How to check if your potting soil is toxic

If you sterilize your own potting soil – or even if you have reason to suspect potting soil you bought or already have – it is useful to check to ensure that the potting soil is not toxic before you go through the work and expense of planting your garden using it. Fortunately, it is relatively easy to test, and only takes a few days.

Place some potting soil into a pot, and plant it with lettuce seeds (or other seeds with a similar high germination rate), since they germinate quickly, then watch to ensure that the seeds to germinate.

If the lettuce does not begin to sprout within a few days, your soil is very likely toxic and you should discard it or use it in your compost instead.