August in the Edible Garden

August in the Edible Garden

  • By Ralph Morini
  • /
  • August 2020-Vol.6 No.8
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Virginia weather has provided a continuing array of challenges to gardeners this year. The warm spring seduced us into putting summer vegetables in the ground early, only to face several frosty nights in May. June offered higher than normal rainfall, focusing us on moisture-loving pests and fungal diseases. As I write this in late July, we are on a multi-week run of high heat and little rainfall. In the first half of July we have had .4 inches of rain compared to a historical full month total of 5.3 inches. Each set of conditions suggests different, sometimes conflicting, gardening practices to maintain plant health. Is it best to plant in a dense pattern to crowd out weeds and shade the soil or space plants to encourage good air flow to reduce fungal pathogen risks? I think the answer is to pick the plan that works best in your garden and adapt as needed. In all cases, maintain good hygiene. Prune diseased vegetation and remove it from the garden, remove sick plants to prevent disease spread, pick pests off crop leaves to reduce plant damage and reduce pathogen vectoring. Now that we are into the high summer heat, mulching is a good idea to help maintain soil moisture, recognizing that mulch can provide refuge for certain pests. There is no single formula for success. Being attentive, understanding the issues that arise, and adapting on the fly is a practical approach. Meanwhile, following the best practices of crop rotation, minimum tillage, companion planting, and regularly adding organic matter to your soil all help minimize serious issues. Gardening is nothing if not a lifelong learning experience. 

Planting a fall crop 

August is the time to plant fall crops. In Hardiness Zone 7a, the first frost is expected in the October 15-25 time period, roughly 70-80 days from August 1. When choosing seeds to plant, be conscious of time-to-harvest noted on the seed packs to be sure the crop has adequate time to mature prior to frost. Cool weather crops, including greens and cole crops, survive frost but growth will slow down as days shorten and temperatures cool. Getting them to a harvestable stage prior to frost is a good idea. In general, choosing varieties with a short time to maturity makes sense.

Per the VA Cooperative Extension publication Virginia’s Home Garden Vegetable Planting Guide,  August is a good time to plant beets, broccoli, cabbage, carrots, cauliflower, collards, kale, kohlrabi, lettuce, mustard, radish, spinach and turnips. Again, comparing time to harvest with time to expected frost is a good practice.

The fall gardening season can be very productive here in central VA. We can enjoy home-grown produce at least through frost, and many greens and cool weather crops remain harvestable well into winter if established prior to cold weather’s arrival. 

More Gardening Tips and Tasks For August:

Tomato blossom end rot: Photo: R Morini

  • Managing tomato diseases becomes critical to maintaining tomato production later in the season. Tomato susceptibility to various blights, wilts, and viruses can be challenging. Regular pruning with disinfected tools, removing plants afflicted with certain diseases, and watching for pests, like tomato horn worm, are all important. For help in identifying specific diseases and taking appropriate action, see the Garden Shed article Tomato Diseases. As an alternative, consider two articles from the Missouri Botanical Garden. This well-illustrated article is helpful in identifying tomato diseases and this one offers information for disease prevention and control. Also, note specific diseases you confront to guide you toward resistant seed and plant selections next year.

Tomato hornworm hosting parasitic wasp cocoons: Photo: R Morini

  • Speaking of tomato hornworm, if you see one that looks like the one in the photo, leave it alone. The white cylinders on its back are beneficial braconid wasp cocoons. The adult wasp injects eggs into the hornworm. Larva feed on the worm’s innards until ready to pupate when they exit and spin cocoons as shown. Tiny adult wasps emerge a short time later. The hornworm may live through the wasp cycle, but will die before pupating.
  • 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 catalog.
  • 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. Avoid some pests and diseases by planting crops of different families than those grown in that garden section earlier in this growing season.
  • When planting fall crops, prepare the soil by restoring the nutrients removed by spring and summer crops. A light layer of compost or application of a balanced organic 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 the day before planting. Plant the seeds slightly deeper than recommended for spring planting. Once planted, water them thoroughly.
  • Watering properly is the key to conserving water and maintaining plant health 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. Water the garden early in the day so the foliage dries before nightfall. Wet foliage at night increases susceptibility to fungal diseases.
  • When mulching around young seedlings, take care not to cover them.  Young seedlings need as much sunlight as possible. Mulch should cover the soil, not the young plants.

Cross striped cabbage worm on kale: Photo: R Morini

  • If you have a problem with cabbage worms on your cole crops (cabbage, kale, collards, broccoli, cauliflower, Brussels sprouts), consider using floating or hoop-supported row covers, pick worms off the plants when you see evidence of chewing or excrement on the plants, and for extreme infestations, use Bacillus Thuringiensis (Bt), an organic and relatively safe pesticide as per label directions. If you protect your plants until the first frost you can enjoy harvesting many of these vegetables well into winter. For more detailed info on the problem and solutions, refer to the article OMG, What’s Eating the Broccoli in the April 2018 issue of The Garden Shed.
  • 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 away. Otherwise, your vegetables will become over-mature and stop producing.

Runaway pumpkin vine. Photo: R Morini.

  • If vining crops like squash and pumpkins are taking up too much of your garden space, it’s ok to pinch off the growing tips. This  will cause the plant to put more energy into fruit maturity, less into vegetative growth.
  • 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.
  • Garden vegetables that become over-ripe are easy targets for some pests. Remove ripe vegetables as soon as possible.
  • When harvesting, don’t let your produce sit in the hot sun for any length of time. Cover, or even better, keep them cool, to prevent loss of succulence, wilting, and conversion of natural sugars to starch.

A Second Chance…

August is kind of a good news-bad news time for home gardeners. The spring plants are expiring, we’re fighting bugs and diseases, and we’re hot and tired. The good news is that removing the old plant material, reviving the soil with fresh compost or organic fertilizers, and planting new seeds or transplants gives us a second chance to enjoy the growing and harvesting periods that make edible gardening so satisfying.

Thanks for visiting us in The Garden Shed. We look forward to sharing experiences again next month.


Monthly Gardening Tips – August, Gardening Resources, PMG

“Virginia’s Home Garden Vegetable Planting Guide: Recommended Dates and Amounts to Plant,” Virginia Cooperative Extension Publication 426-331, Va.Coop.Ext. Digital Pubs and Va.Coop.Ext. Pub. 426-331

“August Monthly Tip Sheets -Vegetables,”

“Selected Vegetable Diseases,”

“Tomato Diseases,” The Garden Shed, June 2015,

“Tomato Fruit Problems,”

Featured photo: R Morini

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