October Gardening Tips for Southeastern Wisconsin

Seasonal Tips

October brings a crisp change to Southeastern Wisconsin—cool nights, brilliant foliage, and the promise of the first hard frost by month’s end (typically late October in Zone 5). This transitional period is perfect for wrapping up summer chores, tucking in tender plants, and laying the groundwork for a vibrant spring. Here are five essential tips to help you make the most of October in your garden:

1. Clean Up and Combat Disease

As foliage dies back, spent annuals, diseased leaves, and vegetable debris can harbor pathogens and overwintering pests.

• Remove spent foliage: Pull out tomato vines, pepper plants, and any annuals that have stopped producing.
• Inspect perennials: Cut back ornamental grasses to 4–6 inches and trim back hardy perennials like rudbeckia and sedum after foliage browns.
• Dispose wisely: Compost only healthy green material. Bag and discard anything showing signs of blight, powdery mildew, or insect damage to prevent reinfestation next year.
• Sanitize tools: Wipe pruners and shears with a 10% bleach solution or 70% isopropyl alcohol between cuts to avoid spreading disease.

2. Plant Spring-Flowering Bulbs

October is prime time for tulips, daffodils, crocus, hyacinths, and alliums. Planting now ensures robust root development before winter.

1. Choose quality bulbs: Look for firm, plump bulbs without soft spots.
2. Select sunny to part-sun locations: Most bulbs prefer at least 6 hours of light.
3. Prepare planting beds: Loosen soil to 8–10 inches, amend with compost or bulb-planting mix for good drainage.
4. Plant at correct depth: A general rule is three times the bulb’s height (e.g., a 2-inch bulb goes 6 inches deep).
5. Mulch lightly: Apply a 2-inch layer of shredded bark or leaf mold to regulate soil temperature and moisture.

3. Sow Cover Crops and Amend Beds

Bare beds left unattended are prone to erosion and nutrient loss. Cover crops protect and enrich your soil over winter.

• Best choices for SE Wisconsin: Winter rye, hairy vetch, and crimson clover.
• Timing: Broadcast seed in mid-October, lightly rake in, and water if dry.
• Benefits: Roots bind soil, add organic matter, suppress weeds, and fix nitrogen (leguminous varieties).
• Spring incorporation: In May, cut cover crops at bloom and work them into the soil as green manure for a healthy, fertile garden.

4. Protect Tender Plants and Containers

While perennials handle frost, many container plants and borderline-hardy specimens need extra care.

• Move pots: Relocate sensitive annuals, citrus, and tropicals to a garage, greenhouse, or bright basement.
• Insulate shrubs: Wrap the root balls of container-grown shrubs in burlap or bubble-wrap.
• Apply mulch: Heap 3–4 inches of straw or shredded leaves around the base of tender perennials (hostas, coral bells) to buffer against freeze-thaw cycles.
• Use frost cloth: Keep a roll on hand for unexpected late-month cold snaps; drape over vulnerable crops like lettuce or pansies overnight.

5. Lawn Care: Aerate, Overseed, and Feed

October is the sweet spot for promoting a thick, resilient lawn before winter dormancy.

1. Core aeration: Rent or borrow a core aerator to relieve compaction, especially in high-traffic areas.
2. Overseed: Spread a shade- or sun-mix, depending on your yard, focusing on thin or bare spots.
3. Fertilize: Apply a slow-release, high-potassium fertilizer (no “weed-and-feed” blends) around mid-October to strengthen roots.
4. Leaf management: Mow leaves with your mower’s mulching setting or rake them onto beds for composting—avoiding a thick mat on turf that can smother grass.

Looking Ahead to Spring

By tackling these October tasks—cleaning up, planting bulbs, cover cropping, protecting the tender, and fortifying your lawn—you’ll ensure your Southeastern Wisconsin garden weathers winter smoothly and bursts to life come spring.

For bulbs, soil amendments, frost cloth, and expert advice, visit Heritage Hill Nursery here in Cedarburg, or shop online at heritagehillnurseryinc.com. Here’s to a productive October and a garden ready for every season!