Maine Home Garden News – September
In This Issue:
-
- September in the Maine Garden: The Month That Sets Up Everything Else
- Ask the Expert: How do I get rid of this pesky weed cloth in my perennial garden?
- Seasonal Sightings for September
- Featured Resource: Growing Fruit Trees in Maine
- Save Money and Beautify Your Garden by Overwintering Container Plants
- Maine Weather and Climate Overview
September in the Maine Garden: The Month That Sets Up Everything Else
By Sandra Mitchell, Penobscot County Master Gardener Volunteer, Maine Master Naturalist
There’s a particular quality to a Maine garden in September that’s hard to describe to someone who hasn’t experienced it. The light is different—lower, golden, arriving at a slant that makes even ordinary beds look beautiful. The air has that first-cool-morning smell. And underneath the still-generous harvests, you can feel the season beginning to turn.
For most gardeners, September is one of the most satisfying months to work, partly because the frantic energy of spring and midsummer has passed, the temperatures have cooled, the blackflies and mosquitoes have simmered, and partly because what you do now has long consequences. The choices you make in September—what you clean up, what you leave alone, what you plant, what you add to the soil—will quietly shape how next spring unfolds.
It’s a month worth taking seriously.
Harvest with a Different Eye
September harvests can feel almost embarrassingly generous. Tomatoes and zucchini are still coming (and coming, and coming), winter squash is sizing up, and the cool nights have reinvigorated the greens. September is definitely when I realize that I didn’t NEED a 6-pack each of 8 different tomato varieties, especially the cherry tomatoes which don’t easily can. And it IS the time I realize I need to stock up on more jars to store the tomato sauce, tomato juice, stewed tomatoes, raw pack tomatoes, hot pack tomatoes, crushed tomatoes, salsa, and yes—even the “tomato bits” (a real label from last season when I was overrun with tomatoes!). But this is also the month to shift your thinking from production to closure.
Pick tomatoes before cool, wet nights accelerate pathogens—don’t necessarily wait for every last one to ripen on the vine. Most will finish ripening nicely indoors in a warm spot stored in a paper bag. Harvest winter squash when the rind resists your fingernail and the vines are starting to die back naturally. Dig potatoes before soil temperatures drop. Keep cutting kale, chard, and mustard, but start thinking about your wind-down timing.
The September rule is simple: good enough and preserved beats perfect and lost. But also remember the master food preservers rule that only the best should be canned! Use your less-than-perfect harvest for immediate consumption to avoid wasting it, don’t cut the spots off and throw it in the canner.
Clean Up — But Not Too Much
The urge to reset beds completely at the end of the season is understandable but resist stripping everything to bare soil. Pull spent annuals, remove diseased tomato foliage promptly (it doesn’t belong in the compost), and clear out anything that’s genuinely done. But leave the stems. Leave some of the seed heads. Leave the leaf litter at the edges.
Many of the beneficial insects you spent all summer encouraging—native bees, predatory wasps, ground beetles—overwinter in hollow stems, leaf litter, and undisturbed soil. A garden that looks slightly untidy through the fall and winter months is often an ecologically healthier garden than one that’s been raked to perfection. I leave almost all of my plants in the soil over the winter and pull them in the spring when I wake up the garden, partly because I’m overwhelmed with canning all those tomatoes, and partly because I’m lazy. But I tell everyone that my garden looks like a disaster all winter long to benefit the pollinators!
September Is a Planting Month
This surprises some newer gardeners, but September may be the most underused planting window in Maine.
Garlic gets planted in October—soil is still warm, moisture is reliable, and it will establish roots before freeze-up. Buying your bulbs in September from your farmers market, mail order, or at the Common Ground Fair leaves you in a perfect timing window to get them in before winter really hits. Perennial herbs like thyme, oregano, and chives planted now will have a head start on next spring. Hardy perennials can be divided and transplanted with much less stress than in summer heat. And if you have empty beds, this is the moment to seed a cover crop—clover, winter rye, or hairy vetch will protect and feed your soil through the cold months. A word of caution on the vetch though – be sure you pull it out before it goes to seed or you will find it popping up everywhere for years. Trust me on that one. My laziness on weeding comes back to bite me with a generous vetch crop annually. Few things you do in September will pay off more visibly next May than a well-seeded, well-tended cover crop.
Feed the Soil
By September, the soil deserves your attention more than the plants do. Spread compost over empty beds. Use shredded leaves as mulch—they’re one of the best soil amendments available in Maine, and most of us have more than we know what to do with. I often don’t even shred mine in the fall, just layer them into the garden to be mixed in come spring when they have already started to break down. Avoid heavy tilling this time of year, which disrupts the fungal networks that are actively forming in fall soil. If you haven’t done a soil test recently, send one in now so you have results in hand before spring planting.
Think of September soil work as next year’s garden already beginning.
Pests Don’t Quit in September
Late summer pest pressure has a way of catching gardeners off guard. Aphids surge on fall brassicas. Imported cabbageworm can do real damage to kale and broccoli right through September. Slugs come back with a vengeance in the cool, damp nights. And as wild food sources shift, rodent activity near the garden tends to increase. Those cute chipmunks? Not so cute in September. And don’t even ask me about the amount of damage a single porcupine can wreck on squashes, and even tomatoes. Why do they like the small, tender zucchini and not the baseball bats?
Row cover on fall brassicas is worth the effort. Remove hiding places near vulnerable crops, and harvest promptly—a neglected pile of ripe squash is an open invitation.
Move Things While You Still Remember
September is the gardener’s editorial month. You still have a clear memory of what worked and what didn’t—which perennials got too big, which were in the wrong spot, which plant never looked right where you put it. Act on that knowledge now while it’s fresh. Divide overcrowded daylilies, hostas, and irises. Remember your gardening friends who would love getting your extras! Move plants that struggled in summer heat or shade. The combination of warm soil, increasing moisture, and your own still-vivid seasonal memory makes this the best possible time for those adjustments. Even planting things like fruit trees works amazingly well in September: they have enough time to establish before going dormant and will wake up happy in the spring.
If you don’t do it now, by February, you’ll have forgotten half of it.
Know Your Frost, But Don’t Fear It
In most of Maine, first frost can arrive anytime from late September onward. Keep frost cloth or old bedsheets accessible rather than buried in the barn. Covering tender plants for one or two cold nights can sometimes extend the season for weeks. Take note of your garden’s microclimates—the low spots that frost first, the south-facing wall that buys you an extra week. And remember that a light frost is not a catastrophe: kale, carrots, parsley, and Brussels sprouts actually improve in flavor after a touch of cold. Some crops are just getting good when the first frost hits. Know who is tender and will appreciate a blanket on those cold nights. When in doubt, put it out.
Just Walk Around
If there’s one thing worth building into your September routine, it’s this: spend time in the garden without a task in hand. Walk it in the morning when the light is good. Notice where water pooled, where the soil stayed dry, where the wind came through and flattened things. Pay attention to what thrived in spots you didn’t expect and what quietly failed despite your best efforts. These aren’t idle observations. They’re the foundation of next year’s decisions—and they’re only available to you right now, while the evidence is still in front of you.
A September Thought
The garden in September is still very much alive, but its energy is moving differently— downward into roots, into soil structure, into the quiet preparation that winter requires, and into the canning jars and freezers! The gardening you do this month is less visible than spring planting or summer harvesting, but it’s just as consequential. Don’t forget to expand your mental database this month as well—attend one or more of Maine’s wonderful agricultural fairs and see what others accomplished. No matter how much we know, someone else always knows more, has a different perspective, and has advice that is useable in your beds.
Gardeners who learn to take September seriously tend to have noticeably better springs. That’s not a coincidence.
Ask the Expert: How do I get rid of this pesky weed cloth in my perennial garden?
Answer by Jonathan Foster, Horticulturist, University of Maine Cooperative Extension
The University of Illinois Cooperative Extension has a great article on the disadvantages of landscape fabric that lays out (so to speak) the potential problems with landscape fabric. In short, it’s typically non-biodegradable (so it’s in your bed more or less for good once placed), the fabric’s permeability to air and water diminishes over time as it clogs with soil and organic matter, and it generally becomes tattered and inextricably twisted up in the roots of the plants you want to grow there and the weeds that work their way through. If you want to remove it in the future, it can be a dirty shredded mess that has to be pulled out in strips alongside a lot of plant material. I don’t mean to completely disregard the usefulness of landscape fabric—there are many situations where it’s a perfectly acceptable solution to a particular garden problem—but if these issues concern you, consider using cardboard or thick layers of old newspaper in its place. They will biodegrade over time, helping to build your soil, and will suppress weeds nicely until then.
As for getting rid of it, I’m afraid the gardener’s eternal one-two punch of patience and elbow grease are your best bet. After a couple of years in the soil, the cloth shreds, which makes it difficult to pull it out in one piece. You can try to get a spade or shovel under it and turn over the soil, but be careful so you don’t damage any perennial roots that have grown through it. Pull the fabric out whenever you see it and guard against its reentry into your garden from now on.
Pictured here is a 40′ × 40′ garden plot established in the late 1990s that once contained well-established perennials (some desirable, some not) planted in landscape fabric and covered with mulch. After years of struggling with invasive plants and weeds growing through the fabric, the desired perennials were dug out and the area was covered with a silage tarp for two growing seasons, which subsequently killed off all plant material in that area. After the tarp was removed, the landscape fabric was relatively easy to pull out and dispose of because the roots entangled in it had decomposed.
Landscape fabric can be a useful material in garden settings, such as this dahlia garden and pathways between garden beds.
Seasonal Sightings for September
By Maine Audubon Native Plants Program Coordinator Jocelyn LaClair. Photos courtesy of Maine Audubon.
Fall is a great time to appreciate black chokeberry (Aronia melanocarpa) and all the benefits it brings to wildlife. Black chokeberry is a small, multi-stemmed tree that reaches about 8 feet at maturity. It is tolerant of many different growing conditions and has a suckering habit that leads it to gradually form thickets. The leaves are rounded, finely toothed, glossy, and deep green, often with an orange or red leaf here and there. In autumn, the rest of the leaves will follow, turning bright orange or red before falling.
A key way to identify this tree is to look for very fine hairs along the midrib of the leaf although you may need a magnifying glass to do so! In the spring, black chokeberry has clusters of white flowers with five round petals each. The flowers have lovely pink anthers, and the flower buds are sometimes pink as well, all very attractive to pollinators. In late summer, the fruit ripens, turning deep purple to black. The berries are edible raw, but they are so astringent that they may make you pucker or “choke.” Undeterred by the tart taste, numerous songbird species and grouse will happily eat black chokeberries raw.
Other September signs of wildlife to look for include the following:
Snapping turtle eggs may be hatching now, depending on the weather. Earlier in the summer, female snapping turtles laid eggs in sandy or gravelly areas, often near roads or other human development. All the eggs hatch at approximately the same time, and the tiny turtles dig their way out and begin crawling to find a water body where they will spend the winter.
Now is usually when the fall warbler migration peaks though identifying them in their nonbreeding plumages can be a challenge! Look for these active birds wherever there is an abundance of insects: the canopy of native trees like oaks, pines, and maples; thickets of shrubs like viburnums and blackberries; or meadows of goldenrod. Migrating warblers will often stick around for a few days in areas with plenty of food (some eat fruits in the fall), so try to check areas where you’ve seen them on successive days.
Featured Resource: Growing Fruit Trees in Maine
If the bountiful tree fruits at the farmers’ markets and pick-your-own orchards have you thinking about adding an orchard to your landscape or giving your existing fruit trees a little more attention, our Growing Fruit Trees in Maine website is something you’ll want to bookmark for fireside research this winter.
This information hub features details about pollination requirements, planting, early care, site selection, common insects and diseases, winter care, and protecting trees from wildlife. It’s your one-stop shop for starting an orchard and keeping it productive and healthy.
Save Money and Beautify Your Garden by Overwintering Container Plants
Article and photos by Naomi Jacobs, Penobscot County Master Gardener Volunteer
My father was a frugal gardener, a child of the Depression and a descendant of Swiss Anabaptist farmers who disapproved of self-indulgence and knew how to stretch a dollar. He loved flowers but was reluctant to spend much at the nursery and would space his sixpacks of salvias and impatiens so far apart that the beds and windowboxes didn’t fill in until quite late in the summer.
My budget for new plants has always been more, well, “elastic” than his, but I inherited his tendency to balk at the price tags on those showy tender plants that look so tempting on display. It seemed wrong to spend as much for a plant that lasts only one season as for a perennial that returns year after year and provides endless free divisions once it’s established. $10 for a wee coleus or geranium in a 4 inch pot? $40 for a single fuschia or tuberous begonia in a hanging basket? No, thank you.
My attitude began to change once I learned to appreciate how much tender plants in large containers could contribute to my perennial garden. They provide long-lasting color throughout the garden, especially in areas with heavy shade and tree roots where only hostas will flourish. They fill the bare spots left after tulips, oriental lilies, daylilies, or lupines die back. They can be moved around to balance a color scheme—for example, a big white geranium or yellow begonia can be popped in to “lift” a planting where blue and purple shades predominate. But I still didn’t like the idea of buying new ones every year. So I began to experiment with overwintering container plants indoors, with the double benefit of saving money and preserving special varieties that might not be available another year.
Geraniums as Houseplants
My earliest attempts at overwintering were with geraniums. I lacked the patience to grow new plants from cuttings and wanted to foster something bigger than the classic windowsill plant. So I dug a few robust geraniums, planted them in 10-inch pots, and moved them into our unheated sunroom, where nighttime temperatures stay about 30 degrees Fahrenheit warmer than the outdoors. Once really cold nights arrived, the pots came into the kitchen for a few months, then returned to the sunroom until the last frost.
This has become a regular routine over the past 15 years or so. The geraniums bloom into December, take a pause, and then start up again. The dropped petals can be annoying, but otherwise they need little care beyond deadheading, and the fresh blooms are wonderful to have during the winter months. The oldest plants now occupy containers so big that it takes two people to move them outdoors in May. They really make an impact among the perennial plantings.
At a certain point I began to haunt the July and August clearance racks at the big box stores, looking for new varieties that could be grown to a larger size for future seasons. I now have a dozen different geraniums in more pots than the sunroom and kitchen can hold, so smaller pots have begun to fill tables near sunny windows in other rooms.
Storing Dormant Plants
Having succeeded with keeping geraniums alive as houseplants for multiple seasons, I wanted to try overwintering some other types of plants in a dormant state. I wasn’t sure it would work because most sources indicate that the ideal temperature is between 40 and 50 degrees, as in a heated garage that stays around 40 degrees. We don’t have a garage or a room that could be closed off to stay this cool. But I decided to take my chances in the unfinished basement of our 1890s house. Though there’s no direct heat, it maintains a winter temperature of around 60 degrees, due to heat from the boiler and from the earth below the frost line. The first attempt at overwintering dormant fuschias, dahlias, and mandevilla went well, and I intend to expand the effort this winter.
Dormancy is a sort of hibernation. Much like hardy plants after the ground freezes hard, or like a mama bear in her den, the tender plant shuts down its active processes. It needs no food and only enough moisture to keep the roots, tubers, or rhizomes from completely drying out.
Plants that can be overwintered in a dormant state include some of our most spectacular tender plants like fuschia, dahlia, canna, calla lilies, tuberous begonias, and mandevilla. Many such plants grown in containers can spend their dormant period in their original pots. Those with tubers or rhizomes can also be lifted and stored in a container filled with a dry bedding like wood shavings.
General Principles for Dormant Storage
Bring fuschia and mandevilla containers indoors when night temps drop below 50. Check them over for pests beforehand and manage accordingly.
For plants with rhizomes and tubers like dahlias, callas, cannas, and tuberous begonias, wait for the first frost to blacken the top growth. Cut back the stems and foliage to a few inches. Remove leaves that might harbor insects or disease.
If a plant is to be stored in its original container, scrape off the top layer of soil to remove any insect eggs or disease organisms. You might add a replacement layer of clean compost or soil.
If the plant is to be stored in another container, carefully lift the tuber or rhizome. Brush off the soil. Let it dry in the air for anywhere from a couple of days for dahlias to 4–7 days for cannas. Stow in a breathable container such as a cardboard box, paper bag, or open bucket, using light dry bedding like sawdust, wood shavings, vermiculite, perlite, or slightly dampened peat moss.
Store in a cool, dark, frost-free location: 40–50 degrees is ideal, but slightly warmer conditions can work too.
Do not fertilize; water sparingly if at all.
Check on the containers about once a month. Throw away anything that shows rot or mold. If a rhizome or tuber looks extremely dry or shriveled, give it a light misting. The bedding should not be damp.
In spring, pot up rhizomes and tubers and bring containers into indirect light. Fuschia and mandevilla could also be repotted at this time. When new growth appears, begin to fertilize lightly.
Be sure to harden off the plant before moving it outside after danger of frost.
Some Guidance on Specific Plants
Dahlias
Dahlias grow from tubers, which are thickened roots. They can survive quite well with complete neglect. I once left a couple of dahlia tubers in a bucket in a dark corner of the basement, intending to store them in sand, and forgot about them. Coming upon the bucket months later, I was amazed to see that one of them had sprouted new growth, though the other one had dried up completely. The following winter, I stored the survivor in light wood shavings purchased as hamster bedding, and it came through in great shape.
Dahlias can stay in their containers for dormant storage. Wait for the top growth to blacken with the first light frost, then cut back the main stems to 6 inches and move the container to its dark, cool winter home. Don’t fertilize and don’t water at all unless the soil seems extremely dry; just check on it occasionally.
You can also lift the tubers for storage in another container if you want to divide them, to save space, to make it easier to check on their health, or to avoid having to lug a heavy container down the basement stairs or out to the garage.
Again, wait for the first frost to blacken the foliage before gently removing the tuber from its pot. Cut the main stems back to 6 inches and brush off the soil. Let the tuber dry for a couple of days, before preparing it for storage. If putting multiple tubers in a single container, be sure to label the varieties, and be careful that they don’t touch each other. This will keep rot from spreading. Individual tubers can also be wrapped in plastic wrap to keep them from drying out or spreading disease. The plastic wrap approach takes up significantly less space and is used by many professional dahlia growers.
Calla lilies and canna lilies
Calla lilies and canna lilies grow from a rhizome, a thick underground stem. Like dahlias, they can spend the dormant period in an original container, or the rhizome can be lifted from the pot, cleaned, and dried before being stored in the usual way. Cannas like a longer drying period of 4–7 days.
Fuschias and mandevillas
These two popular plants can be either forced into dormancy or kept active as houseplants through the winter; the advantage of the dormant method is that they will need less attention.
The fuschia is actually a shrub; some varieties are hardy to Zone 8. For dormant storage, bring the plant inside before the first frost, checking carefully for pests and treating if needed; cut the stems back to 4-6 inches and remove all flowers and leaves; move the plant to a cool, dark place, and ignore it. About once a month, water sparingly. The plant will probably look as if it is dead, but when brought into indirect light in February or March, it will quickly sprout new growth. After new leaves appear, you can repot in fresh soil and begin to fertilize lightly. Be sure to harden off the plant before moving it outside. To overwinter fuschia as a houseplant, give it bright indirect light and sufficient humidity, and keep an eye open for spider mites, aphids and whiteflies.
Mandevilla is a vine. For dormant storage, prune back to 12 inches. Otherwise follow guidance for fuschias. You can expect the leaves to turn yellow and drop off. To overwinter as a houseplant, cut back the long stems by about half and give it bright sun. As with fuschia, watch for pests.
Begonias
Begonias are a bit complicated because the different types require different treatments for overwintering.
True tuberous begonias (Begonia × tuberhybrida) can be stored dormant in their pots, or the tubers can be lifted, dried, and stored following procedures similar to those for dahlias. Stop watering and feeding in early fall to let the foliage die back. Then cut back the dead leaves before preparing for storage. Repot/replant in the spring.
Rieger, wax, Rex, and cane begonias should be treated as houseplants. Bring the containers inside before nighttime temperatures drop below 50. They like bright indirect light. Don’t feed them in the winter months, and don’t over-water—let the soil dry out on top before watering again. Avoid getting water on the leaves, as this can foster disease.
Maine Weather and Climate Overview
By Sean Birkel, Assistant Extension Professor, Maine State Climatologist, Cooperative Extension, Climate Change Institute, University of Maine
Monthly Recap
Above normal temperature and only spotty rainfall in July and August has led to drought expansion across the majority of Maine. The statewide area rankings from the latest U.S. Drought Monitor are 32% abnormal dryness (D0), 52% moderate drought (D1), 9% severe drought (D2), and 7% no drought. The area of severe drought is focused across the Midcoast and Penobscot Bay regions, where the marine layer along the coast often inhibits convective rainfall. Impacts include low streamflows and lake levels, below or much below normal groundwater levels with reports of dry wells, increasing signs of moisture stress on perennial gardens and trees, and need for irrigation on agricultural crops. Additional information is available on the Maine Climate Office website.
Outlooks
September: Temperature and precipitation both have equal chances of being above or below normal.
Fall (Sep–Oct–Nov): Above normal temperature and equal chances of above or below normal precipitation.
The NOAA Climate Prediction Center reports that El Niño is strengthening with greater than 90% chance of a very strong event during fall and winter 2026/27. There is a 69% chance of this event exceeding the strength of previous El Niños since 1950. Warm ocean temperatures and moisture released into the atmosphere during El Niño tends to produce more weather extremes than usual. Maine winters tend to be warmer than normal during strong Niño events (for example: 1982/83, 1997/98, 2015/16, and 2023/24).
Maine Statewide 2026 Temperature & Precipitation Rankings
From NCEI Climate at a Glance
- Aug: Monthly summary not yet available
- Jul: 33rd Warmest (above average), 4th Driest (much below average)
- Jun: 12th Warmest (much above average), 35th Wettest (above average)
- May: 60th Coldest (near average), 29th Wettest (above average)
- Apr: 32nd Warmest (above average), 28th Wettest (above average)
- Mar: 34th Warmest (above average), 58th Driest (near average)
- Feb: 52nd Warmest (near average), 2nd Driest (much below average)
- Jan: 54th Warmest (near average), 28th Driest (below average)
- Spring (Mar–May): 30th Warmest (above average), 34th Wettest (above average)
- Winter (Dec–Feb): 60th Warmest (near average), 5th Driest (much below average)
For additional information, including historical temperature and precipitation data, weather forecasts, and seasonal climate outlooks, visit the Maine Climate Office website.
Do you appreciate the work we are doing?
Consider making a contribution to the Maine Master Gardener Development Fund. Your dollars will support and expand Master Gardener Volunteer community outreach across Maine.
Your feedback is important to us!
We appreciate your feedback and ideas for future Maine Home Garden News topics. We look forward to sharing new information and inspiration in future issues.
Subscribe to Maine Home Garden News
Let us know if you would like to be notified when new issues are posted. To receive e-mail notifications, click on the Subscribe button below.
University of Maine Cooperative Extension is an equal opportunity institution and provider committed to nondiscrimination. For more information, visit extension.umaine.edu/nondiscrimination.
University of Maine Cooperative Extension’s Maine Home Garden News is designed to equip home gardeners with practical, timely information.
For more information or questions, contact Kate Garland at katherine.garland@maine.edu or 1.800.287.1485 (in Maine).
Visit our Archives to see past issues.
Maine Home Garden News was created in response to a continued increase in requests for information on gardening and includes timely and seasonal tips, as well as research-based articles on all aspects of gardening. Articles are written by UMaine Extension specialists, educators, and horticulture professionals, as well as Master Gardener Volunteers from around Maine. The following staff and volunteer team take great care editing content, designing the web and email platforms, maintaining email lists, and getting hard copies mailed to those who don’t have access to the internet: Abby Zelz*, Barbara Harrity*, Kate Garland, Mary Michaud, Michelle Snowden, Naomi Jacobs*, Phoebe Call*, and Wendy Robertson.
*Master Gardener Volunteers
Information in this publication is provided purely for educational purposes. No responsibility is assumed for any problems associated with the use of products or services mentioned. No endorsement of products or companies is intended, nor is criticism of unnamed products or companies implied.
© 2023
Call 800.287.0274 (in Maine), or 207.581.3188, for information on publications and program offerings from University of Maine Cooperative Extension, or visit extension.umaine.edu.