Summer heat can test even the most experienced gardener. A string of days above 90°F, paired with warm nights and drying winds, places enormous stress on plants. Yet many losses during a heat wave aren't caused by the weather alone. They result from well-intentioned mistakes made by gardeners trying to help.
Understanding how plants respond to extreme heat can help you avoid unnecessary damage and keep your garden healthy until cooler weather returns.
1. Watering Too Often, But Too Shallow
One of the most common mistakes is giving plants a quick sprinkle every day. While this wets the surface, it rarely reaches the deeper roots where plants actually need moisture.
Shallow watering encourages shallow root systems, making plants even more vulnerable when temperatures soar.
Instead:
- Water deeply one or two times each week, depending on your soil and rainfall.
- Water early in the morning whenever possible.
- Allow the moisture to soak six to eight inches into the soil.
- Check the soil before watering again rather than following a strict schedule.
Container plants are an exception. Pots dry much faster than garden beds and often require daily watering during prolonged heat.
2. Fertilizing Stressed Plants
When plants begin to wilt or stop growing, it's tempting to assume they need fertilizer. In reality, heat stress often causes plants to slow their growth intentionally.
Applying fertilizer during extreme heat can create additional stress by encouraging tender new growth that cannot withstand the weather. Excess fertilizer may also increase salt concentrations around the roots, making it harder for plants to absorb water.
Wait until temperatures moderate and plants begin growing normally again before feeding them.
3. Pruning During Extreme Heat
Heavy pruning removes valuable foliage that shades stems, fruit, and developing branches.
Leaves are the plant's natural sunscreen. During a heat wave they protect bark from sunscald and reduce water loss.
Avoid:
- Heavy pruning of shrubs
- Removing large limbs from trees
- Cutting back perennials severely
- Deadheading excessively if plants are already struggling
Instead, postpone major pruning until cooler weather returns. If something must be removed because it is dead or diseased, make only the necessary cuts.
4. Leaving Bare Soil Exposed
Bare soil acts like a skillet in July. Direct sunlight can drive soil temperatures well above the surrounding air temperature, damaging fine roots and causing moisture to evaporate rapidly.
A layer of mulch helps protect the root zone.
Good choices include:
- Pine straw
- Shredded bark
- Wood chips
- Leaf mold
- Compost
Maintain two to four inches of mulch around most landscape plants, keeping it a few inches away from trunks and stems to prevent rot.
Besides conserving moisture, mulch helps moderate soil temperatures and reduces weed competition.
5. Ignoring Signs of Heat Stress
Many gardeners panic when leaves wilt during the afternoon and immediately reach for the hose.
But temporary afternoon wilting isn't always a sign that plants need water.
Many plants recover naturally as evening temperatures fall.
Before watering:
- Check the soil several inches below the surface.
- Look for recovery in the evening.
- Watch for repeated morning wilting, which is a stronger indication that watering is needed.
Persistent wilting, scorched leaf edges, flower drop, and premature fruit drop are signs that the plant is struggling beyond normal heat response.
Bonus Tip: Know Which Plants Need Extra Attention
Some plants handle heat surprisingly well once established.
These include:
- Lavender
- Rosemary
- Coneflower (Echinacea)
- Black-eyed Susan (Rudbeckia)
- Sedum
- Lantana
- Yarrow (Achillea)
Others need closer monitoring during prolonged heat, especially if newly planted:
- Hydrangeas
- Hostas
- Lettuce
- Spinach
- Impatiens
- Newly planted shrubs and trees
Young plants with undeveloped root systems are almost always the first to suffer.
Let the Garden Rest
Perhaps the greatest mistake is believing something must always be done.
During a heat wave, nature often benefits from restraint. Resist the urge to fertilize, prune, or constantly disturb the soil. Keep plants watered appropriately, maintain a protective layer of mulch, and allow them to conserve their energy.
Most established plants have survived countless hot summers before. Given proper care and a little patience, they'll usually recover when cooler temperatures and autumn rains finally arrive.
A gardener's wisdom is often measured not only by what he does, but by knowing when to leave well enough alone.
Return to GoGardenNow.com
Posts
No comments:
Post a Comment