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The Dog Days of Summer

gardeners trowel, gloves, and hat

The dog days of summer can be tough on the 3 P’s: people, pets, and plants. All three require proper care and an appropriate amount of water to survive the season’s heat.


As the temperature rises, many plants slow their photosynthesis and close the small openings in each leaf--called stomata--to reduce water vapor loss. These controlled openings allow gas and water vapor to enter and exit the leaf, providing carbon dioxide for photosynthesis, releasing the oxygen produced by that process, and managing the moisture content within a leaf. Down in the soil, an established root system is also extremely important to meet the demands of the extreme temperatures. In a garden, watering deeply and applying mulch is critical for roots to seek and hold the moisture needed for a plant to survive. 


In the lawn, setting the cutting blade of the lawn mower higher in the summer is very important, as it enables roots to grow deeply to find soil moisture during the hot summer. There is a proven correlation between the height of the grass blade and the depth of the root system of a grass plant. Plainly stated, scalping the lawn all season is detrimental to the sustainability of a lawn.


Around Virginia, lawns are typically comprised of fescue, Bermuda grass, and zoysia grass. If a lawn is green in the winter, it is a cool weather preferring fescue. A mat-like growing lawn that stays green in the summer and turns tan/brown in the winter is a warm weather preferring Bermuda grass. Much like Bermuda grass, zoysia grass thrives in the summer heat, creating a short, dense turf that is soft to the touch, and turns tan in cool temperatures.


Fescue lawns go dormant in the summer heat, requiring little to no mowing for the duration of the drought-like conditions. At Maymont we do not irrigate the 60+ acres of lawns that are a mix of fescue and Bermuda grasses. Each summer as the fescue goes dormant, we do not water. After each rain, the beige dormant lawn becomes green once more, and comes back lush and strong. 


To improve the health of Maymont’s lawns, the mower cutting blades are raised to 4” when temperatures reach 90 degrees and are then lowered to 3” in September as the temperatures fall back into the 80’s.  Keeping the mower blade higher enables the grass to grow the deep root system it needs to survive stressful summer conditions.


Unlike lawns, container plants need extra water during the summer heat to stay turgid and healthy. This constant watering leaches nutrients away, making it important to fertilize plants regularly. At Maymont we water regularly with a water-soluble fertilizer at 50% of the dilution rate recommended on the product label. The containers are drenched with the solution after a thorough watering to ensure the roots are turgid and not stressed by the fertilizer. If there are any salts in the fertilizer, the higher concentration of salt will wick moisture away from within the roots and out into the soil, which is the opposite action the plant requires to stay alive! 


Just like in the garden, conserve moisture by mulching the soil surface of container plantings to reduce water loss through soil surface evaporation. Remember to place a saucer under the container to retain some water for uptake later. Never let a plant sit in water for an extended time or the roots will become waterlogged, leading to loss of oxygen and rot. Plus, standing water is the perfect environment for breeding mosquitos!


Speaking of mosquitos, take time after each rain to dump any standing water captured in odd places in the yard to reduce the population. No standing water equals no mosquitos. Did you know mosquitos typically do not fly more than 100’ from the water source they were bred in? Black corrugated drain pipe is a primary breeding ground for mosquitos; upend the pipe to remove the water within.  Keep in mind, some mosquitos require as little as a single tablespoon of water to breed in. I think a quick walk around after rain is time well invested to reduce the discomfort caused by mosquitos.


While it is no longer early July, there’s still just enough time to cut back any Catnip and Catmint or Nepeta sp. growing in the garden to encourage a flush of new growth that will bloom later in the season. I know many fellow gardeners are being plagued by spider mites this year, and due to a severe infestation in my home garden, I cut back my Nepeta ‘Walkers Low’ weeks ago. I then removed the infested debris from my landscape--it is not suitable for composting. I am about to cut back my mints, oregano and sages to 4” to control the mite infestation on those plants, too. I will then apply a slow release fertilizer to encourage healthy new growth after spraying the remaining growth/stubs with very cold water to dislodge the remaining mites. Again, I will dispose of the clippings off-site and wash my gloves before using them elsewhere in the garden.


As mentioned in one of our recent Tips from Maymont, July is the month to plant seeds of determinate tomato plants. Determinate tomatoes, or "bush" tomatoes, stop growing when fruit sets on the top bud (the ‘Celebrity’ tomato featured in that segment did produce abundantly and then stopped). The first frost is months away, providing plenty of time for a flush of fruit from fresh tomato plants that are cultivars bred to be determinate. 


Leave indeterminate tomato plants be. Tomato plants stop producing when temperatures reach over 90 degrees, but they will continue to produce fruit once the temperatures creep back down. Can’t tell the difference between determinate and indeterminate tomatoes in your garden? Let them be and make a point to save the tags next year to be aware of who is growing in the garden (As a side note: keep in mind all plants are living organisms since they do respire/breathe, so I refer to them as “who”).


July is the perfect time to evaluate the bloom sequence in the border, the gaps of production, and empty space in the vegetable garden. Take pictures of the gardens with a date stamp to use as a reference when making plans in the winter for next year. To make the most of your space this year, now is the perfect time to plan the fall vegetable garden. Many of the cool season cole crop seedlings are available at your local garden center in mid-to-late August. September’s cool night temperatures provide the right conditions for a final crop of the season before frost sets in. Reference this planting chart provided by Virginia Tech to determine what and when to plant for a bountiful fall harvest.


As I reach for my wide brimmed hat, sunscreen, water, and gloves remember to take care of yourself out in the heat as well, 


Thank you for watching VHG and…

Happy Gardening,


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