As Summer fades, we welcome the changes that September brings to our stores and in our gardens. Late-season Summer blooms and brilliant, fresh Fall colors are beginning to fill our benches, putting on a tremendous show. September is nothing short of exciting when it comes to gardening—after all, Fall is the very best time for planting! It’s also time to finish harvesting those tasty Summer veggies to make room for Fall and Winter crops.

September To Do List in the Garden

Seasonal Color

Add Fall color to the garden by planting Asters, Mums, Rudbeckia, Pansies, Ornamental Cabbage and Kale, or colorful Peppers to any blank areas in beds.

Refresh your Fall containers with plants that will pack a punch this season and continue to provide interest all Winter long.

Buy your Fall bulbs for Spring flowers now! We often sell out of the newest varieties and most popular colors of bulbs early, so stop by to snag them before they are gone!

  • Limited selections of Daffodils, Tulips, and Crocus have already arrived, and the full selection hits stores mid-September.
  • Bulbs can be planted as late as Thanksgiving, but late September or October is best for planting Spring-flowering bulbs.
  • Use G&B Soil Building Conditioner and bone meal or bulb food at planting time.
  • Fall bulbs also make great additions to perennial or evergreen Fall and Winter container plantings with annuals like pansies or violas layered over the top.
  • Check out our blog all about where and how to plant Fall Bulbs for Spring Flowers!


Divide and conquer your Spring-blooming, tuberous perennials: Dig up and split large patches of Iris, Peonies, Daylilies, Shasta Daisies and other perennials to reinvigorate the plants and make more to plant in other locations or give to friends.

  • Use a sharp shovel or cultivation fork to dig up the whole patch.
  • Use a pruning saw or Hori Hori knife to divide the clump, throwing away the corky center chunk and breaking the fresh growth at the edges into smaller pieces.
  • Replant with Malibu Compost and G&B Starter Fertilizer.

As weather cools and regular rains return, plant or transplant trees, shrubs, and perennials for a jump-start on Spring.

  • Use G&B Starter Fertilizer and Soil Conditioner when planting/transplanting.
  • Water in with Bonide Root & Grow or Malibu Bu’s Brew Compost Tea to help quickly establish a healthy root system and boost microbe levels in the soil.

Proactively control pests to improve garden productivity:

  • Control slugs now to reduce your garden’s breeding population. Use bait traps or non-toxic Sluggo, Sluggo Plus, or Bonide Slug Magic.
  • Apply beneficial nematodes to rhododendrons and azaleas suffering from root weevil damage which will look like notches/bites around the leaves; if unsure, bring a leaf sample to the garden center for diagnosis.

Edible Gardening

It’s harvest time!

  • Pick Winter Squash when area touching the ground changes from white to cream/gold in color.
  • Keep picking and eating Tomatoes—as plants slow down branches without blooms or fruit can be pruned off to keep plants tidy and productive.
  • Dig Potatoes, Onions, and Garlic when the tops die down; store in a cool, dark location.
  • Apply mulch to young plantings of Carrots, Parsnips, and Beets for winter harvesting; use G&B Soil Building Conditioner.

Continue to plant cover crops in the vegetable garden as larger bed space opens up. Cover crops are beneficial because they:

  • Compete with weeds
  • Improve the soil while growing
  • Add nutrition when turned under in early spring

Edibles to plant this month: Garlic (bulbs), Radish, Spinach, Kale, Chard, Lettuce, Mustard Greens


September Lawn Care

Start a new lawn or overseed patchy lawns now through mid-October.

  • Seed a new lawn with 7–10 lbs of seed per 1000 square feet; use half this amount if overseeding.
  • Use Grass seed, lime, G&B Organic Lawn Fertilizer, and G&B Soil Building Conditioner.

It’s also prime time to aerate and repair existing lawns.

If you have too much space to tackle on your own, our Residential Maintenance Enhancements team can come reseed and renovating existing lawns to set you up for success this Fall, Winter, and into next Spring.

Indoor Gardening in September

Houseplant care:

  • Bring houseplants indoors if they have been outside.
  • Develop a strong routine for Fall houseplant care by cleaning the foliage, checking for insects, misting, and watering.
  • Repot, and fertilize excessively root-bound plants if necessary. This is the last “active” growing month for indoor plants before they begin to go dormant for winter and the last chance for repotting this year.
  • Add some new grow lights—your indoor plants and your own mood will benefit!

If you have kept an amaryllis plant from last year:

  • Stop watering it now and allow it to go dormant for 4–6 weeks in a basement, shed, or garage.
  • Then, repot it and bring it back into a warm, bright room to re-bloom this winter.

What to Do for Fun in September

  • Lean into Fall decorating! Fancy pumpkins, gourds, and carving pumpkins arrive in stores mid-September. Combine orange and warty pumpkins with hay bales for a classic Fall vibe, or choose muted peaches and sage-green tones for a sophisticated Autumn update.
  • Attend a Fall Gardening class! Get tips on how to make the most of your Fall Containers, or learn about excellent trees for small spaces!
  • Take cuttings of herbs! Cut several 2 to 4-inch long stems from Rosemary, Basil, Thyme, and Sage—place in water for a few weeks indoors while new roots grow. Once small root mass has formed, gently transplant into container with G&B Potting Soil and place outside.
  • Take cuttings of Coleus! Cut an attractive 6-inch portion off the top of the plants and remove a few leaves from the base. Place the cutting in water and watch new roots form. Keep the plant in water through October for a science-y look and then pot up as a new Winter houseplant.

View the garden tips and checklist for October in the Garden. Or go back and view the tips and checklist for August in the Garden.

Pin It on Pinterest

Share This