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Gardener's checklist for summer

What to do in your garden in the summer

JUNE

Maintenance and Prevention

  • Check soil moisture and adjust the watering schedule on your irrigation controller accordingly. Water early in the day. Watch container plants, which may need daily watering.
  • Control powdery mildew, a fungus that likes dry summer conditions. Spray susceptible plants with a horticultural oil or biological fungicide.
  • Promote another bloom cycle of early-blooming perennials like Shasta daisies (Leucanthemum) and catmint (Nepeta) by cutting back spent stems or shearing old growth.
  • Clear dry brush and grasses to create a 30-foot fire-safe space around your home.
  • Protect fruit crops from birds with plastic bird netting or fabric row covers.
  • Use pot feet or boards to elevate containers sitting on hot pavement.

Feed & Fertilize

  • Fertilize roses and other summer-blooming plants. Use little or no fertilizer on herbs.
  • Make compost tea for a mild liquid fertilizer.

Propagation

  • Cut off spent flowers for continued bloom.
  • Sow seeds of basil, beans, beets, carrots, corn (early varieties), cucumbers, lettuce, summer and winter squash.
  • Transplant starts of broccoli, Brussels sprouts, eggplant, peppers and tomatoes.
  • Stake tall plants such as dahlias, gladiolus and lilies as needed.
  • Provide support for the vining stems of indeterminate tomato plants. Feed with a low-nitrogen fertilizer when fruit starts to develop. Do not overwater.
  • Harvest blooming lavender to dry for indoor use.

JULY

Maintenance

  • Monitor soil moisture. The water requirements of your plants peak in July. Established perennials, shrubs and trees need infrequent but deep watering. Container plants may need daily watering.
  • Drain standing water from saucers to eliminate mosquito breeding grounds.

Pests & Weeds

  • Control powdery mildew, a fungus that likes dry summer conditions. Spray susceptible plants with a horticultural oil or biological fungicide. Follow package directions. 
  • Pick up fallen fruit to discourage fungal growth and pests.
  • Monitor whiteflies — use sticky traps, thin out dense branches for air circulation, and use earth worm castings to discourage them. Using a reflective mulch or strips of foil will help repel them.
  • Check fuchsias for fuchsia mite. If found, cut back 6” from infected site.

Propagation

  • Pinch off spent flowers on perennials and annuals to encourage repeat bloom.
  • Pinch back chrysanthemums to encourage branching and increased bloom. Leggy impatiens and coleus also benefit from being pinched back.
  • Harvest vegetables promptly for continued production.
  • Cut spent berry canes to the ground. Fertilize new canes.
  • Dig up and divide overcrowded bearded irises. 
  • Dig up overcrowded bulbs after the foliage dies. Store in a cool, dry place for replanting in fall.
  • Sow seeds of summer and fall-blooming annual flowers directly in the ground. Cosmos, bachelor buttons, sunflowers, nasturtiums and zinnias are easy and fast to grow from seed. Keep the seed bed moist.
  • Sow seeds of beets, carrots, greens (collard, mustard, etc.), lettuce, summer and winter squash, and turnips.
  • Transplant starts of broccoli, Brussels sprouts, cabbage and cauliflower.
  • For indoor arrangements, cut flowers in the morning when they are freshest.

Feed & Fertilize

  • Feed azaleas, camellias and rhododendrons with a balanced fertilizer formulated for acid-loving plants.
  • Feed container plants.
  • Feed citrus.

AUGUST

Maintenance

  • Monitor soil moisture. Established perennials, shrubs and trees need infrequent but deep watering. Container plants may need daily watering.
  • Pick up fallen fruit to discourage fungal growth and pests.

Pests & Weeds

  • Monitor for spider mites by looking for fine webbing on plants. Minimize the chance of infestation by rinsing dust and dirt off leaves with a spray of water.
  • Manage yellow jackets by setting out traps. Follow package directions. 
  • Attach bands of corrugated cardboard around apple tree trunks to trap codling moth larvae.

Propagation

  • Pinch off spent flowers on perennials and annuals to encourage repeat bloom.
  • Prune hydrangeas after blooms fade.
  • Harvest vegetables promptly for continued production.
  • Transplant starts of broccoli, cauliflower and Chinese cabbage.
  • Sow seeds of beets, carrots, lettuce, peas, radish and turnips for fall harvest.
  • Order spring-blooming bulbs for best selection.

Feed & Fertilize

  • Feed azaleas, camellias and rhododendrons with a balanced fertilizer formulated for acid-loving plants.
  • Feed container plants.
  • Feed citrus.


Contributors: Faith Brown, UCCE Placer County Master Gardeners

Resource: Northern California Gardening: A Month-by-Month Guide by Katherine Grace Endicott