Summer is here and with the arrival of the heat and humidity, comes the arsenal of more insect and fungal problems.
Water will be evaporating faster and air will be dryer.
This month we’re talking about how to handle powdery mildew issues, what to prune and how it makes your plants produce more, and watering techniques to make sure your plants are getting adequate nutrients and moisture.
So let’s get going!
In the Garden
Powdery mildew is a largely recurring fungal issue for many throughout the summer months.
If you’ve never dealt with mildew, it’s easily identifiable as white or light gray powdery spots that appear on leaves. It can also appear underneath the leaves, on stems, fruits, flowers, or even on the vegetables themselves.
The spores are spread by the wind when it’s warm and dry, then thrive in hot, humid conditions.
So, be sure to remove and discard affected leaves, any that have dropped, and any affected buds.
To prevent mildew as much as possible, only water in the morning, specifically only water around the base of the plant, and really try to keep the foliage dry.
If mildew or other fungal problems persist, get some fungicide. Fungicides are biocidal chemical compounds or biological organisms used to kill parasitic fungi and their spores. Repeat application of a fungicide every 10-14 days.
On the topic of watering, to prevent an excess amount of evaporation, only water in the morning or evening to give your plants a chance to absorb as much as possible before the heat zaps them for the day.
If you’re doing any container gardening, or have any hanging pots, don’t forget that watering these will eventually wash out nutrients that were originally in the soil. To compensate, they will need to be fertilized to replenish the nutrients that are needed.
I suggest using Jack’s Classic Fertilizer at the half dose rate, every other time you water. If any soil has condensed or slowly disappeared, replace it with organic compost such as Leafgro or manure.
Harvest any veggies and fruit when they’re ready. Doing so regularly should improve yields. The characteristics of whether or not something is ready to harvest all depends on which plant we’re talking about. So, if you’re new to gardening, do some research on how to tell if something is ready to be harvested before heading to the garden with a basket. A great example is zucchinis — they’ll keep bearing fruit throughout summer if you harvest on a more regular basis.
Having issues with birds and other animals eating away at your garden? Consider planting animal repelling plants such as marigolds, lavender, Russian sage, yarrow, rosemary, purple coneflower and more. We should have those flowers available (while supplies last), and also carry protective netting from birds, deer and other animals in our Plant Barn.
Now it’s time to talk about what can be cut back. Hardy geraniums and delphiniums can be cut back after their first blooms are done to encourage new growth and more blooms. Mums can also be trimmed back, but I’d only recommend doing so about halfway, and having it done by mid- to late-July. This will encourage the mums to bloom in the fall, rather than sooner.
Similarly, don’t be afraid to cut back your herbs throughout the summer. This will help to keep them bushy and producing.
Consider propagating some pieces to share with friends or family, or to just try as an experiment with little ones!
Side shoots on tomatoes can be trimmed as well. Be sure to cut off any leaves growing below the lowest ripening fruit trusses to improve air circulation and prevent diseases.
If you’re unfamiliar with water sprouts, you’ve still probably seen one before — they’re weak, fast-growing shoots that grow vertically from branches of fruit, redbud, and other ornamental flowering trees. As their name suggests, water sprouts use up large amounts of water and nutrients, all while providing no benefits. They might produce fruit, but the fruit will likely be poor quality and reduced in quantity. Water sprouts tend to emerge after pruning or other damage, and they’re also prone to pests and diseases. So, any water sprouts growing should be removed as soon as they appear.
Any wilting pieces of climbing plants such as clematis should be trimmed. If a piece is unsatisfactory or clearly dying off, the sooner you prune the better. Even when a piece of a plant is dying, it’s siphoning resources that could be nourishing the rest of the plant; so, pruning allows the plant to recognize that it can redirect its energy elsewhere including to new growth.
If you have the need or desire to divide and transplant perennials, it can be done with care. In the event that you decide to do so, a starter plant food, such as BioTone can help prevent transplant shock and allow for the roots to become established. Try to complete everything quickly in the early evening.
You’ll want to keep the root system moist at all times, so they’ll likely need daily watering until they’re established. Of course if there’s consecutive days of rain, you can give them a break for a day or two.
Finally, after all of the care and cutting back has been done, if you’re still itching for more gardening you could think about starting seeds for fall crops. Consider what you’re wanting to plant and think about prepping your garden. Broccoli, kale, turnips and cauliflower seeds should be planted in their containers by the third or fourth week of July. Any later crops like squash, beans and cucumbers can be directly planted into the ground through the end of July.
In the House
Although you’re watering more often now that it’s summer, try not to water on a strictly consistent schedule. Plenty of houseplants need to dry out a little, if not completely, before being watered again. To avoid risking root rot, check on your plants by lifting them.
If you tend to water with a heavy hand, make sure you’re checking that the water is permeating further down into the soil. If the top layer of soil is holding all of the moisture and the bottom majority is bone dry, consider bottom watering to give your plant its own time to absorb what it needs. Bottom watering is when you fill a container with water, then place your plant pot in the container, allowing the plant to soak up what it needs, then once it’s full you remove it, and let it drain. Some people find bottom watering to be easier or better for them, but it truly depends on what works best for you and what kinds of plants you have. Although, for African violets in particular, bottom watering is the best method to avoid getting their foliage wet.
The air indoors will likely be extra dry throughout the summer due to windows being closed or air conditioners running. Visual signs of trouble include curled leaf edges or browning tips. If this is a prominent issue for you, your plants want more humidity. So, think about grouping more together, or if they’re already grouped together consider getting a humidifier. Most houseplants are from tropical regions where it’s almost constantly humid, so a humid environment is one they’ll be the happiest in.
In the Pond & Yard
For pond owners, make sure you’re planting floating pond plants, like water lilies, away from any splashing fountains. Floating blanket weed can be removed by twirling it around a stick or other long object from the garden. Before discarding or composting, put it into a pile close to the pond for a few hours that way any displaced critters can crawl back into the water.
If you have fish, remember water has a difficult time holding onto oxygen in hot weather.
An aerator will boost the oxygen if you keep it running alongside your waterfall 24/7.
Having water in the yard tends to mean you deal with a lot of mosquitos. Just living on the Eastern Shore likely means you deal with them. If bug spray and citronella aren’t working, consider trying mosquito dunks. They’re small donut shaped pods made of a biological larvacide called BTI (Bacillus thuringiensis israelensis). BTI is a bacterium that naturally kills mosquito larvae before they can grow up to become flying, biting, disease-spreading adults.
Even if you don’t have standing water you can make a dunk. If you already have standing water somewhere in your yard you’re already halfway there, if not you’ll want to create standing water in a pot and add some grass clippings. Get your mosquito dunk, set it in the water, and it should go to work killing any mosquito larvae for up to 30 days.
Any hummingbird and oriole feeders need to be kept clean and filled with fresh food. Sugar water will go bad very quickly in hot weather, so plan to change the food every two to three days, or even sooner if the feeder is in direct sun.
To Close
Be sure to check your gardens weekly. If you find a problem, simply bring in a sample and pictures, and we’ll help you diagnose, and address the issue. Have a safe and wonderful July 4 celebration!
(Editor’s Note: Ken Morgan is the owner of Robin’s Nest Floral and Garden Center in Easton, Md.)