When It’s Just Too Hot: What Extreme Summer Heat Does to Your Garden
It feels like the temperatures during the day have been hovering around 100° for weeks.
And if you walk outside this afternoon and your garden looks wilted, tired, and significantly less impressive that it did a couple of months ago, you’re certainly not alone.
I’m seeing it in my own garden, too.
My poor dahlias haven’t produced a bloom in a couple of weeks. They’re alive. They’re watered. Their foliage looks fine. But right now, they simply aren’t interested in blooming. Sometimes the problem isn’t your watering schedule, your fertilizer, or something eating your plants.
Sometimes it’s just August in Mississippi.
What Happens to Plants When It Gets This Hot?
Plants have an ideal temperature range for growth just like we do. When temperatures climb well beyond that range—especially for days or weeks at a time—their priorities can change.
Instead of putting energy into vigorous growth and producing lots of flowers, a plant may start putting more of its resources toward simply maintaining itself.
That can show up in several different ways:
Fewer or no new blooms
Flowers that fade much faster than usual
Buds that dry up or drop before opening
Slower new growth
Curled or drooping leaves
Wilting during the hottest part of the afternoon
Increased water needs
Scorched or crispy leaf edges
None of those things are particularly pretty, but they also don't automatically mean your plant is dying.
Where Did All the Blooms Go
This is one of the biggest things I notice during prolonged summer heat.
A plant that was flowering beautifully earlier in the season may suddenly seem to stop.
Producing flowers takes energy. When a plant is under significant environmental stress, flowering may become much less of a priority.
Even when a plant continues blooming, those individual flowers may not last nearly as long. A bloom that would normally look beautiful for several days can fade incredibly quickly under intense sun and triple-digit temperatures.
My dahlias are a great example. They've been cared for and watered, but after weeks of intense summer weather, bloom production has slowed dramatically.
I'm not trying to force them back into production right now. I'm keeping them healthy and waiting for conditions to improve.
A Wilted Plant Isn’t Always a Thirsty Plant
This is where summer gardening gets tricky.
You walk outside at 3 p.m. and see a plant completely drooped over.
Naturally, you grab the hose.
But before you water, check the soil.
During extreme heat, a plant can lose moisture through its leaves faster than its roots can replace it. That means a plant can temporarily wilt during the hottest part of the day even when there is still adequate moisture around its roots.
Check that same plant early the next morning. If it has perked back up, that afternoon wilt was likely its response to the heat.
If it is still wilted in the morning and the soil is dry several inches down, then yes—it probably needs a good drink.
Constantly adding water every time a plant wilts can create a completely different problem: chronically wet soil and unhappy roots.
Deep Watering Beats Constant Sprinkling
When your garden truly is dry, give it a good, thorough watering.
A quick sprinkle over the surface may make you feel productive, but it doesn't necessarily put water where your plants need it.
You want moisture to penetrate down into the root zone.
Deep watering also encourages plants to develop deeper root systems rather than depending on moisture right at the soil surface.
During periods of extreme heat, I would much rather see an in-ground garden watered thoroughly when it needs it than given a tiny amount of water every day.
Morning is ideal. Your plants can enter the hottest part of the day fully hydrated, and less water is immediately lost to evaporation.
Containers Are a Different Story
If you're growing plants in pots, you need to pay especially close attention right now.
Containers have a limited amount of soil, and that soil can heat up and dry out incredibly quickly.
During our hottest stretches, some containers may legitimately need water every day. Small pots and containers sitting in intense afternoon sun may need even closer monitoring.
Don't assume that because your flower bed still has moisture, the pot sitting beside it does too.
Stick your finger into the soil and check.
Mulch Is Doing More Than Making Your Beds Look Pretty
One of the simplest ways to help plants through extreme heat is keeping their roots protected.
A layer of mulch helps reduce evaporation, keeps the soil temperature more stable, and protects the upper portion of the root zone from baking in direct sun.
Pine straw, shredded bark, leaves, and other organic mulches can all help.
Bare soil exposed to the Mississippi summer sun gets hot.
If you have an area that seems to dry out almost immediately after watering, adding mulch may make a noticeable difference.
Don’t Try to Fix Everything With Fertilizer
When plants stop blooming, one of our first instincts is often to fertilize them.
More flowers = more flower fertilizer, right?
Not necessarily.
A plant already struggling with extreme heat doesn't always need encouragement to push a bunch of tender new growth. Heavy fertilization during significant heat or drought stress can add another demand when the plant is already working hard enough.
If your plant is otherwise healthy and you've been following a reasonable fertilizing schedule, don't assume a temporary slowdown in blooming means it's starving.
Sometimes it just needs cooler weather.
This Is Also Not the Best Time to Stress Your Plants Even More
If you can avoid it, a 100-degree stretch isn't the time I'd choose for major transplanting, aggressive pruning, or unnecessary root disturbance.
There are obviously times when we have no choice. But if something can wait until temperatures moderate a little, let it wait.
Your plants already have enough going on.
Give Your August Garden a Little Grace
This might be the most important summer gardening advice I can give:
Adjust your expectations.
A Mississippi garden in August is not going to look like that same garden in April.
Spring gives us moderate temperatures, fresh growth, abundant blooms, and plants that seem determined to impress us.
By late summer, they've endured months of sun, heat, humidity, insects, storms, and everything else our climate has thrown at them.
Some plants will still look fantastic.
Others will slow down.
Some will stop flowering for a while.
Some will look downright tired by late afternoon and perk right back up the next morning.
That doesn't mean you've failed at gardening.
Keep an eye on your soil. Water deeply when your plants actually need it. Protect their roots with mulch. Watch for genuine signs of pests and disease. And resist the urge to throw every possible treatment at a plant simply because it isn't looking its best.
Sometimes the best thing we can do is keep our gardens healthy enough to weather the worst of summer and wait.
Because eventually, the temperatures will come down.
And you may be surprised by how quickly some of those tired plants come back to life.
Sometimes it isn't a watering problem. It isn't a fertilizer problem. It isn't a pest problem.
Sometimes it's just August in Mississippi.
