培土 has two senses. As a noun, e-commerce listings of garden products (
营养土,
多肉培土,
兰花培土) use it to mean 'cultivation soil / potting mix'. As a verb,
给…
培土 means 'to mound earth around the base of a plant', a key step for potatoes, scallions, and leeks. CC-CEDICT only lists the verb sense.
