Kansas Nature Guide: September 2026
September is the great southbound river of monarchs and the second peak of the fall bird migration in Kansas. The prairie glows gold with goldenrod and asters, and the long, warm days are perfect for the road.
What to look for this week
- Bald eagles gather below the reservoir dams at Clinton, Milford, and Tuttle Creek, fishing the open tailwater as the lakes freeze.
- Order seed now around heat- and drought-tolerant Kansas crops, and plan the windbreak every prairie garden needs.
- The Quadrantid meteor shower peaks around January 3 in a short, sharp burst; look to the northeast after midnight from a dark Flint Hills sky.
- The bare cottonwoods along the creeks hold the conspicuous stick nests of red-tailed hawks against the gray winter sky.
Birds This Month
September is a superb fall birding month in Kansas. The shorebird migration continues strong at Cheyenne Bottoms and Quivira, where late pectoral, Baird's, and least sandpipers, lesser yellowlegs, and long-billed dowitchers work the mudflats alongside staging American white pelicans, Franklin's gulls, and the first returning ducks. Sandhill cranes begin to move through, and the wetlands fill with southbound waterfowl.
Songbird migration peaks in the river woods and prairie. Waves of warblers (Tennessee, Nashville, yellow, Wilson's, and more), vireos, flycatchers, and thrushes pass through the eastern timber, while Swainson's hawks gather into great migrating 'kettles' over the western and central plains — one of the season's grand sights. Common nighthawks stream south at dusk early in the month, and the scissor-tailed flycatchers flock and depart from the southern plains.
On the prairie, dickcissels mass into flocks before leaving, sparrows build up (the first returning Harris's, white-crowned, and Lincoln's sparrows arrive late in the month), and the last hummingbirds visit feeders before moving on.
This month's tip: watch the daytime skies over open country for the spiraling kettles of Swainson's hawks, and bird the river woods after a cold front for the densest warbler and migrant waves.
What's Blooming
September turns the Kansas prairie to gold and purple in the season's last great bloom. The goldenrods take over — stiff goldenrod, Missouri goldenrod, and tall goldenrod light up the Flint Hills, roadsides, and old fields with sheets of yellow — and with them come the asters: heath aster's white sprays, the lavender-blue New England and aromatic asters, and smooth aster across the tallgrass. The late dotted gayfeather still spikes purple in places.
The wild common sunflower — the state flower — is still blooming along every roadside and field edge, and the cultivated sunflower fields finish their golden display, their heads now nodding and going to seed. Ironweed, sawtooth sunflower, Maximilian sunflower with its tall leafy yellow spikes, and the last blazing star round out the show. The curing tallgrass — big bluestem turning bronze and copper, little bluestem reddening — sets off the flowers beautifully. September's golden prairie under the long, slanting light is one of the loveliest scenes of the Kansas year, especially across the Flint Hills.
Garden This Month
September is a gentle, productive month in the Kansas garden as the punishing summer heat finally breaks. The summer crops — tomatoes, peppers, okra, eggplant, and beans — often surge again in the cooler nights and keep bearing until the first frost, which arrives in late September or early October in the west and well into October across the rest of the state. Meanwhile the fall garden planted in August comes into its own: lettuce, spinach, kale, chard, broccoli, carrots, beets, radishes, and turnips all thrive in the cool, and many sweeten with the first light frosts.
The key autumn tasks begin now. Late September is the time to plant garlic for next summer's harvest, to sow cover crops (cereal rye, winter wheat, or clover) on emptied beds to hold the soil against the relentless winter wind, and to divide and plant perennials, trees, and shrubs in the warm soil and cooler air — fall is an excellent planting season in Kansas. Keep the fall crops watered if it turns dry, and ready row cover to carry tender plants through the first patchy frosts and extend the harvest.
Zone 5b (western and north-central Kansas): fall comes earliest here, with first frost possible in late September or early October. Harvest the fall crops, keep covers ready to extend tender plants through the first light freezes, and plant garlic late in the month for next year. Sow cover crops on emptied beds to hold the soil against the wind.
Zone 6a (central Kansas): the fall garden matures in the cooling weather. Keep harvesting summer crops until frost, and enjoy the fall greens, roots, and brassicas as the cooler nights sweeten them. Plant garlic toward month's end, sow cover crops on cleared beds, and divide and plant perennials in the warm soil and cooler air.
Zone 6b–7a (eastern Kansas — Kansas City at 6b, Wichita and the southeast at 7a): a long, productive fall. Summer crops keep bearing into October, fall greens and roots come on strong, and there is still time for a final sowing of fast greens and radishes early in the month. Plant garlic late, sow cover crops, and set out cool-season transplants.
What's at the Farmers Market
September markets in Kansas hold the bridge between summer and fall, still abundant. The late summer crops continue — tomatoes, peppers, eggplant, okra, sweet corn, beans, and the last melons — while the fall harvest arrives: winter squash, pumpkins, sweet potatoes, greens, and the first cool-season broccoli, cauliflower, and fall roots.
Apples come into full season from the orchards, the last peaches finish, and the markets fill with sunflowers and sunflower seed as the Sunflower State's signature crop is harvested. Local honey, eggs, grass-fed meats, and stone-ground flour remain, and the fall-decor crops — gourds, ornamental corn, and mums — begin to appear at the Lawrence, Topeka, Wichita, Manhattan, and Kansas City markets.
For selection and storage: choose apples that are firm with no soft spots and refrigerate them in the crisper, where most keep for weeks. Cure winter squash and pumpkins in a warm, dry spot before storing them cool and dry. Keep the last tomatoes at room temperature, and store sweet potatoes warm and dry rather than in the refrigerator.
Night Sky This Month
September brings the equinox and longer, cooler, comfortable nights to Kansas, a fine transition between the summer Milky Way and the autumn sky. The dark plains skies are at their easiest to enjoy now — the Cimarron National Grassland, the open Flint Hills back roads, and the Wilson and Webster reservoir country all spread the full sky beneath the wide prairie horizon, away from town glow.
The Summer Triangle still rides high in the early evening, and the summer Milky Way arches overhead before setting in the west, with the Sagittarius and Scorpius star clouds low in the southwest. In the east, the autumn constellations climb — the Great Square of Pegasus, Andromeda with its faint, naked-eye Andromeda Galaxy (the most distant object the unaided eye can see, easy from a dark Kansas site), and the W of Cassiopeia rising in the northeast. There is no major meteor shower this month, but the transition makes it a fine time for both summer and autumn deep-sky objects.
Because the planets shift each year, check the printable Kansas night-sky guide for this year's specific viewing nights and planet visibility from your latitude. The crisp post-front nights of September offer some of the steadiest, most transparent skies of the season.
Butterflies & Pollinators
September is the grand finale of the Kansas butterfly year — the monarch migration. The state lies squarely on the central flyway, and in late September a great southbound river of monarchs funnels through Kansas on its way to the Mexican wintering grounds, the orange wings streaming over the prairie and clustering at dusk in roost trees along the creeks. Planting and protecting fall nectar — and watching for the building flights — is the season's great butterfly event. Tagging stations across the state intercept the migration.
The migrants painted lady, common buckeye, and variegated fritillary are still abundant and also drifting south, and the sulphurs (orange and clouded), gray hairstreaks, and late skippers work the goldenrod and asters. To help the migrating monarchs, the late-blooming prairie is critical fuel — goldenrod, asters, ironweed, and the Maximilian sunflowers provide the nectar that powers the long flight to Mexico — so leaving these flowers standing and unmowed through September is one of the most valuable things a Kansas landowner can do.
Trees This Month
September begins the turn toward fall color in the Kansas woods. The earliest changes show along the creeks, where stressed and early cottonwood and black walnut leaves yellow and begin to drop, the walnuts releasing their green-husked nuts to thud onto the bottomland ground. The hackberries and green ash start to pale, and the sumac along the prairie edges and fencerows flares to brilliant scarlet — one of the first and brightest splashes of fall color in the state.
The mast crop drops in earnest. The bur oaks shed their large, fringe-capped acorns, feeding deer, turkeys, squirrels, and jays, and the Osage orange hedgerows begin dropping their heavy green hedge-apples along the old field boundaries. The eastern redcedars are full of ripening blue-gray berries. The tallgrass itself is turning — big bluestem to bronze, little bluestem to deep red — so that the cottonwood gallery and the curing prairie together carry the first warm colors of the Kansas autumn.
Go deeper with the Kansas guides
The complete Kansas birding, native-plant, wildflower, and night-sky guides — or the whole year in one bundle.
Same month elsewhere: September in Kentucky · September in Louisiana · September in Maine