How to Soften Clay Soil Without Damaging the Bulbs

Dig up flower bulbs before amending clay soil.

Clay soil is heavy, doesn't drain well and easily compacts around plant roots. While it's easy to break it up and amend it each year in annual flower and plant beds, in perennial beds there is concern about damaging the plants while amending. Perennial bulb beds require more work, but the plants are less likely to be damaged compared with other perennials because they are completely removed before fixing the clay soil. Amend clay soil for spring bulbs in summer once the plants have died back and amend summer bulb beds in spring before replanting the tender bulbs in summer.

Things You'll Need

• Trowel
• Power tiller
• Hoe
• Compost
• Shredded bark
• Soil test kit
• Fertilizer
• Mulch

Instructions

1. Dig around each bulb then slide your trowel under it and lift it out. Set spring bulbs in a cool, dry room while you are amending and store summer bulbs over winter in a dry place as usual.

2. Remove all spent plant material that remains in the bed. Till the bed to a 10-inch depth using a power tiller or hoe to break up any compacted soil.

3. Lay 4 inches of compost and 2 inches of coarsely shredded bark over the entire bed. Till it in to a depth of 10 to 12 inches.

4. Perform a soil test to determine fertilization needs or use a general purpose bulb fertilizer following label application instructions. Work it into the soil with the hoe then level the bed so water doesn't collect in low spots.

5. Replant spring bulbs immediately after amending and replant summer bulbs in spring once frost danger has passed. Replant only healthy, undamaged bulbs in the bed, spacing them as recommended for each flower type.

6. Lay an additional 2 inches of bark mulch over the beds after replanting. The mulch preserves soil temperature and moisture while also adding necessary organic matter to the clay soil as it breaks down.

Tips & Warnings

• Planting on a slight slope aids drainage in heavy clay gardens.

• Spring bulbs can be stored until fall if you can't amend the bed right away in summer.

• Sand may help break up light clay soil but will make heavy clay soils cement-like.

References

• University of Minnesota Extension: Amending Soils For Perennial Beds
• University of Illinois Extension: Bulb Basics