To-Do List - September

by Karen Bodner, MG


Replace harvested crops with a last bunch of fall/winter crops such as arugula, mustard, or lettuce. Remember to transplant seedlings in the evening if days remain very hot. Water the hole before planting as well as after. Shade seedlings if possible for a day or two. Also sow overwintering carrots, corn salad, spring cabbage, radishes (last half of the month), and various greens. Remember that overwintering cauliflower needs to be sown before mid-month since it needs to put on at least nine inches of growth before the cold temps arrive so it can register vernalization and head up properly next spring.

Turnips and overwintering onions can be sown if done the first part of the month. Sow a fall or overwintering crop of peas and other legumes; inoculate to provide extra nitrogen-fixing bacteria in cooler fall soils. Transplant sprouting broccoli, collards, and fall cabbages. Shallots should be planted this month for an early summer harvest. Winter squash should be harvested late in the month when you can no longer pierce the shell with your thumbnail. If planting garlic, well-drained soil with lots of organic matter is important.

Flowers, perennials, and bulbs

Keep on deadheading to encourage continued blooming and minimize disease problems. Also remove dead and diseased leaves. Taller stems on plants such as monarda and Shasta daisy can be cut back after flowering by one-half to one-third to a lower growth point for regrowth. If sowing hardy flowers now, rake in lightly and water; some will germinate immediately and overwinter, and those that require vernalization will just wait for spring.

Early in the month fertilize annuals and water well. Pot up houseplants or other cherished "tenders" to acclimate them to an inside or drier location, or take cuttings at this time.

It's a great month for planting perennials. Dig up and divide overgrown clumps of perennials, iris, and spring-flowering bulbs such as daffodils and tulips. Nurseries will soon offer spring-flowering bulbs to plant. Dig up, dry, and dust gladiolus bulbs. Phoebe says you will get a much better plant next year and it prevents overcrowding. If you are not digging them, be sure to provide a nice loose mulch (I like straw or leaves) for the winter. Remove and store begonias indoors.

Vegetative Propagation: Last chance to take cuttings such as geraniums, tender herbs, impatiens, and so forth for your indoor winter garden. Continue to sow hardy perennials in pots to overwinter in a cold frame or greenhouse; again, some will come up, and some won't germinate until next year. Semi-mature cuttings can still be taken from Artemesia and fuchsia in addition to Helichrysum, Hyssop, Iberis, Penstemon, Polygonum, and Salvia. Hardwood cuttings from Lavandula and Lavatera are okay this month. Cut back, clip, and shape semi-woody perennial herbs such as lavender, Teucrium (germander), thyme, and Santolina.

Trees and shrubs

Give one last good soaking to prepare these guys for winter; then start reducing water to harden them off. It's a great month for planting or transplanting trees and shrubs. Remember the planting tip from last month for preparing the hole. Prune dead wood from shrubs at this time. Arborvitae should be sprayed this month for blight.

Vegetative Propagation: Take semi-mature cuttings from several trees and shrubs: Enkianthus, Hebe, Hydrangea, Holodiscus, and Santolina to name a few. Hardwood cuttings can be taken from Ilex and Kalmia.

Pruning: Betula are pruned when dormant, from late summer up to midwinter. Ilex and Acer are pruned now to remove reverted shoots. Formal evergreen hedges should also be clipped at this time.

Fruits and nuts

When cutting your caneberries back, cut as closely to the ground as possible and inspect for hollow stems which are evidence of a borer. Spray peach and cherry trees as well as trailing berries with copper. It's time to harvest apples, pears, walnuts, chestnuts, and other nuts. The MFPs have lots of literature on harvesting and storing these fruits.

General gardening

Overseed, repair, or sow new lawns this month and next. On established lawns apply a complete lawn fertilizer between now and mid-October. Sow cover crops this month on unplanted beds, or apply several inches of compost or manure. If you want crimson clover, September is the best month to sow, certainly before October 15. Work in manure if it is fresh; add lime if necessary (at least every three to four years), and have soil tests performed. Mulch around your semi-hardy plants.


If necessary, continue to spray tomatoes with copper or other fungicide for blight. Look for the imported cabbage worm (often along the stalk), and hand pick larvae from your brassicas. Cabbage maggot, corn earworm, and cucumber beetles are in most stages, and those lovely slugs resume their egg-laying ways. The carrot rust fly adult is also still out. Look for larvae of cutworms and cabbage looper pupae as you work soil. Filbertworm pupae can be found in silken cocoons in soil and under leaves or trash. Of course all of our beneficial warrior friends are still active in most stages too, so keep an eye out for their eggs. Green lacewing eggs are often found on flower stalks and blades, so inspect them before deadheading and removing spent plants.

A =Adult E =Egg P =Pupa
L =Larva   N =Nymph
Beneficials are italicized Underlined stage = extended season OG=overlapping generations


rove beetles-A/N
western damsel bug-A/E/N (OG)
big-eyed bug-A/E/N (OG)
butterfly caterpillars-A/L
minute pirate bug-A/E/N (OG)
green lacewing-A/E/L/P (OG)
syrphid fly-A/P/L/E
tachinid parasite-A/E/L/P
wasp parasite-A/E/L/P (OG)
predator mite-A/E/N (OG)
cinnabar moth-P
honey bees-A/E/L/P (OG)
alfalfa leafcutting bee-A/E/L/P
predatory nematodes-Infective Juveniles/A

aphids-A/N (OG)
onion thrips-A/N (OG)
beet leafhopper-A/N (OG)
carrot rust fly-A/E/L/P
symphyllans-A/E/N (many OG)
green peach aphid-A/N (OG)
wireworm beetle-A/L (2-3 YRS)
cucumber beetle-A/L/P
asparagus beetle-A/L/P
variegated cutworm-A/E/L
western cherry fruit fly-P
apple aphids-A/N (OG)
codling moth-A/E/L
corn earworm-A/L/P (OG)
imported cabbageworm-E/L/P (OG)
cabbage looper (nocturnal adult)-P
cabbage maggot-L/P (OG)
cabbage aphid-A/N (OG)
cabbage flea L/P
pear psylla-N
peachtree borer-E/L
peach twig borer-A/E/L
root weevil-A/E/L
spider mites-A/E/N (many OG)
pea weevil-A
greenhouse whiteflies-A/E/N
elm leaf beetle-A/P
bark beetle-A/L/P
white grubs-A/L(2 yrs)
bean aphids-A/N (OG)
stink bugs-A/E/N (OG)
pea aphid-A/N (OG)
western flower thrips-A/E/N (OG)
onion maggots-P
filbert leafroller-E
raspberry crown borer-A/E/L(2 yrs)P
strawberry and currant aphid-A/N (OG)
holly and soft scale-N
rose leafhopper-A/N
grasshopper-A/E (OG)
strawberry crown moth-L
western raspberry fruitworm-A
walnut husk fly-A/E/L
sod webworm-E/L
fall webworm-L/P
boxelder bug-A/N
seedcorn maggot-P
western potato flea beetle-A/E/L/P
spinach and fruit leafminer-A/L/P (OG)
apple maggot-L/P


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