August Gardening To-Do List

Monthly Chores for Each Region

Harvesting rosemary
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In August, annual and vegetable gardens are winding down in the North. Some garden stands by the roadside in New England will already have pumpkins out for sale at the end of August.

Not so in the South, where there is plenty of gardening yet to go. Even in the North, the usual exit of the worst of summer's heat at the end of the month means an opportunity to take care of some tasks in the garden that you have been putting off. Find out what you should be doing in the garden in August, regardless of your region.

All Regions

  • Pick your spots to work outside. Anticipate heat waves and humidity, and get your work done on the days most pleasant for working outdoors.
  • No matter where you live, you will probably need to water the garden some in August.
  • Be on high alert for insect pests. These include but are not limited to thrips, tomato fruitworm, tomato hornworm, spider miteschinch bugs, scale, snails, and slugs.
  • The heat and humidity of mid-summer bring with them plant diseases. Inspect your plants for any diseased foliage now, remove it, and dispose of it properly (do not put it in the compost pile).
  • This is still prime time for heat-resistant flowers such as coleushibiscusMelampodiumPentas, plumbago, moss rose, and zinnias.
  • Keep up with your harvesting. Zucchini produce like crazy and get tough if left on the vine too long; share the excess with neighbors. Failure to harvest can also slow garden plants down.

Mid-Atlantic

There will likely be extended heat waves in August in the Mid-Atlantic. Protect your investment in your plants: Keep them adequately watered.

  • Keep an eye out for pests such as groundhogs and rabbits so that they do not get to your harvest before you do. If you find controlling these pests too difficult, consider growing groundhog-resistant plants and rabbit-resistant plants next year.
  • Keep those bargain-basement annuals (such as red salvia) you bought in July watered and insect-free so that they will be ready for use in fall plantings. They looked bad back when you bought them because they were root-bound and needed a trim, but you put the work in to revive them; protect the investment of time you put into them.
  • Continue to mulch to cut down on watering bills and to keep weeds at bay.
  • Ensure that your automatic irrigation system is working properly.
  • Harvest herbs both for immediate use and for drying.
  • Order spring bulbs.

Midwest

There will be scorching days in August in the Midwest and even extended heat waves. Protect your investment in your plants: Keep them adequately watered.

  • (Late August:) Sow peas for a fall crop.
  • Harvest vegetables and berries regularly.
  • Avoid pruning shrubs after mid-August. You will only be inviting new growth that will fail to harden off in time for cold weather and may become damaged.
  • Continue to mulch to cut down on watering bills and to keep weeds at bay.
  • Those bargain-basement annuals that you bought back in July should have returned to health by now. Keep them watered and insect-free so that, whenever the worst of summer's heat seems to have subsided, they will be ready for use in fall plantings.

Northeast

The Northeast sees hot, humid weather at the start of August. The second half of the month is unpredictable; sometimes it brings rainy periods.

  • Keep the annuals that you bought on the cheap in July (for use in fall plantings) properly watered and insect-free. You would not want to let them die now and lose the investment of time and energy you put into them.
  • Harvest vegetables and berries regularly so that the plants keep producing.
  • (Late August:) Sow peas for a fall crop.
  • Continue to mulch to cut down on watering bills and keep weeds at bay.
  • Avoid pruning shrubs after mid-August.

Pacific Northwest

As usual, the Pacific Northwest offers moderate temperatures in August. In Seattle, for example, the average high is 76 F and the average low 57 F; expect five days of rain.

  • Out with the old, in with the new: As the vegetables of early summer peter out, replace them with fall crops. This is the time to put in "cole crops," for example. These include broccoli, cabbage, Brussels sprouts, kale, and cauliflower. August is also a good time to plant leafy vegetables like lettuce and spinach. 
  • Prune Japanese maples lightly.
  • Fertilize summer-flowering bulbs such as dahlias, but stop fertilizing perennials, shrubs, and trees.
  • Water shrubs each week during periods when it does not rain much. Bud-set and berry-production alike are adversely affected by drought.
  • Plant autumn crocus corms (Colchicum).

Pacific Coast

August is sunny and dry in Northern California. The average high in San Francisco, for example, is 68 degrees F, the average low 57; you will get virtually no rain. Southern California is predictably warmer, with an average high of 84 degrees F, and an average low of 64 degrees F.

In Northern California:

In Southern California:

  • Continue to plan your fall garden.
  • Continue to mulch for weed prevention and water retention.
  • Water plants regularly.
  • After the harvest, fertilize your citrus trees.

Southwest

In the high desert, August is hot. In Santa Fe, New Mexico, for example, expect an average high of 83 degrees F and an average low of 53 degrees F; you will get about 10 days of rain. If Santa Fe is hot, then Phoenix, Arizona, is blistering, as summer is peaking. You will have an average high of 104 degrees F, an average low 82 degrees F, and hardly any rain.

  • Ensure that your automatic irrigation system is working properly.
  • Practice grasshopper control. There are organic insect soaps you can use to control these pests. Or, to save money but still stay natural, try a homemade concoction such as one part crushed garlic to every three parts water to make a spray you can apply wherever grasshoppers are a problem.
  • To prevent sunburn on young perennials and succulents, furnish them with some shade. This is easiest to do when you are growing them in containers (so that you can move the containers around as needed).

Southeast

It is quite hot in August in the Southeast. Atlanta, for example, has an average high of 88 degrees F and an average low of 71; this city will get 10 rainy days in August.

  • Watch for fungal disease, which is promoted by so much rain.
  • Continue to apply mulch as needed for moisture retention and weed suppression.
  • Start planning the fall vegetable garden.
  • After the harvest, fertilize your citrus trees.