When the summer heat kicks in, I’ve noticed some of my plants go from thriving to wilting almost overnight. It’s frustrating watching all that hard work droop in the sun, even when you’re watering regularly.
That’s when I started experimenting with what goes into the watering can—turns out, a little boost can go a long way. Simple ingredients like seaweed extract or a dash of compost tea have helped my plants bounce back faster and stay hydrated longer. Even something as basic as a few drops of unsulfured molasses can make a noticeable difference during a heatwave.
It’s not about fancy products—it’s about giving your plants a fighting chance when the weather gets tough. I’ve found these little tweaks make summer gardening less stressful and way more rewarding.
1. Aloe Vera Gel
The cooling properties that soothe sunburned skin work similarly for heat-stressed plants. A tablespoon mixed into a gallon of water creates a protective coating that helps leaves retain moisture longer.
During last summer’s brutal heat wave, my container garden thrived when I started using this trick. The tomatoes that previously drooped by midday stayed upright even during the hottest afternoons.
For best results, apply this mixture in the early morning before the sun gets too intense. Your plants will absorb more of the beneficial compounds when they’re not fighting against midday heat stress.
2. Epsom Salt
A teaspoon of these magnesium-rich crystals dissolved in your watering can strengthens cell walls, helping plants stand tall when temperatures climb. The additional magnesium boosts chlorophyll production for better photosynthesis even under heat stress.
My garden roses showed remarkable resilience after I began this treatment. What surprised me most was how quickly they responded—within days, their wilting leaves perked up despite the continuing heat.
Try applying this solution once every two weeks rather than with every watering. Too much magnesium can eventually create imbalances in your soil’s mineral composition.
3. Hydrogen Peroxide
A capful of 3% hydrogen peroxide per gallon of water delivers extra oxygen directly to stressed root systems. When heat depletes oxygen in soil, this simple addition can revitalize plants from below the surface.
After hearing about this from an old-time gardener, I tested it on my struggling cucumber vines during a July hot spell. The difference was remarkable—new growth appeared within days despite temperatures hovering in the high 90s.
Just remember that more isn’t better here. Stick with the recommended dilution to avoid damaging delicate root hairs that are already stressed from heat.
4. Liquid Seaweed Extract
Rich in over 60 trace elements, this ocean-derived solution gives plants a complete nutrient boost when they need it most. The natural growth hormones and amino acids help strengthen plants against temperature extremes.
My container herbs that typically surrendered to summer heat showed remarkable staying power after I began adding a few drops to their weekly watering. The basil remained lush and fragrant well into August, long past its usual wilting point.
Unlike chemical fertilizers that can burn roots in hot weather, this gentle option provides nutrition without adding stress to already struggling plants.
5. Aspirin
Crushing one uncoated tablet into a gallon of water creates a solution that triggers plants’ natural defense systems. The salicylic acid mimics compounds plants produce when under stress, essentially preparing them to better handle heat challenges.
The first time I tried this, I was skeptical. Yet my pepper plants—normally the first to flag in high temperatures—maintained their vigor through a week-long heat spell that wilted everything else in the neighborhood gardens.
Consider this a preventative measure rather than a rescue remedy. Starting this treatment before extreme heat hits gives plants time to build their internal defense mechanisms.
6. Coconut Water
Full of natural electrolytes, enzymes and growth factors, a splash of this tropical drink works wonders for heat-stressed plants. The cytokinins it contains help cells divide and grow even when environmental conditions aren’t ideal.
During last summer’s record temperatures, I split two identical hanging baskets—one received regular water, the other got the coconut water treatment. By week’s end, the difference was obvious in both flower production and leaf condition.
Save money by using the liquid from cooking coconuts rather than expensive bottled versions. The natural form contains all the same beneficial compounds without added sugars or preservatives.
7. Chamomile Tea
Brewing a strong pot and adding it to your watering can introduces natural antifungal compounds that protect roots stressed by heat. High soil temperatures often create perfect conditions for fungal problems that attack already weakened plants.
Last August, when my zinnias started showing signs of heat stress and powdery mildew, this gentle remedy helped them recover. I was amazed how quickly the plants bounced back, producing healthy new growth despite the continuing hot weather.
Let the tea cool completely before using it on plants. The beneficial compounds remain effective at room temperature, but hot tea can shock already stressed root systems.
8. Molasses
A tablespoon of unsulfured blackstrap molasses dissolved in water feeds beneficial soil microbes that support stressed root systems. These microorganisms create a stronger soil ecosystem that helps plants access water more efficiently during drought conditions.
The results weren’t immediate when I first tried this method, but after two weeks of treatment, my vegetable garden showed remarkable resilience. Even on 95-degree days, the plants maintained their vigor while neighboring gardens struggled.
Morning application works best since the sugars feed microbes during their most active period. Avoid applying in direct sunlight as the sticky residue can sometimes attract unwanted pests.
9. Cinnamon Water
Steeping a tablespoon of ground cinnamon in water overnight creates a solution with natural antifungal and antibacterial properties. When heat stresses plants, they become more susceptible to disease—this simple spice helps protect them.
I discovered this trick from my grandmother, who used it on her roses during Tennessee summers. After filtering the solution to remove particles that might clog the watering can, I’ve used it successfully on everything from petunias to peppers.
The earthy aroma has an added benefit of deterring certain pests that tend to attack weakened plants. Many crawling insects dislike crossing soil that’s been treated with cinnamon water.
10. Worm Tea
The liquid gold from worm composting contains beneficial microbes that improve soil structure and water retention. Just a cup of this dark brew diluted in a gallon of water gives plants a fighting chance against dehydration and heat stress.
My container garden’s transformation after starting this treatment was nothing short of remarkable. Plants that previously wilted by noon stayed turgid all day, even when temperatures climbed into triple digits.
Unlike chemical fertilizers, this gentle option won’t burn roots or leaves even in extreme heat. The living organisms actually become more active in warm soil, creating the perfect support system during heatwaves.
11. Banana Peel Water
Soaking chopped banana peels in water for 2-3 days creates a potassium-rich solution that strengthens cell walls and improves water regulation. Plants under heat stress often show potassium deficiencies first, making this a perfect remedy.
After reading about this online, I decided to experiment with my struggling impatiens last July. Within a week of treatment, they developed stronger stems that didn’t flop over midday despite temperatures in the 90s. Strain the liquid thoroughly before using to prevent fruit flies.
The resulting clear amber liquid can be stored in the refrigerator for up to two weeks, giving you a ready supply during extended hot spells.
12. Diluted Milk
A quarter cup of milk in a gallon of water provides calcium that strengthens cell walls while the proteins and sugars feed beneficial soil microbes. This combination helps plants better regulate water movement during temperature extremes.
My first attempt with this was purely accidental—leftover milk was headed for the compost when I decided to dilute it for the garden instead. The squash plants that received this treatment bounced back from heat stress faster than I’d ever seen.
Fresh milk works better than the powdered version for this purpose. The living enzymes and proteins provide additional benefits that are lost in the dehydration process.
13. Willow Water
Steeping fresh willow twigs in water releases natural rooting hormones that help plants develop stronger, more extensive root systems. Better roots mean better water uptake during drought conditions and heat stress.
I learned this from an elderly neighbor who used it on everything from roses to tomatoes. After trying it myself during last summer’s heat dome event, I was impressed by how well treated plants maintained their vigor compared to untreated ones.
Harvest young, flexible branches in spring for the highest hormone concentration. Even in summer, though, willow cuttings contain enough of these compounds to make a difference for struggling plants.
14. Compost Tea
Steeping finished compost in water creates a microbial brew that improves soil structure and water retention. The beneficial bacteria and fungi help break down organic matter faster, making nutrients more available even when plants are stressed.
During the third week of a brutal heat wave, my vegetable garden was struggling despite regular watering. After applying compost tea, the transformation was remarkable—new growth appeared and existing leaves regained their color.
Use only well-finished compost to make your tea. Immature compost can contain pathogens or compounds that might further stress plants when they’re already fighting against heat.
15. Diluted Honey
A teaspoon of raw honey dissolved in a gallon of water provides natural sugars and enzymes that boost plants’ immune responses. The complex carbohydrates feed beneficial soil microbes that help roots access water more efficiently.
When my container herbs started showing heat stress last summer, this sweet solution made a noticeable difference. The mint and oregano that had begun to wilt and yellow perked up within days despite continuing high temperatures.
Raw, unpasteurized honey works best for this purpose. The living enzymes and beneficial compounds are often destroyed in commercial processing, reducing the effectiveness for plant health.
16. Cucumber Water
Blending cucumber peels and flesh with water creates a silicon-rich solution that strengthens cell walls and improves heat tolerance. The natural plant compounds help regulate water movement within plant tissues during temperature extremes.
I stumbled upon this remedy while looking for uses for excess cucumbers from my garden. After using the strained liquid on my flower beds during a heat wave, I noticed they maintained their bloom quality longer than in previous hot spells.
For maximum benefit, let the blended mixture sit overnight before straining and using. This allows more of the beneficial compounds to leach into the water, creating a more effective heat-stress remedy.
17. Rice Water
The starchy water left over from rinsing rice contains nutrients and growth-promoting substances that help plants recover from heat stress. Diluted 1:3 with fresh water, it provides a gentle boost without the risk of fertilizer burn during hot weather.
My grandmother always saved her rice water for houseplants, but I started using it outdoors during last summer’s heat wave. The ferns that typically brown and crisp in high temperatures maintained their lush appearance despite record-breaking heat.
Allow the rice water to ferment for 1-2 days before using for maximum benefit. The fermentation process increases the availability of nutrients and develops beneficial microorganisms that improve soil health.