Is regular garden soil suitable for raised beds?
Written by
Benjamin Miller
Reviewed by
Prof. Charles Hartman, Ph.D.Normal garden soil is often not suitable for use in a raised bed due to compaction and poor drainage. Unlike an in-ground garden, raised beds do not have existing soil layers that help regulate moisture. I have saved tomato beds from drowning in unamended soil within weeks. The ratio is simple: 30% compost, 20% drainage materials, and 5% worm castings will change any soil from a dead dirt to a luscious growing medium.
Compost Blend
- Role: Supplies nutrients and microbes
- Sources: Mushroom, leaf, or manure composts
- Quantity: 3 inches mixed into top 12 inches
Drainage Materials
- Role: Prevents waterlogging
- Examples: Perlite, coarse sand, or pine bark
- Quantity: 2 parts material per 10 parts soil
Worm Castings
- Role: Boosts microbial activity
- Application: Top-dress or mix into soil
- Frequency: Reapply every 60 days
Unmodified soil in raised beds turns into concrete-state soil. A trial showed amended soil had 3x more bell pepepers than native dirt. To test your mix, hold a handful and squeeze it together. If it holds shape but easily crumbles when poking, you have achieved the right texture. If you did not achieve this, add more perlite.
Try to avoid these mistakes: Excluded fine sand (to not impede airflow), did not test pH level, while overloaded with the manure. I fixed a bed that had 50% cow manure that burned the plants. It is a question of balance. I would test the soil's pH level every 30 days. You can use lime and sulfur to adjust your pH to keep the nutrients within range and accessible for plants.
Read the full article: 7 Expert Tips for Perfect Raised Bed Soil Every Time
