Using one predator for every 20 spider-mites usually brings control within 3 weeks.
Parasites come as eggs ready to hatch.
Use at least 1 for every square foot of gardening area. Repeat 4 times at 2 week intervals for best results. This gives control in about 1 month. One release may give eventual control, but more slowly. Sold as adult ladybugs and are ready to use.