What's the optimal compost application method for gardens?
Written by
Liu Xiaohui
Reviewed by
Prof. Martin Thorne, Ph.D.Applying compost properly ensures maximum benefit for different areas of the garden. In new beds, it is necessary to incorporate deeply, while established plants benefit from top-dressing. Other mixtures are required for composting in containers. For lawns, the best effect will be obtained from thin applications during the periods of growth. In all cases, ensure that you select the method best suited to the specific needs of the garden.
Vegetable Beds
- New beds: Rototill 3-4 inches compost into top 12 inches
- Established beds: Top-dress 1 inch before planting season
- Frequency: Reapply after heavy-feeding crops like corn
Perennial Gardens
- Spring application: 1-inch layer around plants avoiding stems
- Fall preparation: Mix into soil when dividing plants
- Special care: Use ericaceous compost for acid-lovers
Container Plants
- Soil blend: 30% compost + 60% potting mix + 10% perlite
- Refresh method: Top-dress 0.5 inch every 6-8 weeks
- Repotting: Replace 25% of old mix with fresh compost
New garden beds require deep incorporation of compost. Mix in 3-4'' well into the top foot of soil. This creates a nutrient-rich root zone for young plants. Avoid distinct layering as it inhibits root penetration. I use a broadfork to incorporate without damaging the soil structure.
Established plants benefit from the technique of top-dressing. Apply a 1-2 inch layer around perennials and shrubs, taking care to keep it away from the plant stems. Earthworms will incorporate it into the soil, maintaining the soil's structure. This practice also helps feed the plants. The timing of materials added is important; apply before heavy rains for natural watering. Top-dressing materials should be used annually for continuous improvement.
Plants in containers require careful mixing of the compost to ensure optimal growth and development. Use a 30% compost, 60% potting soil, and 10% drainage material mixture. This prevents soil compaction and overfertilization. Renew the top of the containers with a 0.5-inch layer of top-dressing every month during the growing season. Always sieve the compost before using it in a container to remove lumps.
Lawn applications require detail. Use 0.25-0.5 inches during overseeding in the fall. A drop spreader permits even coverage. Water is immediately applied to wash down particles to the soil level. This builds better soil biology without smothering the grass. Do not apply in the spring when competition from pre-emergent weeds is present.
Read the full article: Choosing the Best Compost for Gardens
