fuckers. Remove leaves with more than 50% damage. You can smear Tanglefoot around the lips of containers and stems to create a barrier they can't cross. This way you can isolate affected plants and it won't spread to your entire garden. Make sure there is no touching between the leaves of affected and unaffected plants. If you want chemicals, neem oil and einstein oil are what I use. Oh yea, keep an oscillating fan trained on your plants as well.
Homemade sprays often aren't strong enough to completely destroy a bad infestation but if you are low on money, or want to stay organic, try garlic, hot pepper, citrus oil, and liquid seaweed. If this doesn't help and you want to stay organic, a nicotine spray will absolutely destroy them. Remember, this is a product people will be consuming, it's best to keep your chemicals to a minimum.
Eggs hatch in 5-8 days so follow up every 4 days with continual sprays until the problem is under control. Good luck!