What's the difference between potting soil and potting mix?
Potting soil and potting mix are often used interchangeably, but technically potting mix is soilless (containing peat, coir, perlite, and vermiculite) while potting soil may contain actual dirt. For containers, soilless potting mix is preferred because it's lighter, drains better, and is less likely to harbor pests and diseases. Most quality commercial products labeled 'potting soil' are actually soilless mixes.
Can I use garden soil in containers?
No - garden soil is too heavy and dense for containers. It compacts, drains poorly, and can introduce pests, diseases, and weed seeds. Container roots need the light, fluffy structure of potting mix to breathe and grow properly. Even mixing garden soil with potting mix creates problems. Always use a quality commercial potting mix or DIY blend designed for containers.
How often should I replace potting soil?
For most containers, refresh or replace potting soil annually. Over time, soil breaks down, compacts, and loses its air spaces. Nutrients become depleted and salts from fertilizers accumulate. For perennials in large containers, you can top-dress with fresh compost and replace the top 2-3 inches annually, with complete replacement every 2-3 years.
Should I add fertilizer to fresh potting soil?
Most quality potting mixes include starter fertilizer that lasts 2-6 weeks. Adding fertilizer immediately can burn young roots. Wait until plants are established and showing new growth before supplementing. Read the bag label to see what's included. Premium mixes like FoxFarm may not need additional fertilizer for a month or more.
Why is my potting soil not absorbing water?
Dry peat-based potting soil becomes hydrophobic - water beads up and runs off instead of soaking in. Soak the entire container in a tub of water for 30 minutes, or add a few drops of dish soap to your watering can to break surface tension. For prevention, never let potting soil dry out completely. Add coconut coir or vermiculite to improve wetting.
Is peat moss bad for the environment?
Peat bogs are important carbon sinks that take thousands of years to form. Harvesting peat releases stored carbon and destroys habitats. Many gardeners are switching to coconut coir, which is a renewable byproduct of coconut processing. Several brands now offer peat-free alternatives that perform equally well. Consider your environmental priorities when choosing.