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10 Things to do in a September Garden

Michele MacKinnon

September gardens are grief and glory rolled into one last hurrah
before the autumn winds blow in. ~ Layla Morgan Wilde

  1. Take cuttings from annuals to overwinter them. Use a sharp knife or pruning shears to cut just below a set of leaves. Strip off the bottom couple sets of leaves, pot in good quality potting soil, and keep the soil evenly moist. After a week or two, resistance to a gentle tug indicates cuttings have rooted. 

  2.  Cut dahlias often to keep them blooming. Stake top heavy plants to support stems. There is no need to fertilize after flowering has begun. ​

  3. Refresh containers. Replace spent annuals with flowering kale, mums, fall grasses or ornamental peppers.  ​

  4. Overrun with tomatoes? Try this simple recipe and enjoy the taste of summer all year long in tomato sauces, soups, or slather over goat cheese on toasted bread. Yum!  

  5. Plant more veggies. Really. It’s the perfect time to start lettuce, Asian greens, kale and spinach. As temperatures drop, protect seedlings with a floating row cover or an old sheet. Enjoy fresh greens all winter when grown in a cold frame.  

  6. Cut off spent annuals and vegetables, and compost them. Pulling plants exposes weed seeds so avoid this when possible. Discard diseased plant material.  

  7. Weed, weed, weed. Collect and dispose of all seed heads. As long as weeds are seed-free, allow them to dry and compost them to capture nutrients in their tissues. Annual weeds (crabgrass, lambs quarters) die after setting seed so if time is limited, focus efforts elsewhere. Control biennial weeds (burdock, garlic mustard, mullein) by pulling. Insert an old bread knife deeply along the side of tough or deep roots and twist, or cut around the root mass and pull. This usually gets enough of the root to prevent regrowth. Perennial weeds (dandelions, plantain, ground ivy) develop strong root systems to ensure ongoing survival. When digging isn’t a practical option, starve roots with repeated cutting. Time the final cutting of tough woody roots in late summer or early fall, before leaf drop. This stops nutrients in leaves being sent down into the roots for winter storage. Weeds with runners, like ground ivy, require elimination of the entire root system.

  8. Keep hummingbird feeders filled so these avian acrobats can fuel up for migration. Make nectar with a 4 parts water, 1 part sugar ratio. Skip the red food dye.

  9. Don’t panic if fall webworm appears on trees or shrubs. While the ickiness factor is high, long-term damage is low. Cut off the affected branch, bag it and put it in the trash. Recheck plants for recurring outbreaks.

  10. Order spring bulbs before popular choices are sold out. Force bulbs in attractive containers to brighten winter days. Plant an assortment of containers to grace front doors with a cheerful display next spring. Learn more on growing showy amaryllis bulbs in my previous article, Winter’s Flowering Diva - The Amaryllis. One of these potted beauties makes a great gift. 

Ed. note: Sierra Club Connecticut does not encourage the use of pesticides - try Michele’s recommended non-toxic methods instead. 


Michele MacKinnon is a UCONN-Certified Advanced Master Gardener, garden educator and speaker, and Sierra Club member.


To contact Michele MacKinnon, email


Photo credit: Michele MacKinnon

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