There is no definitive answer to the question of which is best to use ginger for hair growth, young, old or yellow ginger, as there are slight differences in efficacy and application between the different types of ginger. Here is some information about these three types of ginger for reference:

1. Tender Ginger: Tender ginger is often considered a hair product, with pungent and dispersing properties. In Traditional Chinese Medicine (TCM), they are commonly used to treat colds, coughs, stomach chills, and other ailments. Due to the pungent taste of young ginger, squeezing out the juice to apply may not be suitable.

2. Old Ginger: Compared to young ginger, old ginger is milder in nature and has higher medicinal value. They are often used to treat symptoms such as indigestion, stomach pain, and diarrhea. Older ginger also has a softer taste, so try juicing it and applying it.

3. Yellow Ginger: Yellow ginger is similar to old ginger in nature but has a softer flavor. They are often used to treat symptoms such as colds, coughs and stomach chills. Yellow ginger also has some sweating properties that can help the body expel excess moisture.

Overall, when using ginger for hair growth, you can choose any of the above three types of ginger. If your personal taste prefers a spicy flavor, you can choose young or old ginger; if your taste prefers a softer flavor, you can choose yellow ginger. Also, whichever type of ginger you use, juicing it and applying it may be more conducive to the absorption of the active ingredients.

Please note that while ginger can be used as a natural remedy in some cases, caution should still be exercised when using it. Especially for people with special health conditions (e.g. diabetics, pregnant women, people with high blood pressure, etc.), it is recommended to consult a doctor before use. In addition, some of the ingredients in ginger may interact with certain medications, so always consult your doctor before taking any medication.