The Vegetable Garden In August

  • By Cleve Campbell
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  • August 2016-Vol.2 No.8
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  • 1 Comment

“The month of August is a busy month in the vegetable garden.” This must be about the fifth month in a row that “The Monthly Tips and Tasks” article has begun with that sentence.  Perhaps you’re beginning to believe that every month in the vegetable garden is a busy month.  Me,too.  Well, let’s begin with the short version of the August to-do list: continue harvesting vegetables, continue removing spent spring and summer crops, plant fall crops and cover crops, and, of course, continue weeding.

Speaking of weeds, I am always amazed at how they continue to pop up week after week and year after year. I am often asked: where do they come from and why so many? They can be blown in by the wind, washed in by surface water, and introduced by birds and other wildlife.  And the weed inventory can also be increased with the application of organic mater: compost and manure. One of my biggest gardening surprises was the day I learned that the majority of weeds come from seeds we gardeners plant ourselves. Whoa, hold on! Gardeners plant weeds? You bet, every time a weed is allowed to go to seed, they replant themselves in our garden. Okay, by now you are thinking it’s August, it’s hot and I got sweaty just walking to the garden! How are a few weeds going to seed in the garden going to make a difference? Well, you are going to be surprised!

A garden friend once remarked, “Certain weeds have mastered every survival skill except learning to grow in straight rows! And it’s as if they are the home team; they always win because they bat last.” One of the survival skills that weeds have truly mastered is their ability to produce an abundant seed crop. How abundant you ask? Well, many common weeds have the ability to produce thousands of seeds that are deposited on the earth, and these seeds can remain fertile for up to 40 years or more  after they are added to the weed “seed bank.” A seed bank is simply the collection of weed seeds in the soil. Let’s look a little closer at that seed bank.

A single weed plant can produce  a great number of seeds.  Examples of individual plants that produce a hefty number of seeds include: red pigweed (Amaranthus retroflexus —  117,000 seeds per plant), common purslane (Portulaca oleracea — 52,000 seeds per plant), shepherd’s purse (Capsella bursa-pastoris — 38,000), common lambsquarters (Chenopodium album — 28,000) and yellow foxtail (Setaria glauca — 12,000).

In addition to producing vast quantities of seeds for germination, weed seeds have a protective coating and have the ability to lay dormant in the soil   up to 40 years or more  and still remain viable for germination.

This annual collection of seeds, if present in the garden or seed bank, makes weeds a tough adversary. It is estimated that the seed bank can be depleted by 80-90 percent within 2-3 year period of control. However, the seed bank can be replenished with a single year of bad control. Did you ever wonder about the origin of  that old gardening proverb, “One year of seeding makes seven years of weeding”? Think of that weed seed bank in the garden waiting to sprout! So getting those weeds out of the garden before they produce seeds can make a big difference in reducing the number of weeds in years to come.

Common Purslane (Portulaca oleracea) a single plant can produce up to 52,000 seeds. Photo Source: Oregon State University

Common Purslane (Portulaca oleracea). A single plant can produce up to 52,000 seeds.
Photo: Oregon State University

Red Pigweed (Amaranthus retroflexus) a single plant can produce up to 117,000 seeds. Photo Source:

Red Pigweed (Amaranthus retroflexus).  A single plant can produce up to 117,000 seeds.

August is a transition monththe vegetable garden is moving from late spring and summer crops to cool weather or fall crops. The gardener who fails to plant a fall garden is often missing out on a remarkable growing season. Here in central Virginia, we can harvest fresh produce well into the fall and often into early winter. No matter how ragged the summer garden looks, a fall garden offers us not only a second growing season, but also a second chance to plant those early spring crops that failed in the summer heat. August in central Virginia is fall planting season —  the time to plan and plant a fall garden. Timely planting is the key to a successful fall garden.

The following planting chart was created by using the Virginia Cooperative Extension Publication No. 426-334, “Fall Vegetable Gardening.”


August 1-10 August 11-20 August 21-31
Brussels Sprouts*
Broccoli* Broccoli*
Cabbage* Cabbage*
Cauliflower* Cauliflower*
Chard, Swiss Chard, Swiss
Collards Collards
Cucumbers Cucumbers
Chinese Cabbage* Chinese Cabbage*
Endive Endive
Kale Kale Kale
Kohlrabi Kohlrabi Kohlrabi
Lettuce, bibb Lettuce, bibb Lettuce, bibb
Lettuce, leaf Lettuce, leaf Lettuce, leaf
Mustard Mustard Mustard
Peas, Garden Peas, Garden
Radish Radish
Rutabaga Rutabaga
Spinach Spinach Spinach
Turnips Turnips Turnips
Cover Crops:
Buckwheat Buckwheat Buckwheat
* Denotes Transplants
The suggested dates may vary for different areas.


More Gardening Tips and Tasks For August:

  • When choosing vegetables for the fall garden, select those that are semi-hardy, as they will tolerate a light to moderate frost, and look for those with quick maturity (fewest days to harvest).   This information will be listed on the seed packet or in the seed catalog.
  • Vegetables that can be planted in August include leafy greens such as lettuce, spinach, collards, kale and mustard. Radishes, turnips, beets and carrots can all be started from seeds in August. Chinese cabbage, broccoli, cauliflower and brussel sprouts can be transplanted in August and still have enough time to produce a good harvest. When selecting plants for transplanting at the local gardening center, be sure you are selecting edible (not ornamental) varieties of cabbage and kale.
  • Fall plants often have fewer insect problems, as they avoid the peak insect activity period of midsummer.  However, some insects, such as cabbageworm and corn earworm, may be worse late in the year than in the summer; vigilance is still required. Avoid some pests and diseases by planting crops of different families than were originally in that section of garden.
  • When planting fall crops, prepare the soil by restoring the nutrients removed by spring and summer crops. A light layer of compost, or a small application of an organic or complete fertilizer will provide the nutrients needed by your fall crops.
  • Dry soil can making working the soil difficult and can also inhibit seed germination during the late summer. Plant fall vegetables when the soil is moist — after a rain or after you’ve watered the area thoroughly the day before planting. Plant the seeds slightly deeper than recommended for spring planting. Once planted, water them in thoroughly, and then use mulch or a covering of compost to prevent the soil from crusting.
  • Watering properly is the key to conserving water in the heat of the late summer. One inch per week applied all at one time will wet the soil 6 to 8 inches deep and insure good yield from your mature crops. Two inches of organic mulch such as leaves or straw will cool the soil and reduce surface evaporation of water. Water the garden early in the day so the foliage dries before nightfall. Wet foliage at night increases susceptibility to fungus diseases.
  • When mulching around young seedlings, care should be taken not to cover the seedlings.  Young seedlings need as much sunlight as possible, and the mulch should be covering the soil — not engulfing the young plants.
  • Pick summer squash and zucchini every day or two to keep the plants producing. If you are going on vacation this month, harvest all your vegetables beforehand, and then arrange for someone to pick fast-maturing crops such as squash and okra while you’re off loafing.  Otherwise, your vegetables will become over-mature and stop producing,
  • Potatoes continue to grow as long as the tops are green. Dig only as many as you need for immediate use. The tubers will keep better in the ground than in a warm dry area.
  • Consider planting a cover crop. A cover crop such as annual rye decreases erosion of the soil during the winter, shades out weeds, adds organic material when it is incorporated into the soil in spring, improves the soil structure and adds valuable nutrients. Cover crops can be sown between rows of fall vegetables a month or less before expected harvest. The cover crops will get a head start and not interfere with vegetable plant growth. Buckwheat will be killed by frost but can be sown as a cover crop up to 6-8 weeks before a killing frost, usually about the 3rd or 4th week in October.
  • Garden vegetables that become over-ripe are easy targets for some pests. Remove them as soon as possible to avoid detection by pests.
  • Having trouble locating your tools in the garden amongst your plants? Paint the handles of your garden tools a bright color other than green or tie a piece of bright orange surveyor’s tape around the handle.


During the hot dog days of August, one of the last things a vegetable gardener wants to think about is planting more crops. But look ahead to the fall garden, which offers its own satisfaction through its prolonged harvest of fresh vegetables, savings in food costs and knowing that you are making full use of your gardening space and season.

Thanks for joining us in The Garden Shed. We look forward to you stopping by next month.


“Weed Management on Organic Farms,” , Center For Environmental Farming Systems, North Carolina State

“Why So Many Weeds? The Weed Seed Bank,” Colorado State University Publication 2113,

“August Monthly Tip Sheets – August Vegetables,” (Relf, Diane, Extension Specialist, Environmental Horticulture, Virginia Cooperative Extension-Albemarle County/Charlottesville)

“Fall Vegetable Gardening,” Virginia Cooperative Extension Publication 426-334,






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