Yes, you should cut roots off bulbs before storing them, but trim to about one inch rather than cutting flush to the base. That short stub protects the bulb's core tissue from rot while keeping the root mass small enough to store clean and dry.
I learned this the hard way with a batch of stored dahlias a few years back. I cut the roots right down to the tuber body, leaving no stub at all. By January, over half of those tubers had soft brown spots right where I made the cuts. The clean cuts turned into open doors for rot. The dahlias where I left about an inch of root came through winter in much better shape with firm, healthy tissue.
The biology behind this is straightforward. Roots left too long trap moisture and soil particles that carry fungal spores. Those spores sit against the bulb for months and have plenty of time to take hold. On the flip side, cutting too close creates a fresh wound that exposes living tissue. That wound becomes an entry point for infection during the long storage period.
Trimming bulb roots for storage is just one part of cleaning bulbs before storage. USU Extension recommends cutting dahlia stalks to four inches above the tuber. Gladiolus stems get trimmed to two inches. The same careful approach applies to root systems below the bulb. Leave a short stub and let it dry out during the curing phase before you pack things away.
Use Clean Sharp Tools
- Scissors or pruners: Use sharp bypass pruners or clean scissors so you get a smooth cut every time.
- Disinfect blades: Wipe your tool with rubbing alcohol between bulbs to stop disease from spreading through the batch.
- Avoid tearing: Never pull or rip roots off by hand because ragged tears damage more tissue than a clean cut does.
Cut at the Right Angle
- Slight angle: Make each cut at a small angle so water rolls off the stub instead of pooling on a flat surface.
- One inch mark: Measure about one inch from the bulb body and trim there for the safest balance of short and protected.
- Work in batches: Line up several bulbs and trim them all at once so you keep a steady rhythm and consistent length.
Protect Fresh Cuts
- Dust with sulfur: Sprinkle garden sulfur powder on every fresh cut surface to create a barrier against fungal infection.
- Let cuts dry: Set trimmed bulbs on newspaper for two to three days so the cut ends can callus over before packing.
- Check before packing: Feel each cut end to make sure it has hardened and dried before placing bulbs into storage.
Bulb root preparation goes hand in hand with the curing stage. Once you trim the roots and dust the cuts, give the bulbs about one to two weeks in a warm, dry spot at 60°F to 70°F (15.5°C to 21°C) before packing them for winter. This drying period lets cut surfaces seal and toughen up.
In my experience, the biggest mistake gardeners make is skipping the sulfur powder step. That small extra effort blocks most of the common fungi that cause storage rot. You can find garden sulfur at any nursery for a few dollars. A single bag lasts for years because you only need a light dusting on each cut.
Take the time to trim and prep your bulbs the right way before you store them. A clean one-inch stub, a dusting of sulfur, and a proper cure period give your bulbs the best shot at making it through winter. You'll thank yourself when spring arrives and every bulb you open feels firm and ready to grow.
Read the full article: Storing Bulbs: Full Guide for Better Blooms
