IN YEARS WHEN it rains consistently, here is what I do in September, I promise: divide and also add perennials (leaving room for bulbs next month); plant shrubs and trees; repair or renovate lawns; fight next year’s weeds (which slip out of moist ground easily). This year has been positively sodden, too much of a good thing, which presents its own challenges (the 2022 growing season had been dry, dry, dry, its own form of test).

Rain or no, I’m under way on some key September chores, like putting up harvests, turning the compost, and even saving seed. September is also perhaps the best month of all to really look at the garden critically, taking stock of its strengths, weaknesses…and opportunities–like how many great late-blooming perennials do I have (and could I add more)?

That I am doing, but in the hopes of tackling the rest of it successfully, I am always eager for some predictable precipitation come September (and please, not 3 inches in an hour or two!). I’m revamping more large sections of the garden—some of the oldest beds here are long past prime, and I’m trying to rehab one at a time, including removing swaths of decades-old groundcovers that now just look like thugs. I’d love to make it easier on all the divisions and transplants I’ll be creating in the process, and typically time such work for cool, moist times. But onward we each shall have to go shortly in our fall garden tasks, I guess, weather or not.

HERE IN ZONE 5B, where frost can come as early as late September, you’d think I’d be feeling more as if the season’s “end” was in sight. But I work to load the landscape with elements of a 365-day garden, remember? My goal is a garden that colors up extra-early, keeps showing off till hard frosts say “slow down,” and even has strong structure to carry me visually through winter.

Take inventory—walk around, make notes—and plan in detail to extend and enrich your garden’s season. Reviewing some of my recent tip-filled interviews with landscape designers like these may help. Or maybe you want to make a meadow or a meadow garden, or concentrate on adding natives that particularly appeal to pollinators? That story. (Or figure out what to consider “native” where you garden, anyhow.) Or creating a garden that the birds love. Or the butterflies. Whatever your goal, begin planning now.

garden elsewhere? regional links

THE ORGANIC-GARDENING approach and the how-to tips I offer apply most anywhere–pruning a rose or sowing a tomato seed is similar, wherever the rose or tomato may grow. But the when is not the same. To adjust timing: My garden is in Zone 5B, in the Hudson Valley (NY)-Berkshires (MA) area, where frost can persist well into May and return in October. You may need next month’s chores, or last month’s (the archive is here). For more Zone-specific advice, I’ve rounded up links to calendars and checklists from around the nation (and the U.K.). But read on first, because I’m betting there’s something here for you, wherever you may dig, weed, or prune.

harvest-stashing ideas

PROCESS TOMATOES the easy way: roasted then frozen for use later as sauce or to make soup; as easiest, skins-on freezer tomato sauce; even just whole in freezer bags for soups and stews (instead of buying canned tomatoes for that purpose).

TOMATOES, ZUCCHINI AND CORN are in their peak harvest, so with cookbook author and friend Alexandra Stafford we rounded up a glut of recipes for those ingredients.

GOT GREEN BEANS? I freeze green beans in tomato sauce—or at least some of my harvest that way—and enjoy this extra-ingredient sauce in the offseason when a crunchy green bean is a welcome treat.

MAKE PICKLES (refrigerator dill, or hot-packed bread and butter).

I FREEZE MANY HERBS, too, including parsley, rosemary and chives, or make them into pestos to freeze as well. Here’s how. If it’s vegetables you are storing, start here. Lots more harvest-stashing recipe ideas, including frozen peaches.

HERBED SALTS and flavored vinegars are another way to use the harvest—and make great holiday gifts. Some recipes.

well-timed weed and pest control/prevention

WEED WAR! Now is the time limit next year’s weeds. I love the expression: “One year seed, seven years weed.” Don’t let them set seed! Some species are actually easier to thwart in late summer and fall, like these (including knotweed, ragweed, Ailanthus, bindweed, curly dock and more).

SPECIFIC WEED WISDOM:

• How to ID your weeds—links to online guides
• The weed encyclopedia of all weed encyclopedias
• A 101 approach to weed control
• Smothering weeds with cardboard and newspaper
• Will you use chemicals, or home remedies? (Do the latter really work?)
• Piling on the mulch for weed suppression and control
• Poison ivy 101
• Clearweed, or Pilea pumila
• Hedge bindweed and spotted spurge
• Garlic mustard, Alliaria petiolata
• Galinsoga and Commelina
• Mat-forming driveway or crack-and-crevice weeds: liverwort and pearlwort
• A weed I accidentally planted, Houttuynia or chameleon plant
• All my weed stories

PEST PROBLEMS? When you start your fall cleanup, do so with pest control in mind, too. Deer, voles, cabbage worms, squash bugs and other garden pests can be limited with tactics like this. Extra-thorough care now means fewer issues next season.

ONE YEAR I was knee-deep in rabbits; the next year it’s voles. (I always have a billion woodchucks, year in and out.) Need a 101 on “nuisance wildlife” control? Ohio State’s Marne Titchenell shared her expert advice.

lawns (and crabgrass)

THE WAY WE MOW—in fall, and throughout the active growing season—and when we do our raking up affects how many lawn weeds grow, particularly opportunists like crabgrass. Repair compaction, minimize weeds and overseed now.

vegetable garden

GREEN TOMATOES? Encourage your tomatoes to ripen faster (yes, you can help!). I’ve got a range of tactics (plus some advice on where and how to ripen ones you pick early to protect from chipmunks or frost).

READY FOR 365-DAY vegetables, even up North? This year-round approach from Niki Jabbour, who grows 30 crops to harvest November through March in Halifax, Nova Scotia, lays out the basics if you’re ready to meet the challenge.

MY FALL VEGETABLE GARDEN PLANS were covered in this article, remember? Still ahead to plant here: more salad, garlic (next month) and spinach, at least…and maybe some radishes. How you can plan for an extended harvest in every region.

SAVE SEED: The time is now for saving tomato seed (and other “wet” seeds such as peppers, squash, cucumber, melon). How to save tomato seed.  Beans, peas, and lettuce are easy to save; cucurbits are, too, if you know how extra-ripe to let the fruits get first. How to save all those, with Seed Savers Exchange.

SEND IN SOIL SAMPLES for testing if you’re seeing poor results in some beds. Here’s why, and how. Contact your local cooperative extension on where to send samples.

AS AREAS COME EMPTY from harvest, build vegetable-garden soil by sowing cover crops. These “green manures” will be turned under to improve soil tilth and fertility. Don’t sow in areas reserved for fall-planted garlic, or very early spring crops.

GARLIC should be curing or stored in an airy, sheltered place. Read all about growing garlic, and storing your harvest–and order bulbs now for October-ish planting, if you don’t have your own stash to use.

KEEP ASPARAGUS well weeded and watered, too. Let asparagus ferns grow till hard frost, when they are fully browned—or even leave them up till spring cleanup.

TOMATO, CUKE OR SQUASH TROUBLES? Tomatoes have a range of possible problems, and among them is the feared late blight (a story on that, from Cornell pathologist Dr. Margaret McGrath). If your issue is cucumbers or summer squash, start here. Peppers can be tricky in some seasons (though in my region, not this year, which has been hot-dry); pepper tips and recipes and storage tips.

flower garden

USE BULBS CREATIVELY. I got some advice from two artistic and expert gardeners at the public space called Chanticleer in Pennsylvania: From Lisa Roper, on planning clever combinations with dramatic perennials that create bulb backdrops and also hide fading bulbs foliage. And from Jonathan Wright, on bulbs in lawns, pots, and other unexpected and welcome spots.

ORDER BULBS promptly, and plant as they arrive (lilies most urgently). Have color from bulbs from earliest spring onward, if you plan like this. Top 7 tips on shopping smart for flower bulbs.  Many bulb-growing questions are answered in my Bulb FAQ.

THINK ABOUT what I call “making mosaics,” about creating mixed tapestries of ground-covering plants for beauty and ease of maintenance. Marietta O’Byrne inspired some ideas on that score.

DON’T DEADHEAD FADED perennials, biennials and annuals if you want to collect seed (non-hybrids only) or let some self-sow. Nicotiana, annual poppies, larkspur, clary sage, tall verbena (V. bonariensis) and many others fall into this leave-alone group. So do plants with showy or bird-friendly seedheads, like coneflowers, some sedums, clematis and grasses. And some perennials are actually in their prime right now, like these beauties.

DAYLILIES can be dug and divided as they complete bloom, right into fall, if needed.

PEONIES are best divided and transplanted in late August through September, if they need it. Peony master Jeff Jabco of Scott Arboretum at Swarthmore College shared all his best tips for planting and growing them. Remember with these fussy guys that “eyes” must not be buried more than an inch or two beneath the soil surface.

SOME FAMILIAR ANNUALS are better overwintered as rooted cuttings rather than by nursing along leggy older specimens. Geraniums, coleus, wax begonias, even impatiens (to name just a few common ones), if grown in good light indoors and kept pinched and bushy, will yield a new generation of cuttings for spring’s transplants—but expend this serious effort and space on an unusual form of something, not the garden variety.

IF TUBEROUS BEGONIAS or other bulb-like things start to go slack, let them dry off and rest early, or they will rot. Take your cue from the plants! I move my pots under cover so rain doesn’t contribute to sogginess. Growing tuberous begonias.

PREPARE NEW beds for fall planting by smothering grass or weeds with layers of recycled corrugated cardboard or thick layers of newspaper, then put mulch on top.

RE-EDGE BEDS to make a clean line and define them. Don’t let them get overrun just because summer’s wound down. A clean edge makes a big difference.

trees and shrubs

ON THE DRY SIDE? In dry years here, my century-old apples began dropping leaves in August in exhaustion, and so do many old trees, especially maples, in the woods around me. Water trees and shrubs deeply through hard frost, so that they enter dormancy well-hydrated. Evergreens (needled ones and broadleaf types like rhododendron) are particularly vulnerable to desiccation and winterburn otherwise.

DON’T PANIC IF EVERGREENS start to show some browning or yellowing of needles this month and next. The oldest, innermost needles typically shed after a few years. The details.

ALWAYS BE on the lookout for dead, damaged, diseased wood in trees and shrubs and prune them out as discovered. Ditto with suckers and water sprouts. No hard pruning now, though; too late to risk encouraging regrowth. No fertilizer this late, either.

houseplants

REST AMARYLLIS BULBS later this month by putting them in a dry, dark place where they will have no water at all for a couple of months. I put mine in a little-used closet.

IF HOUSEPLANTS NEED repotting, do it before they come inside later this month (less messy than in the house!). Don’t step up more than an inch (on small pots) or a couple (on large ones). Most plants don’t like to swim in their containers. Springtime’s fine for this, too, but I am often too busy then.

compost heap and mulch

DON’T LET THE HEAP dry out completely, or it will not “cook.” Turning it to aerate will also hasten decomposition, but things will rot eventually even if not turned. I extract more finished material and screen it each fall, to work into the gardens (and make more room for incoming fresh debris). How my expert friend Lee Reich makes amazing compost.

I USE BULK MULCH, which is cheaper than the packaged kind and also eliminates the waste of all those heavyweight plastic bags. Many local nurseries deliver. Top up mulch in all garden beds as they get cleaned up gradually. What good mulch is made of.

need help in other regions?

AGAIN: I’m in the Northeast, in Zone 5B, though the how-to in this story will work most anywhere (if timed slightly differently). For more Zone-specific advice, I’ve rounded up a new page of links to calendars and checklists from around the nation.