Boiling Water Treatment Water is the mainstay of plant growth and reproduction. The temperature of the water determines whether the plant lives or dies. Warm or cold water do little damage to most plants and benefit weeds. Boiling water not only kills the plant but also the seeds that may lay dormant in the soil. The boiling water produces almost instantaneous results. The heat destroys the plant and root tissue, causing instant shock. The plant withers and dies within a day or two. Boiling water works well for walkways and garden paths or driveways. But you must use care in the lawn or garden to avoid the hot water splashing on the remaining plants or grass. https://homeguides.sfgate.com/salt-water-mixture-kill-weeds-grass-flowers-36440.html