July Garden Calendar

Have a few roses
How to Set Multiple Traps to Catch the Spotted Drosophila Fly

Produced by OSU Extension, each month provides reminders of key garden chores, such as fertilizing, pest control, planting, and maintenance.

Recommendations in this calendar are not necessarily applicable to all areas of Oregon. For more information, contact your local Extension office.

Sustainable gardening

The Oregon State University Extension Service encourages sustainable gardening practices.

Preventive pest management is emphasized over reactive pest control. Identify and monitor problems before acting and opt for the least toxic approach that will remedy the problem. The conservation of biological control agents (predators, parasitoids) should be favored over chemical controls.

Use chemical controls only when necessary and only after thoroughly reading the pesticide label. First consider cultural, then physical and biological controls. Choose the least-toxic options (insecticidal soaps, horticultural oils, botanical insecticides, and organic and synthetic pesticides — when used judiciously).

Maintenance and Clean Up

  • If a green lawn is desired, make sure lawn areas are receiving adequate water (approximately 0.5 to 1.5 inches per week from June through August). Deep watering less often is more effective than frequent shallow watering. Measure your water use by placing an empty tuna can where your irrigation water lands.

  • Mound soil up around base of potatoes. Gather and eat a few "new" potatoes from each hill, when plants begin to flower.

  • Early morning is the best time to water vegetable and flower gardens to reduce evaporation. Water the soil, rather than leaves to reduce disease. Water deeply and infrequently to encourage root growth.

  • Hanging baskets of flowers or vegetable plantings need careful attention to watering and feeding during extended periods of hot weather.

  • Weed and fertilize rhubarb and asparagus beds. A mulch of compost or rotted cow manure works well as fertilizer. Water deeply to develop crowns for next year.

  • Mulch to conserve soil moisture with paper, plastic, sawdust, etc.

  • Stake tall-growing flowering plants such as delphinium, hollyhocks, and lupine. Stake tomatoes, as necessary.

  • Make compost of lawn clippings and garden plants that are ready to be recycled. Do not use clippings if lawn has been treated with herbicide, including "weed-and-feed" products. Do not compost diseased plants unless you are using the "hot compost" method (120 degrees to 150 degrees Farenheit).

Planting/Propagation

  • Midsummer plantings of beets, bush beans, carrots, cauliflower, broccoli, lettuce, kale, and peas will provide fall and winter crops.

  • Dig spring bulbs when tops have died down; divide and store or replant.

  • Oregon Coast: First planting of Chinese cabbage, kohlrabi, and rutabagas.

Pest Monitoring and Management

  • Remove cankered limbs from fruit and nut trees for control of diseases such as apple anthracnose and bacterial canker of stone fruit. Sterilize tools before each new cut.

  • Control hollyhock rust by sanitation, picking affected leaves, or spraying with a registered fungicide. Read and follow label directions.

  • Watch for cutworm damage in garden. In July, climbing cutworms become a problem and large portions of foliage will begin to disappear on established plants. Use barriers, remove by hand, use beneficial nematodes when soil temperature is above 55 degrees Farenheit, or spray with Bt-k according to label directions.

  • Late July: Begin to monitor for early and late blight on tomatoes.

  • Place traps to catch adult apple maggot flies. You can use pheromone traps to monitor presence of pests.

  • July 10: Spray filbert trees for filbertworm, as necessary.

  • July 10-15: Spray peach and prune trees for peach tree borer, and peach twig borer, as necessary.

  • July 17-23: Third spray for codling moth in apple and pear trees, as necessary.

  • Cover blueberry bushes with netting to keep birds from eating the entire crop.

  • Watch for early and late blight on tomatoes. Correct by pruning for air circulation, picking off affected leaves, and/or treat with approved fungicide.

  • Monitor camellias, holly, and maple trees for scale insects. Treat if necessary.

  • Monitor rhododendrons for adult root weevils. Look for fresh evidence of feeding (notching). Try sticky trap products on plant trunks to trap adult weevils. Manage root weevils with beneficial nematodes (if soil temperature is above 55 degrees Farenheit). If root weevils are a consistent problem, consider removing plants and choosing resistant varieties (PDF).

  • Spider mites can become a problem on ornamental plants, vegetables, and fruit plants during hot, dry weather. Watch for dusty-looking foliage, loss of color, and presence of tiny mites. Wash infested areas with water or spray with appropriate pesticides.

  • East of the Cascades: If necessary, spray for corn earworm as silking begins. Protect bees from spray.

  • Continue monitoring raspberry, blackberry, blueberry, cherry and other plants that produce soft fruits and berries for Spotted Wing Drosophila (SWD). If SWD are present, use an integrated and least toxic approach to manage the pests.  Learn how to monitor for SWD flies and larval infestations in fruit.

  • Check leafy vegetables for caterpillars. Pick off caterpillars as they appear. Use Bt-k, if necessary.

Trade-name products and services are mentioned as illustrations only. This does not mean that the Oregon State University Extension Service endorses these products and services or intends to discriminate against products and services not mentioned.