Poodles are known for their luscious, curly hair. If you don't clip it, a poodle's hair will naturally grow as long as you let it. However, it can easily get matted if you don't take good care of it as it's growing. You can help the hair grow in strong and healthy with a mixture of grooming and dietary supplements.
Brush and comb your poodle every day. There is no way around this. The longer a poodle's hair gets, the more likely it will be to tangle and mat -- and if the mats get too bad, you'll have to cut the dog's hair and start from scratch.
Trim the poodle's hair every so often to keep the ends healthy. You can trim the whole body with dog clippers, or you can use the clippers to create a specific poodle cut. Poodle hairstyling takes some experience, so it's best if you watch a groomer do it the first time.
Give your poodle a rinse with diluted apple cider vinegar when you bathe it. According to Earth Clinic, apple cider vinegar is very healthy for a dog's skin and fur. It prevents hot spots and other skin ailments that could harm the hair from popping up. You can also put some apple cider vinegar in your poodle's water.
Give your poodle dietary supplements that help the hair grow. Omega-3 fatty acids are very beneficial, according to the University Of Florida veterinary medicine school. These fatty acids can be found in flax seed, fish oil and hemp oil, among other things. Buy a jar of fish oil capsules and give one to your poodle every day.
Give the poodle plenty of exercise. A dog's coat is only as healthy as the dog. Walk or play fetch with your poodle at least once a day. Look out for mud, though, if you don't want to clean its coat.