Planting in old tree stumps
I've had 3 old tree stumps in my garden for a number of years and recently decided to try to make a feature of them. I placed them all together and added some general compost in the middle and planted a couple of herbs. A few weeks on the herbs have died so I'm wondering why this has happened when to my mind it's not really much different to putting them in a pot. Or so I thought! Should I have put some lining in the stumps too? I like the way the feature looks now so would like to try some other plants but obviously don't want to make the same mistake. Any advice please?