September Garden Tasks

The start of the Calendar year may be January but to me it has always felt like September. Maybe it was the remnants of feelings of going back to school. But I think those feelings have been reinforced over the years through gardening. Fall is a time to reap the rewards of your garden and to take stock and prepare for next year. The two faced god Janus (who January is named after) would be right at home looking back over the last season and anticipating and making plans for next season. So embrace this active time of the year in the garden and enjoy the changes – the leaves turning, the maritime layer dominating the morning weather, the subtle changes in the smell of the woods and the joy of sharing this grand time of the year with others at fall festivals and fairs.

Flower Garden

  • Bulbs ordered last month will begin to arrive and you can plant them as soon as the soil is ready. It’s still not to late to get an order in for bulbs.
  • Transplant perennials that were sown in late summer e.g. delphiniums, forget me not, primroses.
  • Divide astillbes, daylilies, lily of the valley, peonies, phlox, Shasta daisies, Siberian iris, and violets.
  • Take cuttings of overgrown tender plants like impatiens and geraniums etc to bring indoors for the winter.
  • Root prune recalcitrant Wisteria. If your maturing wisteria has failed to bloom make vertical cuts with spade about 10 inches away from the trunk outlining a circle. If its trunk is thicker than 1″ add 10 inches to the distance for every additional inch of trunk. Then fertilize with a high phosphorus fertilizer like rock phosphate or bone meal.
  • Stop deadheading roses and allow hips to form. This helps roses slow down and prepare for dormancy.
  • Keep deadheading annual flowers and other perennials to maintain bloom till frost.
  • Remove old flowers from late blooming subshrubs like heaths and heathers.
  • Keep cultivating as weeds pick up with increased rainfall and cooler weather. Many weeds will overwinter but it they are easier to control now while they are small.

General Landscaping

  • This is an optimal time start a new lawn from seed or seed worn or bare spots as well as lay sod.
  • You can lower mowing height now down to 1.5 inches.
  • September is a good time for a late lawn feeding and pH correction.
  • Send out soil for testing to determine what soil amendments to add next month when preparing the beds for winter or for your fall lawn feeding. A nearby lab is based in Portland: A&L Western Agricultural Labs
  • It’s fall planting time! Take advantage of the warm soil and increase in rainfall. You can plant perennials, shrubs and trees. This is a good time to start a new garden or expand beds.
  • Keep the compost turned as you add debris from cleaning up the garden and mowing the lawn.
  • Take stock – Make a list of successes and failures in this year’s garden to use for next years plans.

Indoor Garden

  • Prepare greenhouse for cooler weather. Clean up used pots, benches and growing surfaces with 10% bleach solution. Check for leaks and cracks and repair. Test heating and ventilation systems and repair if necessary (as Poor Richard AKA B.F. used to say “an ounce of prevention”)
  • Prepare your indoor plants that have been outside for the summer to come back inside. No frost but many don’t like night temps lower than 45-50. Hose off leaves, and inspect/spray for insects.
  • Beat the shopping malls and advertisers and think about the holidays now: Start treatment of poinsettias (16 hours uninterupted darkness) so they bloom in December. Start kalanchoes, ornamental peppers from seed now. Put Christmas cactus in cool dark location to form flower buds. Pot up paper white narcissus every two weeks. The first batch should come for mid-December. Looking way ahead – pot up Easter lily bulbs
  • Withhold water from Amaryllis bulbs and give them a rest (dormancy). Leave them for at least a month before watering and breaking dormancy.

Pest Alert

  • Insect Alert
    Since there are no killing frosts in September most of the warm season insects mentioned in past calendars should still be watched for and controlled including aphids, whiteflies. Most other insects will begin to prepare to overwinter. If you can stop insect pests from reaching their winter destination you can get very good control. For example keeping apple maggot infested fruit from sitting on the soil will prevent them from leaving the fruit and heading underground. Slugs make a comeback in cooler weather and have a second smaller breeding season so keep the iron phosphate based slug baits at the ready.
  • Diseases alert
    You can help control all fungal diseases by removing falling leaves and fruit from plants that have shown sings of disease (e.g. Anthracnose on Dogwoods). Late blight is the new addition to the fungal diseases that we have seen throughout the summer. Late blight attacks tomatoes and potatoes. The symptoms are black lesions on leaves and fruit. Keep the leaves dry to help prevent this disease. Apply a copper-based fungicide at first sign of disease.

Vegetables, Herbs & Fruit

  • Plant from seed lettuce, radishes and other cool weather greens
  • Sow Overwintering vegetables. This will gives you a head start next spring providing the earliest possible harvest. Carrot (Overwintering type only like Merida otherwise they will bolt come spring), Fava beans, Spinach (e.g. Giant Winter), Lettuce (Winter Marvel) and snow peas.
  • Harvest Brussels sprouts, collard greens, kale, peppers, pumpkins and winter squash (cut off and leave stem otherwise rot will get into top), Squash, tomato, celery (blanch stalks with boards) and potatoes that will be eaten now and not stored.
  • Pick Apples as they turn color (turn of the wrist should remove the fruit easily), Asian pears as apples but European pears are picked firm and ripened indoors in a dark spot. Pick figs as they soften and turn downards and grapes as they sweeten.
  • Move strawberry runners so new plantlets are in appropriate space or pin into a pot and grow in container until it can be transplanted in a new location.
  • Order or buy garlic for planting this and next month.
  • Root woody herbs to grow on a windowsill like rosemary or and sage.