Grow & Cook Your Own Potatoes Fresh From The Vegetable Patch First Earlies: If planted in Autumn would be ready to harvest within 10-12 weeks. Also has a good all-round tolerance to diseases to Common Scab & Blackleg. a waxy type potato, great for boiling & for salads. Pentland Javelin is considered to be one of the finest First Earlies that you can grow. Produces heavy crops of short oval white skinned potatoes & has a pure white, tasty, flesh.