The Homeowners Column

The Homeowners Column

September Garden To Do List

Photo of Sandra Mason

Sandra Mason
State Master Gardener Coordinator

September means a second chance for gardeners to do all those things we didn't get around to in the spring. If you feel the urge to work in the garden but are not quite sure what to do, this reminder list should help. Now if the sight of this list makes you shudder, than you need to put down your pruners, sit down on that garden bench you never sit on and breathe in the last moments of summer. I have never met a gardener who had everything done on their "to do" list. Enjoy the process.


  • Transplant and divide most perennials.
  • This is the best time to divide peonies. Be sure to have 3-5 eyes per division. Replant so eyes are no more than 2 inches deep.
  • Replant areas with frost tolerant plants such as pansies and flowering kale.
  • Plant mums into well-drained areas. Planting on a slight mound may help to provide proper drainage to get mums through the winter.
  • Prepare houseplants for return trip indoors. Scout for insects. Thoroughly rinse leaves and container.
  • Begin 2-3 month dormancy for amaryllis. Do not water. Place in cool dark place. Dormancy begins once leaves yellow.
  • Purchase spring flowering bulbs for October planting.
  • Discontinue fertilizing roses.


  • Harvest herbs such as sage and oregano by hanging clean stems upside down in dark space.
  • Pot chives, oregano, basil or rosemary for winter use indoors.


  • Mow and water as necessary. Mowing height may be lowered to 2 inches as temperature decreases.
  • Fertilize in early September. This is the most important application of the year.
  • Reseed bare or thin areas with improved cultivars. Consider renting a slit seeder to get seed down into soil of existing lawns.
  • Reduce thatch if more then one half inch by using core aerifiers or vertical mowers.
  • Core aerifiers may be used to reduce soil compaction.
  • Establish turf by seed (best time). Prepare soil properly and get good seed to soil contact. Select turf mixes and blends appropriate to the site and to maintenance practices.Northern Illinois – August 15- September 7; Central Illinois – August 15 – September 15; Southern Illinois – Septemberer


  • Continue harvesting vegetables to keep plants productive.
  • Pumpkins and winter squash should have hard rind before picking, otherwise storage may be compromised.
  • Seed bare areas with winter rye or barley for a winter cover crop and to add organic matter to the soil.
  • Spinach and other leafy crops may still be planted for a fall crop.


  • Plant most trees and shrubs. Be sure not to plant too deep. Check for trunk flare. Attend November 8 program at Lake of the Woods on proper tree planting.
  • Water trees and shrubs. Plants, especially evergreens, should be well hydrated entering winter.
  • Avoid severe pruning now if possible. Wait until February or March for most trees and shrubs. Spring bloomers should be pruned right after bloom.
  • Pick bagworms from evergreens. Pesticide sprays are not effective at this time. Spray with Bt products next year mid-late June.


  • If you are planning to plant blueberries or rhododendrons, it is best to prepare the soil now for a spring planting. A soil test will indicate how much sulfur to add to lower the pH. Adding it now will give it time to react with the soil. Also add plenty of organic matter such as leaf compost.
  • Add plant debris to compost pile as you clean flower and vegetable areas. Debris will decompose faster if it is shredded or chopped. Also layer with soil or compost.
  • Add compost or shredded leaves to open areas in the garden.

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