Here are three more cases where the standard gardening advice won’t do your plants any favors. (If you missed my previous posts on this topic, try typing “garden advice” into the search box at the top right of this page.)

Vitamin B₁ stimulates root growth. No, it doesn’t. A study done in the 1930s showed that when disembodied pea roots were placed in a petri dish saturated with vitamin B₁ (thiamine), they grew. From this, they concluded that pouring a vitamin B₁ solution over newly transplanted plants would help them get established. However, the plants in your garden are not detached pea roots, and they’re not growing in a petri dish. Further research has shown that adding B₁ does nothing to help reduce transplant shock, but it will have an effect on your wallet. If you want to encourage roots, look for a product containing a rooting hormone instead.

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