By Tim Joyce, KOIN Local 6 Environmental Reporter and OSU Master Gardener

September is the time of harvest. I try to eat out less—and make myself stay home to make delicious meals right out of the garden. There’s still summer heat to contend with—but the cool mornings upon us you can tell that change is in the air.

The average high temperature for Portland on September 1st is 78 degrees. By September 30th- the average high is 70. We also lose about 3-4 minutes of daylight every day this month—and by month’s end, we’ll have lost about an hour and a half of daylight. So, September is a time to enjoy the harvest and we can wait until next month to assess and re-assess the plan for next year.

This is the calendar from the Oregon State University Extension Service about what can/should be done in the month of May. It should be noted that OSU encourages research based sustainable gardening practices. Always identify and monitor problems before acting.

First consider cultural controls; then physical, biological, and chemical controls (which include insecticidal soaps, horticultural oils, botanical insecticides, organic and synthetic pesticides). And most paramount to this philosophy: always consider the least toxic approach first.
All recommendations in this calendar are not necessarily applicable to all areas of Oregon.

For more information, contact your local office of the OSU Extension Service.

 Apply parasitic nematodes to soil beneath rhododendrons and azaleas that show root weevil damage (notched leaves).
 Harvest winter squash when the "ground spot" changes from white to a cream or gold color.
 Plant lawns until October 15 in western Oregon.
 Plant or transplant woody ornamentals and mature herbaceous perennials.
 Plant garden cover crops as garden is harvested. Spread manure or compost over unplanted garden areas.
 Pick and store winter squash; mulch carrot, parsnip, and beet rows for winter harvesting.
 Spray holly for leaf and twig blight, blueberries for stem canker as needed.
 Reduce water on trees, shrubs, and vines east of Cascades to harden them off for winter.
 Plant daffodils, tulips, and crocus for spring bloom. Work calcium and phosphorus into the soil below the bulbs at planting time.
 Divide peonies and iris.
 Clean houseplants, check for insects, and repot if necessary; then bring them indoors.
 Protect tomatoes and/or pick green tomatoes and ripen indoors if frost threatens.
 Use stakes to support tall flowers and to keep them from blowing over in fall winds.
 Bait for slugs with traps or iron phosphate products that are safe for use around pets.
 Dig, clean, and store tuberous begonias if frost threatens.
 Harvest potatoes when the tops die down. Store them in a dark location.
 Prepare compost pile for recycling vegetation from garden and deciduous trees. Do not compost diseased or insect-infested plant material.
 Western Oregon: plant winter cover of annual rye or winter peas.
 Copper spray for peach and cherry trees.
 Monitor trailing berries for leaf and cane spot. Treat if necessary.
 Spray for juniper twig blight after pruning away dead and infected twigs.
 Monitor arborvitae for Berckmann's blight. Spray if necessary.
 Coastal and western valleys: spray potatoes and tomatoes for early and late blight.
 Willamette Valley: allow your lawn to dry out in late summer to make it less attractive to egg-laying crane flies.

Again, all recommendations in this calendar are not necessarily applicable to all areas of Oregon.

For more information, contact your local office of the OSU Extension Service.
To find the OSU extension service office nearest you, click on the following link: http://extension.oregonstate.edu/locations.php