August Chores

August Chores

By Karen Chang, U. C. Master Gardener

Spring brought cool, wet weather to Napa Valley this year, but we can always count on a hot, dry summer. In July, the valley experienced almost a straight week of scorching days. Temperatures up valley registered as high as 107ºF.

When the forecast is sizzling, plan to rise early and work during the cooler morning hours. Breakfast can wait until the sun is blazing, because there is a lot to do in the garden in August. We have to harvest, prepare for fall planting, keep a sharp eye on plants' water needs and be vigilant about fire safety.

Soil management

  • The combination of high temperatures and lack of water can stress plants, especially fruit trees. Some symptoms of heat stress are sunburn on the trunk and branches, branch dieback and the presence of bark beetles. Healthy trees are more resistant to beetle attacks.
  • Keep plant roots cool by mulching thickly around trees and shrubs, taking care to keep mulch away from trunks. An organic mulch will improve the soil as the mulch breaks down.
  • Monitor soil moisture and check your drip system for clogged sprinklers and emitters. If possible, water before the onset of a heat wave. For more information on water management, read "Water Management for Fruit Trees and Other Plants" and "Wise Watering of Landscapes," leaflets available from the University of California Cooperative Extension office in Napa. You can also read them here online. Click on "Healthy Garden Tips" in the column on the left. Alternatively, plan to attend a free workshop on water-wise gardening on August 29 or September 26. Contact the UCCE office at 707-253-4221 for details.
  • Prepare the soil for fall and winter vegetable seeds and seedlings. Remove all weeds before they flower to prevent reseeding. Dig in well-composted organic matter and wet the soil, then wait at least a week before planting.

Planting

  • Start seeds of bachelor button, calendula, columbine, fairy primrose, snapdragon, stock, viola and flowering cabbage and kale.
  • Sow seeds for sweet peas, California poppy and other wildflowers directly in the soil.
  • Keep color in the garden by setting out begonias, dahlias, marigolds, petunias and zinnias.
  • Sow these vegetable seeds directly in the soil: carrots, chard, lettuce, mustard, peas, radish, spinach and root vegetables. Keep the surface of the soil mist until the seedlings are established.
  • Start these seeds in containers: broccoli, cabbage, cauliflower, kohlrabi. Keep them in a shaded spot and water as necessary to keep the soil moist until the seedlings are large enough to plant out. This may take four to five weeks.
  • Plant new strawberry and artichoke plants for spring harvest.

Maintenance

  • When perennials have finished blooming, cut them back by about one third, or to a flush of basal growth, to promote repeat bloom. This practice is recommended for artemisia, coreopsis, lavender, penstemon, phlox, salvia, scabiosa and Shasta daisy, among other perennials.
  • Deadhead roses and flowering annuals to encourage continual blooming.
  • Fertilize azaleas, rhododendrons and camellias for the last time this year.
  • If your bearded iris blooms were sparse this year or the plants are more than four years old, now is the time to divide and replant them.
  • Fallen fruit can harbor pests. Pick up promptly and discard in the trash.
  • Water deep-rooted fruits and vegetables such as melons, squash and tomatoes so that the soil is moist to at least three feet.
  • Established shrubs and trees need a soaking now to prevent stress.

Harvest

  • You should be harvesting buckets of vegetables now: beets, beans, carrots, corn, cucumbers, eggplant, endive, lima beans, lettuce, melons, peas, peppers, potatoes, shallots, summer squash, Swiss chard, tomatoes. Harvest often to guarantee tender vegetables and to encourage plants to continue producing.
  • Harvest apples, figs, nectarine, peaches, pears, plums and early prunes as they ripen.