The recent weather has been exceptionally humid and quite hot. This has been very uncomfortable for humans but also takes a toll of the garden. This will be most notable in the vegetable garden as you notice a decrease in your harvest in the next few weeks. Before you panic, looking for problems, be aware that it may just be the effects of the recent hot weather. Blossom drop, failure to flower, slow or stopped growth, dropped leaves and curling leaves are all symptoms of heat stress.
Tomatoes are a good example of plants that are affected by heat. Daytime temperatures between 85 and 95 F and nighttime temperatures above 75 F will cause flowers to drop — no flowers, no tomatoes. Remember, tomatoes are wind pollinated. High humidity will moisten the pollen, making it too heavy to pollinate.
Many other plants will experience similar problems. Blossom drop is common on beans, cucumbers, eggplant, melons, peppers, pumpkins and squash, to name a few.
Cool weather plants will bolt or stop growing. Broccoli, Brussels sprouts, carrots, cauliflower, Chinese cabbage, kale, kohlrabi, lettuce and other salad greens, peas, radishes, spinach and Swiss chard dislike hot weather and seeds started for fall production must be protected with shade.
Heat stresses plants that make them more susceptible to disease and insect problems. They will slow or stop growing as they concentrate on survival.
Container grown plants will experience problems sooner and more severe if not cared for during hot weather.
Protect sensitive plants by:
Water: Keep plants watered. Water slowly and deeply during dry hot periods.
Mulch: Keeps the soil temperature cooler.
Weed: Decreases the competitions for the limited resources in the garden.
Shade: Reduces heat and sunscald problems. Conserves water.
Varieties: Select varieties that are heat tolerant.
So recognize that your garden may need a little extra care during hot or humid weather. Strive to keep them healthy and when temperatures drop to more usual temperatures, your plants will often start growing again, start flowering again and produce more vegetables.
Protect Yourself in Hot Weather
Not only plants, gardeners also are affected by hot weather. You know the drill but do you follow it? The rules for hot water include:
Protect yourself with sunscreen, remember your ears.
Wear a hat and sunglasses to shade your eyes.
Wear loose, lightweight clothing.
Rest often. Have a nice, shady spot, a comfortable chair and a cool drink often.
Drink plenty of water. Avoid alcohol and caffeine.
Garden during the cooler parts of the day — early morning and late afternoon.
Take a cool shower when you come in. Check for ticks — they are most likely to be a problem during humid or wet weather.
Use insect repellant and drain all standing water to discourage mosquitoes.
Parkland Garden Club Garden Tour
Last Saturday was the annual garden tour of the Parkland Garden Club. I was scheduled to be in the second garden, the beautiful garden of Paul and Patty/Patti Huck. I apologize to anyone who sought me out at 11 a.m., my scheduled time. I was late and didn’t arrive until after 11:30 a.m.. However, it was great to meet all those who stopped by later. The location was wonderful. We were on a covered porch with a ceiling fan that overlooked the valley garden that Paul tends daily. Our hostess made icy bottles of water and fresh cookies available for all visitors.
The excessive heat prohibited Fran and me from visiting the other gardens, but I heard they were equally gorgeous and the chickens were a hit with many.
In Our Garden
I have spent little time outside lately. I have noticed that the Mandeville is doing exceedingly well and the gardenias are loving the humidity. Several shrubs, cut back drastically last fall, are recovering and look much better this season. Regenerative pruning is quite effective on some overgrown plants but be sure to research your particular plant before resorting to this.
Sue Kittek is a freelance garden columnist, writer, and lecturer. Send questions to Garden Keeper at [email protected] or mail: Garden Keeper, The Morning Call, PO Box 1260, Allentown, PA 18105.
Week in the Garden
Planting: Start sowing seeds in flats for fall flowers like pansies and snapdragons or ornamental foliage plants like mustard, cabbage and kale. Plant but protect from heat: late-season cabbage, carrots, cauliflower, peas and broccoli for late summer or early fall harvest. Sow seeds that require a cold period for germination. Poppies are one example. Asters and mums are starting to appear on the market. Start thinking about adding to your fall display, either in the garden or as part of a container display. Hold new plants until the weather cools. Gather them together to make watering easier.
Seasonal: Stake tall flowers and provide supports for vining plants. Allow the final flush of flowers to go to seed. Many provide food for the birds and small mammals during the fall and winter. Take cuttings of those annuals that you want to winter over. Order asparagus, rhubarb, bulbs, flower and fruit plants, and shrubs for fall planting. Shop nurseries for end-of-season bargains or new fall arrivals. Weed often and cut off flowers of any weeds you don’t get pulled out. Deadhead flowers and trim damaged, diseased, and dead foliage to keep beds tidy and encourage reblooming. In particular, keep irises and daylilies from forming seedpods.
Allow peony greens to grow until fall and then cut back. Prune summer-flowering shrubs about two weeks after flowering. Stop pinching back helenium, chrysanthemums and asters. Test soil for new beds, Retest soil in poorly performing areas or those that haven’t been tested in the last 3-5 years. Apply corn gluten based weed control in the garden and establish a schedule for reapplication, usually at four to six week intervals
Lawn: Purchase seed for fall lawn projects. Seed, overseed, dethatch and aerate lawns September through mid-October. Purchase broadleaf weed control. Apply broadleaf weed control, September through mid-October. Plan sodding projects and order sod. Install sod as the weather cools, September and October.
Treat for chinch bugs and sod webworms. Cut as needed, based on growth not schedule, to a height of about 2 ½ to 3 inches tall. Use a sharp blade. Keep newly seeded or sodded lawns watered; supplement rain in weeks where less than an inch. Apply preemergent crabgrass control. Fill in holes and low spots in lawn. Apply corn gluten based weed control in the garden; reapply at four to six week intervals.
Chores: Start getting plants ready to bring in. Repot those that need it and pot up those you want to winter over indoors. Harvest crops regularly, at least every other day. Check hoses; replace washers and correct leaky connections. Dump standing water and remove anything that may collect rainwater to help control mosquito populations .Check seed inventory for late-season crops and fall planting. Water any recent plantings and containers anytime we experience a week with less than an inch of rain. Fix damaged screens and garden hoses. Note damaged caulking around doors and windows. Provide deer, rabbit and groundhog protection for vulnerable plants. Reapply taste or scent deterrents. Clear gutters and direct rainwater runoff away from house foundations.
Tools, equipment, and supplies: Check spring equipment and supplies, repair or replace. Sharpen blades, get fresh gas, check and/or replace oil. Send mowers and tractors for tuneup or repair.
Safety: Clear lawns of debris before mowing and make sure pets, children and others are well away from the area being mown. Store garden chemicals indoors away from pets and children. Discard outdated ones at local chemical collection events. Photograph storm damage before clearing or repairing for insurance claims and file promptly. Anytime you are outside and the temperatures are about 50 F or warmer watch for tick bites. Use an insect repellent containing Deet on the skin. Apply a permethrin product to clothing. Wear light-colored clothing, long sleeves, hats and long pants when working in the garden. Stay hydrated. Drink water or other non-caffeinated, nonalcoholic beverages. Even in cold weather, apply sunscreen, wear hats and limit exposure to sun. Wear closed-toe shoes and gloves; use eye protection; and use ear protection when using any loud power tools.