Sara Swanson

September Gardening Advice 2017

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by Jennifer Fairfield

Editor’s Note: Manchester resident Jennifer Fairfield owns and operates the Garden Mill in Chelsea, serves on the Manchester Community Garden Committee, and volunteers with the school gardens at Klager and the MECC.

I can’t tell you how grateful I am for the rain we got this week! I have been dragging hoses and sprinklers around and filling up tree gators since June, because we have had almost no rain at all at my house. Chelsea has gotten some significant rain events this summer that just totally skipped past the Manchester area – where I live – and I am surprised I haven’t burned out my well pump with all of the watering I’ve had to do for my flower beds and veggie garden. I’m not sure that I’m happy with the significant drop in temperature, though! I personally like the cooler temps, but I’m not ready for my veggie garden to stop producing all the great summer vegetables I love eating. Of course, it is September in Michigan, so there’s a good chance we’ll be back up into the 80’s yet.

September is a great time for planting perennials, trees, and shrubs. Cool weather vegetables get a second season now, and if you want a nicer lawn in the spring, now is the time to work on that. In other words, September is a great month for gardening!

In the vegetable garden:

  • If you haven’t already, plant some leaf lettuce, spinach, and radishes now. You can extend your garden season a great deal with these plants – since they are quick to mature, they will be ready to pick before we get much frost. But speaking of frost, make sure you have row covers handy as we head into October. It’s also not unheard of for us to see a light frost or two before the end of the month, especially for those of us who live outside of town, and row covers can mean the difference between enjoying those last-minute veggies and losing them!
  • In Michigan, the best garlic gets planted in the fall for harvest the following summer. Our planting garlic is due to arrive in about a week. They can be planted any time up until the ground freezes, but are best planted after a few frosts. If you’ve never grown your own and are thinking about it this year, come talk to me – I’m happy to give you lots of tips garnered over the many years of growing my own. I also have the basics in a printed form to take home. I highly recommend giving it a try – it’s really quite easy and you get to try varieties you’ll never find in stores. In case you haven’t heard me say so, I LOVE home-grown garlic! I grow my own every year, and get cranky when I inevitably run out by mid- to late-winter and have to resort to grocery store garlic – it just isn’t anywhere near as good.
  • Pinch off any new flowers on tomatoes, peppers, and eggplants. Flowers that are forming now are not going to have time to mature before we get our first frosts, and leaving them on means that your plants are spending unnecessary energy on growing those, when they really should be using all their energy to mature and ripen the fruit that is already there. If you have very small fruits on these plants, you might want to remove those as well, as the much cooler temperatures will mean those aren’t going to mature very quickly, and may not get big enough to bother with before frost hits.
  • Pull any plants that have finished producing and compost them – but don’t compost diseased plants. Our winters are generally too cold for compost piles to get warm enough to kill off diseases, and if you use the compost in your garden, you risk contaminating your soil, and therefore next year’s plants.
  • You may find that, with the cooler temps, your summer squashes, cucumbers, and beans slow down production. This doesn’t necessarily mean they are done, but unless we get some significantly warmer temps, they will definitely not be providing as much.
  • Don’t stop spraying your tomatoes, cucumbers, and squash with fungicide. I’ve also been spraying my pole beans, as they came down with halo blight pretty early in the season. This is a disease that is usually in the seeds, so there wasn’t much I could have done to prevent it, and the only thing that can possibly help to extend the production is a copper fungicide. So, my beans have been getting sprayed with that all season. I haven’t gotten as many beans from my pole beans this year as I usually do because of the disease, but my bush beans made up for that! I will need to make sure I plant any variety of beans in a different part of the garden for a few years, to allow the disease to die out. Once a disease has been introduced to the soil, it will stick around for a few years – or longer, if you keep planting the crop in the same area. The disease needs that particular plant (or a relative) to thrive, so not planting the same thing in the same area for a few years will generally cause it to die off.
  • If you have basil in your garden, you might want to get it picked and used, or turned into pesto and frozen pretty soon. The nighttime temperatures have already dipped below 50 a few times at my house (including last night), and the predictions for tonight and next week show a number of nights in the 40s. Basil is a truly warm-weather plant, and really doesn’t like temperatures below 50 – it gets ugly black spots when that happens, which is actually tissue death. You can use row covers to help keep the temperature around your plants a few degrees warmer, but as we get further into the month, even that won’t help enough. You can dry basil, but it doesn’t freeze well, unless you make it into pesto first.
  • Most other herbs in your garden will last a while yet, but you can also pretty easily dry those any time, and freezing most herbs is also an option. To freeze, simply wash and dry them thoroughly, then chop and put into zipper bags, squeezing out all the air before putting them into the freezer.

Flowers, Trees & Shrubs:

  • September is a great time to plant new perennials, trees, and shrubs. Take advantage of the sales many garden centers have at this time of year, and get the plants in early so that they have time to get their roots established before cold weather sets in. Until the ground freezes, be sure that your new plants are getting plenty of water – either from Mother Nature or you – since the roots are not very good at taking water up from the soil until the plants get well established.
  • I’ve had a few people say that they noticed trees and shrubs starting to change color in early and mid-August. That seems early for a reason – because it is! It’s likely not because of the shorter days or cooler nights, but because of the stress they suffered from the lack of rain all summer. Leaves are the first to show signs of stress in plants, so if you are seeing something that doesn’t look right with the leaves of your trees or shrubs, don’t assume that it’s normal – try to determine the cause. One thing you can do if you aren’t sure what might be ailing your plants is to ask the Master Gardeners at Michigan State University Extension. You can give them a call, or use their online “ask an expert” tool to get answers to your questions. The one thing I would definitely do in the meantime is water, water, and water some more!
  • If your container plants are starting to fade, pull them out and replace them with fall plants, such as mums, asters (September’s official flower), and pansies. Mums are already in, and asters and pansies will be ready in about one to two weeks, according to our local growers. Ornamental cabbage and kale also make great fall displays, and will be ready about the same time as asters and pansies.
  • Fall planting bulbs will also be in soon. We have a great selection coming from Holland (the Netherlands, not Michigan) in the next week or two, and I can’t wait – I’m just in love with some of the new varieties of tulips, daffodils, and crocus! These all get planted in the fall, after we’ve had a couple of frosts, but before the ground is frozen. Don’t forget to add bone meal when planting bulbs, to encourage root growth. Bulbs can also be potted up and forced for early spring beauty in containers. We have information at the store on how to force all kinds of bulbs – just ask, and we can print it out or email it to you.
  • As it cools down, and perennials start to fade, it’s a great time to divide and transplant those that have outgrown their space or started to get thin at the center. I got a surprise in some native plants I bought last year – native sneezeweed that I didn’t intend to plant in one of my beds! It’s beautiful, but has a tendency to reseed like crazy, and is now trying to take over the entire bed. I also planted a gorgeous wild senna in the same bed, and then realized that it is just too big for the space, so it needs to be moved. Both of those tasks will be undertaken this month.
  • One way to be sure that you don’t end up with more of some plants than you want (such as my sneezeweed) is to deadhead them as soon as the flowers have begun to fade. Many flowering plants spread by dropping seeds from their spent flowers, so removing the flowers before that happens can keep them under control. This also goes for weeds. Cutting back the weed’s flowers before they go to seed will help to reduce the weeding you need to do next year. On the other hand, leaving some of the heads adds winter interest to your garden, and provides food to the birds. Life is full of little trade-offs!
  • If you put house plants outside for the summer, treat them with a pesticide meant for indoor plants before bringing them back inside. A few pests now can turn into an invasion in short order, and nobody wants that in their house!


  • September is a good month for revitalizing your lawn. You can fill in bare spots on the lawn by overseeding, The Lawn Institute has all the details on how-to.
  • De-thatching your lawn is also a good thing to do now. MSU has a good resource on this process.
  • Did your lawn get brown and crunchy while it was so dry? Has it started to green up with the recent rain? Are there patches that haven’t greened up? During the hottest, driest part of the summer, cool-season lawns, like those we grow in Michigan, naturally go dormant (unless given supplemental water). Once it starts to rain again, they should come out of dormancy and quickly get green again. If you have patches of lawn that are still brown when the rest of the lawn looks good, it’s possible that you have a pest problem. MSU Extension has tips on determining what the problem is and what to do about it.
  • If you only fertilize your lawn once per year, now is the time to do it, to encourage good root growth before winter. If you fertilize throughout the season, this will be your final application for the year.
  • Continue to mow, but mow a little higher – just not too high! The University of Minnesota Extension offers some easy-to-follow tips for lawn mowing to get the best results.


  • Some overwintering birds will use houses left out in the winter for shelter during cold nights, so consider leaving your bird houses out all winter. Clean out leftover nesting debris now to encourage them. Just be prepared to clean the houses out again in the late winter, before the nesting birds come looking for a new home in the spring.
  • Lots of birds are on the move, both coming here for the winter from further up north, and going south from here. If you haven’t been feeding all summer, start putting out food now to help them with their journey. They spend a lot of energy looking for things to eat in the wild, and that extra energy can make the difference in their ability to make it all the way to their winter home. For those sticking around, natural sources of food will start to dwindle, so what you provide can help them make it through the winter.
  • Also keep your birdbaths out, cleaned, and filled until we start to get freezing temperatures (or beyond, if your birdbath is freeze tolerant or you have a de-icer).
  • Leave hummingbird feeders out until well into October to help those guys make their long journey. Most of the hummers that have been visiting feeders around here all summer will be gone by mid-September, but others that spend the summer further north may still be making their way south as late as October, and will be grateful for the offering. Bring hummer feeders in at night if the temperature is predicted to fall below freezing.
  • Have you ever seen Chimney Swifts chattering and diving about in the evening? If not, you’re missing out on a great show – they’re a lot of fun to watch. Unfortunately, these beautiful birds have been in decline for years. Fortunately, Chelsea has a swift roosting spot at the old post office at the south-west corner of Main and South streets. Michigan Audubon is trying to get a better sense of the swift population in our state, and is encouraging citizen scientists to help with their efforts. Helping is easy and lots of fun for the whole family, and details are available on their website.

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