Words of caution about using various soil components
Years ago, professionals in the plant world learned that growing above ground is completely different than growing in the earth. The most important discovery in the history of container gardening - straight soil won't work in containers. It's too dense, often harbors unwanted microorganisms, and is full of weed seeds just waiting to germinate.
So, the first thing to avoid to prevent soil problems, is using soil. With that in mind, here are a few other tips for avoiding problems with your "growing media:"
- Be sure to completely moisten your mix before putting it in a container with plants.
- Don't leave an open bag of mix laying around all year and expect to use it again - it'll dry out and deteriorate.
- Straight compost is too heavy for containers - it doesn't drain well, and you'll end up with a concrete block if it dries out.
- Don't use mixes called "soil-less" for planting adult plants - they are for use with starting seeds and young plants.
- Don't assume all plants want the same mix. Different plants need different amounts of drainage, nutrients, and pH levels. Pay attention to your plant's special needs.
- If you are mixing your own and are using peat, coir, or another form of organic material - check the pH. You may need to add lime to keep it from being too acidic.