September Tips

September...summer is winding down, but gardening chores begin to pick up.  What the avid gardener does in late summer and the beginning of fall determines how well next year's garden looks.  Time to get those hands dirty!

Indoor Plants

  • Do not use softened water on houseplants because the sodium accumulates in the soil and can kill the plants.
  • Make sure houseplants placed outdoors have plenty of water.  There are still many hot days left.
  • To avoid injury, bring in houseplants that have been outside for the summer before the temperature drops below 55 degrees F.  Make sure you check them for pests before bringing them in.
  • Take cuttings of begonias, geraniums, solenstemon (coleus), etc. to grow on as houseplants.
  • Do not wait for frost warnings to move your plants indoors.  Temperatures of 45 degrees F or lower can damage many tropical houseplants.
  • Feed your houseplants less frequently as the days get shorter.

Lawns and Landscaping

  • Over the next three months (Sept., Oct., Nov. or Dec.), it is time to apply your fertilizer for cool weather grasses.
  • Apply herbicides to your lawn for winter annual or perennial weeds in the fall.  Check herbicide labels before using, and select an appropriate chemical for the weed types and lawn type in your yard.
  • Don't allow leaves to accumulate on the lawn.  Rake them up regularly, and store in a pile or compost for use in your garden next spring and summer.
  • Dig new garden beds for next spring, incorporating organic matter, such as leaves.
  • Early autumn is the best time to sow grass seed.  By the time cold weather arrives, the grass is fairly well established and ready to grow and thicken early the following spring.
  • You can aerate your lawn in late September or October.  A garden fork works well for this.  Rake compost and sand into your lawn.
  • Feed lawns a last time with slow-acting fertilizer; if not already done.
  • Plant groundcover in September.  Flat or gently sloped areas are best.

Perennials, Annuals and Bulbs

  • Start taking cuttings of your annual plants to bring indoors and carry through the winter.  This includes geraniums, coleus, fuschia and begonias.  Be sure to place pots where they receive plenty of light.
  • Start selecting your favorite bulb varieties.  It is time to order your bulbs for planting in the fall.
  • If you are not sure which end of a bulb is the top, plant it on its side.  The stem will always grow upright.
  • When caladiums begin to lose their leaves, dig them up, allow them to dry, and store them in a warm, dry place.
  • To plant bulbs, loosen the soil and make a hole with a trowel or bulb planter.  Don't mash the bulb into the soil or you may damage the basal plate, causing it to rot.
  • Sowing seeds of hardy annuals, such as sweet alyssum, pinks, and sweet peas now will give the seedlings time to get established and develop good root systems before the coldest part of winter.
  • Establish new perennial flower beds; dig, divide, and replant overcrowded beds of cannas, daylilies, violets, and Shasta daisies.  Spread a liberal amount of organic matter and bulb fertilizer evenly over the area.  Mix this into the soil at least 6 to 8 inches deep.  Space divisions at least 1 foot apart in all directions so that root competition will not be a problem for several years.
  • Perennial phlox can be divided about every third or fourth year.  Divide big clumps of perennial phlox into thirds.  Early fall or early spring are the best times to plant or transplant them.
  • Divide lily-of-the-valley.
  • Allow plants to finish the summer growth cycle in a normal manner.  Never encourage growth with heavy applications of fertilizer or excessive pruning at this time.  Plants will delay their dormancy process that has already begun in anticipation of winter in the months ahead.  New growth can be injured by an early freeze.
  • Save seeds from favorite self-pollinating, non-hybrid flowers such as marigolds by allowing the flower heads to mature.  Lay seeds on newspaper and turn them often to dry.  Store the dry seeds in glass jars or envelopes in a cool, dry, dark place.
  • Marigolds, petunias and snapdragons will continue to bloom with regular food and watering.  Sprinkle the seeds from the dried pods for earlier blooms next year.
  • Dig up your begonias now and bring them indoors as a houseplant.  They will bloom all winter so you can use the cuttings outdoors next spring.
  • Continue to enjoy roses.  Fertilize them now for a longer blooming period.  Prune and untie rambler roses from supports.

Trees, Shrubs and Groundcovers

  • Give your perennials and woody ornamentals a fall check-up.  Look for weak or diseased plants.  Eliminate plants that might infect or take energy from neighboring plants.
  • ​Wait until deciduous trees and shrubs begin t drop their leaves before fertilizing them.  Roots are active until soil temperature drops below 40 degrees F, so nutrients will be taken up and used by the plants to develop a stronger root system.
  • Many balled and burlapped trees and shrubs are now sold wrapped in a synthetic burlap that will not rot in the ground, resulting in a rootbound plant that doesn't grow well if the burlap is left in place.  If in doubt, cut it away from the root ball once the plant is in place.
  • Tree-wound paint used after pruning are no longer recommended because they can slow healing and may promote decay.
  • Stake and wire newly planted trees only if necessary.  Use a piece of rubber hose around the guy wires to protect the trunk, and don't tie the tree tightly; it needs to be able to move a little in the wind.  Remember to remove the supports and stakes in a few months once the tree is established.
  • Do not move deciduous trees before their leaves fall.
  • Needle leaf or cone-bearing evergreens can be moved now if you transplant them.  Move plants with an ample root ball.
  • Add a 3-inch layer of an organic mulch around the base of plants to retain soil moisture and regulate soil temperature.  Keep mulch from direct contact with the trunk of trees.
  • If pesky seedlings of woody plants, such as elm, mulberry, hackberry or maple are found growing in your yard, remove them as soon as possible.  If left too long they will take over gardens and other landscape plantings.
  • Rake up leaves, twigs and fruit from crabapple trees and dispose of them in the trash to help control apple scab disease.


  • ​Pot up chives, parsley, and other herbs, and bring into the house to extend the growing season.
  • Plant garlic cloves.  Be sure to cover the garlic plot with a layer of organic mulch.
  • Herbs can be dried quickly in a microwave oven.  Place them between two paper towels, and heat for one minute.  Remove them from the oven, then test to see if the leaves are crisp.  If not, return them to the oven for a few more seconds.  Store in jars in a dark place so they will keep their color and flavor.
  • Hot peppers will keep best if stored after they are dry.  Thread the peppers on a string to dry.  Hang in a cool, dry place.
  • Pears should be picked at the hard ripe stage and allowed to finish ripening off the tree.  The base color of yellow pears should change from green to yellow as the fruit approaches maturity.
  • Be sure to keep strawberry beds weed free.  Every weed you pull now will help make weeding much easier next spring.
  • Asparagus and rhubarb can be planted from root divisions now.
  • Harvest parsnip, kale and Brussels sprouts as buttons become firm.
  • Take a 3 inch piece of copper wire and poke it right through the main stem of your tomato plants to save them from blight.
  • Protect potatoes from blight with protective covers.


  •  Making compost is good for your community.  Leaves, grass clippings, or prunings that go into the pile don't end up wasting space in a landfill.  Do this by incorporating some garden soil and a little fertilizer into the a pile of leaves, turning the pile every month or so for faster decomposition.
  • Sterilize old flower pots by soaking overnight in a solution of one part bleach to nine parts water.
  • Wood ashes contain phosphorous, potassium and calcium.  It can be placed on vegetable gardens and flower beds.
  • Fall is a good time for improving your garden soil.  Add manure, compost and leaves to increase the organic matter content.

September Garden Tips

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