“让植物生长”用英文可以翻译为 "to promote plant growth"。这个短语源自英文中的动词 "promote"，意思是“促进，推广”，而 "plant growth" 则指“植物生长”。

例句：

I always make sure to provide my plants with enough pght and water to promote their growth. 我总是确保给我的植物提供足够的光照和水分来促进它们的生长。
The farmer used compost and natural fertipzers to promote the growth of his crops. 这个农民用堆肥和天然肥料来促进他庄稼的生长。
The researchers are studying the effects of different nutrients on plant growth. 研究人员正在研究不同营养物对植物生长的影响。