In the Vegetable Garden- August

  • By Cleve Campbell
  • /
  • August 2018 - Vol. 4 No. 8
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“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 Tasks and Tip article has highlighted the “busyness” of whichever month we’re in. Perhaps you’re beginning to believe that every month in the vegetable garden is a busy month. Well, as a vegetable gardener, I must say that certainly seems to be the case! Let’s begin with the short version of the August To-Do list: continue to harvest vegetables, remove spent spring and summer crops, and weed. August is also the time to plant fall crops and cover crops.

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-seed inventory can also be increased with the application of organic matter through 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? Every time a weed is allowed to go to seed, it replants itself in our garden. Okay, by now you’re thinking, “It’s August, it’s hot, and I get 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? Many common weeds have the ability to produce thousands of seeds that are deposited on the earth. Many of these seeds have a protective coating and 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.

This annual collection of seeds, if present in the garden or in the seed bank, makes weeds a tough adversary. It is estimated that the seed bank can be depleted by 80-90 percent within 2-3 years after weed control is started. However, the seed bank can be replenished in only a single year of no control or ineffective 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!

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

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

August is a transition month: the 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 definitely fall planting season. Timely planting is the key to success.

The following planting chart was created by using the Virginia Cooperative Extension Publication 426-334, “Vegetable Planting guide and Recommended Planting Dates.”

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 seed in August. Chinese cabbage, broccoli, cauliflower, and Brussels 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 because they avoid the peak insect activity period of midsummer. However, some insects, such as cabbage worms and corn earworms, may be worse later in the year than in the summer; vigilance is still required. Avoid some pests and diseases by planting crops of different families than those which were originally grown 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 make working the soil difficult and can also inhibit seed germination during the late summer. Plant fall vegetables when the soil is moist, either 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; mulch should cover the soil, not 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

    Buckwheat planted between corn rows.

    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 will 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. For more information on the attributes of growing buckwheat check out the “Buckwheat” article in our August 2016 issue of The Garden Shed.

  • Garden vegetables that become over-ripe are easy targets for some pests. Remove ripe vegetables as soon as possible.
  • Having trouble locating your tools when working in the garden? 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 the satisfaction of a prolonged harvest of fresh vegetables, savings in food costs, and making full use of your gardening space and growing season.

Thanks for visiting us in The Garden Shed. We look forward to your visit next month.


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

“Vegetable Planting Guide and Recommended Dates,” Virginia Cooperative Extension Publication 426-334,

“August Monthly Tip Sheets -Vegetables,”

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











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