Now
31°C · Partly cloudy
Today
32° / 19°
Soil 6 cm
25°C
First frost
~43 days (Oct 21)
Gardening in Des Moines
AI field guide · refreshed weeklyDes Moines Gardening: Early Fall Planting & Harvest Window
Zone 5a means your first fall frost arrives around October 21—43 days away. Soil at 25°C (77°F) is still warm enough for cool-season crops to germinate and establish before winter dormancy. Spring frost typically hits April 21, so you're 140 days past that threshold. This is prime time to sow fall vegetables that need 4–8 weeks to mature before hard freezes.
Sow outdoors now
Spinach & Arugula
Sow directly into soil this week; both germinate in 7–10 days at 25°C and mature in 30–40 days before frost. Choose 'Space' spinach or 'Roquette' arugula for reliable fall crops.
Radishes
Plant 'Cherry Belle' or 'French Breakfast' for harvest in 25–30 days; they thrive in cool soil and tolerate light frosts. Sow every 2 weeks through late September for succession harvests.
Lettuce & Mesclun Mix
Direct-sow leaf varieties like 'Buttercrunch' or 'Lollo Rosso'; they'll be ready in 35–45 days and actually sweeten after light frosts. Broadcast mesclun mixes for quick salad greens.
Kale
Sow 'Lacinato' or 'Winterbor' now for harvest starting in 6–8 weeks; kale improves in flavor after frost and can overwinter in zone 5a if mulched heavily.
Turnips & Rutabagas
Direct-sow 'Purple Top White Globe' turnips (60 days) or 'Laurentian' rutabagas (90 days) for storage crops; both handle frost and store well into winter.
Start indoors now
Brassica Transplants (Broccoli, Cabbage)
Start 'Packman' broccoli or 'Early Jersey Wakefield' cabbage indoors now for transplanting in 3–4 weeks; they'll mature before hard frost and tolerate cool nights.
Garlic Cloves
Begin stratification indoors in moist sand or peat now; plant cloves directly outdoors in late September–early October for spring harvest. Choose hardneck varieties like 'German Extra Hardy' for zone 5.
Mâche (Corn Salad)
Start seeds indoors in small pots; transplant seedlings outdoors in 3 weeks for a cold-hardy winter salad green that survives zone 5 winters under mulch.
Harvest now
Tomatoes & Peppers
Pick all mature and near-mature fruit before the first frost (Oct 21); green tomatoes ripen indoors in 2–3 weeks at room temperature. Leave peppers on plants as long as possible—they sweeten in cool weather.
Summer Squash & Zucchini
Harvest daily while tender; plants will slow production as nights cool but may produce until mid-October. Remove any diseased leaves to extend plant life.
Beans (Bush & Pole)
Pick pods regularly to encourage continued flowering; most varieties will produce until the first hard frost. 'Provider' bush beans often yield a second flush in fall.
Tasks this week
- Deadhead spent flowers on perennials and annuals to redirect energy into root storage before dormancy.
- Mulch around garlic and onion beds with 5 cm (2 in) of compost to insulate soil and suppress winter weeds.
- Scout for Japanese beetles and squash bugs; handpick or use neem oil on remaining warm days—populations crash after the first frost.
- Cut back perennials like coneflowers and black-eyed Susans to 10 cm (4 in) after frost kills foliage; leave ornamental grasses standing for winter interest and wildlife shelter.
- Drain and store garden hoses and irrigation lines before hard freeze; flush lines to prevent ice damage.
Watch out for
- Frost risk: Although 43 days remain, a surprise early frost can occur in zone 5a; cover tender plants on nights when temps dip below 4°C (40°F).
- Powdery mildew and early blight thrive in cool, humid fall weather—remove affected leaves and improve air circulation around tomatoes and squash.
- Slugs and snails explode after rain; the 23 mm (0.9 in) forecast for Sept 9 will trigger activity—handpick at dusk or use beer traps in vulnerable beds.
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