As we enter the heart of the summer growing season, spring plants may already have finished, summer vegetables are in full swing and we increase our focus on moisture management, insect and disease issues and caring for idled beds. There is still time to plant warm weather crops like beans, cucumbers, eggplant, melons, okra, peppers, pumpkins, squash, corn, sweet potatoes and tomatoes. With an average first frost date of October 15-25 in our hardiness zone 7a, pay attention to the time-to-harvest information of the crops you plant to be sure you give them enough time to mature before frost risk. Also, if you plan to make a fall planting, consider crop rotation and companion planting to reduce disease and pest risks. Also consider the sun blocking effects of tall and trellised plants based on the needs of the new crop plantings.
Check the Vegetable Harvest Guide from the Iowa State Extension for typical time from seed planting to harvest for common garden vegetables. For a listing of recommended planting and harvest times for hardiness zones 6a-8a refer to VA Cooperative Extension (VCE) publication Virginia’s Home Garden Vegetable Planting Guide.
Planting time for fall crops like lettuces, cabbage family crops and greens begins in early to mid-August, so begin to prepare beds for those plantings. Remove spent plants. Compost them if not diseased and if they haven’t set seed. Otherwise, it is best to dispose of them.
If you started a compost batch in the spring, and kept it moist and aerated, it may be ready for use now. Screen it to separate fully and partly decomposed material. Put undecomposed material back in the bin, while adding finished compost to beds, prior to planting, to give fall plants a boost. Organic fertilizers can also be added to beds prior to planting to give soil life a chance to make nutrients accessible to the new crops. Find basic fertilization info in the Garden Shed article A Fertilization Primer: Plant Needs, Fertilizer Choices and Application Tips.
Maintaining Plant Health
Rotating crops is an important priority to minimize disease and pest proliferation. A three-year cycle is recommended. Interplanting or mixing a diversity of crops into shared space is a good practice too.
Splashing soil onto plants during watering is a common mistake that can spread soil borne diseases onto crops. Water at the plant base, as gently as possible to minimize splashing. Watering early in the day gives vegetation time to dry, reducing risk of fungal disease. A light straw or leaf mulch can reduce soil splashing while helping to conserve soil moisture during hot, dry summer weather.
Advice for Tomato Growers
Tomatoes are a prized summer crop for many of us. It is best to support plants with stakes or cages. If you use stakes, tie plants loosely to the stake with a soft twine or cloth strip. Add ties to give support as plants grow and fruits develop. Remove leaves that touch the ground to reduce susceptibility to soil pathogens. Allow up to two main stems and pinch off all other “suckers” that sprout at leaf/stem intersections. This focuses the plant on fruit production rather than vegetative growth.
Cages require more upfront investment and off-season storage space but reduce plant maintenance during the growing season. If you use cages, prune plants to 3 or 4 main stems. The additional vegetation will help protect fruit from sun scald.
In all cases, remove diseased foliage with shears disinfected with a 10% bleach solution. Bag and remove it with your trash. As noted above, mulching helps maintain moisture, hold down weeds, and reduce soil splash during watering.
A more complete guide to growing tomatoes is provided in the VCE publication Tomatoes. If you have disease issues, check the Garden Shed article Tomato Diseases.
If you are having disease or pest issues, record the timing and specific issues in your journal. This info can assist in selecting resistant varieties next season.
Summer Pests
Summer is the peak activity period for many garden pests. Get help dealing with common pests from the Garden Shed article Eleven Common Garden Pests: Identification and Management.
For more help identifying beneficial insects check the video Garden Insects: Friend or Foe, from the University of Georgia Extension.
More ideas to help maintain garden health during July:
- Watering is extra important in the hotter months, affecting overall plant health, and the taste and texture of many vegetables. The garden typically needs about an inch of water per week, more during very hot periods. Early morning is the best time to water: it gives leaves time to dry before dark and reduces susceptibility to fungal diseases.
- Rain barrels are a great tool for reducing summer water use. They can reduce runoff, conserve water resources, and reduce water/sewer bills. Natural rainwater is also better for plants than chlorinated water. Rain barrels are located alongside downspouts and connected via a pipe or tube. Rainwater passes from the gutter to the downspout and through a diverter that sends it to the barrel. When the barrel is full, excess rainwater is sent down the downspout. Rain barrel water isn’t considered potable and can pick up pathogens from fecal matter on roofs, so should be applied to the base of plants, not sprayed on foliage. The benefits of rain barrels are discussed in the publication Rain Barrels in the Home Garden from the U of Minnesota Extension.
- It’s important to control weeds around vegetables because weeds can out-compete vegetable plants for nutrients, water, and sunlight. The best method of control is by mechanical extraction, meaning good old-fashioned weed-pulling or the use of a hoe. For small weeds, the “stirrup” hoe (also called “hoop” or “scuffle” hoe) is recommended because its shallow soil penetration removes weeds without bringing buried seeds to the surface where they can germinate. It’s also easy on the knees and back.
- Fusarium wilt of Basil is a fungal disease specific to sweet basil. The fungus attacks the water-conducting tissue (xylem) within the stem. Infected plants will grow normally until they are six to twelve inches tall, then suddenly wilt. The stem may become curved and develop brown streaks. The fungus can over-winter and survive many years as spores, ready to cause new infections in basil or other mint family members that are planted in the same soil. There is currently no fungicide approved for its treatment, but it can be controlled somewhat by removing diseased plants, rotating planting locations, and by planting disease-resistant varieties. Some resistant varieties include Aroma-2, Prospera and Obsession. Also, Lemon and purple basil varieties show resistance to the disease. Additional information is available from the UMD Extension publication Fusarium Wilt of Basil and from Garden Shed article Basil: Beautiful and Aromatic.
- Cucumbers develop a bitter taste if the soil is not kept consistently moist. Leaf or straw mulch can help maintain soil moisture.
- Reduce potato watering when flowers mature. Pick them after flowering when the vines dry up. Water and fertilizer may disturb the dormancy stage causing regrowth and may cause potatoes to crack. Great guidance for growing potatoes is available from this article from the Michigan State University Extension.
- Pests and diseases are very active during the summer. It is tempting to use manufactured chemicals to deal with them, but for environmental and health reasons we recommend following Integrated Pest Management principles in dealing with these issues. The Garden Shed article Integrated Pest Management provides good guidance.
- If you use insecticides on vegetables (we hope you don’t), avoid spraying flowers and check the label to understand how long to wait after application before safely harvesting and eating. Please avoid neonicotinoids which present high risk to pollinators.
I hope this information is helpful and that we can talk again next month as fall planting and soil care issues take the spotlight. Meanwhile, enjoy July.
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Feature image: Mid-June Edible Garden, Photo: R Morini
