We have developed a method based on the Qiagen Genomics-Tip kit for the extraction of HMW DNA from a wide range of plants suitable for third generation sequencing platforms such as PacBio and Oxford Nanopore. This HMW plant DNA was used to make sequencing libraries with high insert N50 (30-40 Kb) for GridION and PromethION Oxford Nanopore machines and Sequel I and Sequel II PacBio machines. This HMW DNA is also suitable for PacBio HiFi libraries. The resulting sequencing data is ideally suited for de novo assembly of plant genomes.