SerpApi.Org
If you're a home gardener and you notice some of your plants experiencing slow growth in the summer, it can be tempting to fertilize them again. And yes, continual fertilizing is necessary for certain plants, such as tomatoes and cucumbers. However, re-fertilizing in mid-summer is actually ill-advised for many other plants; namely, certain Mediterranean herbs and summer berries.
But why exactly is this? To learn more, Parade consulted with two gardening experts: Donna Letier, a gardener and the Co-Founder and CEO of Gardenuity, and Oscar Fortis, a gardener and the Regional Sales Manager, Western US for True Organic.
When it comes to fertilizing plants, "during the heat of summer, less is often more," Letier explains to Parade. "A half-strength fertilizer applied consistently is usually better than a full-strength application that overwhelms a heat-stressed plant. The goal is to support steady, healthy growth—not force the plant to grow faster than summer conditions allow."
Related: The 39 Best Raised Garden Bed Ideas to Transform Your Outdoor Space
She also explains that choosing how often to fertilize a plant depends if it's growing in a container or in the ground.
"Container gardens can lose nutrients much faster. Plants that are planted in the ground have more access to a larger reservoir of nutrients, so summer fertilizing recommendations can be different," she advises.
Curious to learn which nine plants you should stop fertilizing in mid-summer—as well as five that you definitely should fertilize in mid-summer? Keep reading!
You Should Stop Fertilizing These 9 Plants in Mid-Summer, According to Gardeners
1. Lavender
Both Letier and Fortis agree that fertilizing lavender in mid-summer is a no-no, as it leads to soft and weak growth.
As Letier explains, lavender originates in the Mediterranean, where the summers are known for dry heat and the soil is rocky. Because of this, "fertilizing during mid-summer can encourage soft, leaf growth and the tender new growth is more vulnerable to heat stress," Letier says.
"If you fertilize your lavender in the spring and fertilize it again in mid-summer, it can cause weak and floppy stems," says Fortis, noting that fertilizing your lavender in the summer can also cause poor flower production.
"A good rule to follow is to water deeply but infrequently, allow the soil to dry between waterings, deadhead spent blooms and make sure the plant has excellent drainage," adds Letier.
2. Rosemary
Rosemary, another Mediterranean plant, "naturally slows its growth during extreme heat," explains Letier.
"Fertilizing would encourage excessive leafy growth and the plant would reduce its concentration of the aromatic oils," she adds. "During really hot spells, the plant will conserve its energy rather than producing new growth."
3. Sage
Similarly, sage is from the Mediterranean, so it flourishes in hot, dry summers with "poor" soil, according to Letier.
"During periods of extreme heat, sage naturally slows its growth, so fertilizing isn't necessary and can actually encourage tender new leaves that struggle in the heat," she explains. "If you're growing sage for cooking, too much fertilizer can also dilute the rich flavor that makes it such a favorite in the kitchen."
Additionally, "healthy sage prefers to be a little on the dry side rather than constantly wet," according to Letier. To help your plant thrive, she recommends harvesting it regularly, making sure it has good air circulation and watering it deeply (but only once the soil is dry).
Related: 7 Psychological Benefits of Gardening, According to a Psychologist
4. Thyme
Another Mediterranean herb that likes dry and hot weather, thyme "has never needed rich soil to thrive, so fertilizing during mid-summer usually creates more leafy growth than flavorful growth," says Letier.
"Like many Mediterranean herbs, thyme naturally conserves energy during periods of intense heat instead of trying to produce lots of new foliage," she adds. To help your thyme plant flourish in summer, make sure the soil is well-drained, avoid overwatering and always trim the stems a bit after flowering.
5. Oregano
Oregano is yet another Mediterranean plant that has adapted to hot summers.
"Fertilizing during the hottest part of summer can encourage rapid, tender growth that is less flavorful and more susceptible to heat stress," says Letier. "A good rule to follow is to harvest often, water only when needed, and avoid overfeeding. Regular harvesting encourages fresh growth naturally, without forcing the plant with fertilizer."
6. Raspberries
Fortis says the ideal time to fertilize raspberries is in the spring—never in summer.
"Feeding raspberries in mid-summer will force more leaf and stem growth at the expense of the fruit," he notes.
7. Blackberries
You should only fertilize your blackberry plants in the spring, according to Fortis.
"Like raspberries, feeding blackberries in mid-summer will force more stem and leaf growth," he explains. "The fruit will be sacrificed."
8. Echinacea
Interestingly, echinacea plants do not need to be fertilized at all.
"Mid-summer fertilization is a no-no for this plant because it will cause weak stems and affect the plants immunity," explains Fortis. "It can also make it prone to increased diseases. Echinacea is the kind of plant that does better with no fertilization because it is native to nutrient deficient rocky prairies."
9. French tarragon
French tarragon, which is native to Europe and western Asia, grows best in well-drained soil with "moderate" fertility, according to Letier.
"During periods of intense summer heat, it naturally slows its growth and doesn't benefit from additional fertilizer," she warns. "Feeding it at this time often encourages weak, tender growth that struggles in high temperatures."
To help French tarragon thrive, make sure to keep the soil evenly moist, regularly harvest stems and give the plants some shade if the weather is hot.
Related: 35 Magical Fairy Garden Ideas To Enchant Your Backyard
Gardeners Say You Should Always Fertilize These 5 Plants in Mid-Summer
1. Tomatoes
Both Letier and Fortis concur that tomato plants are "heavy feeders" that require mid-summer fertilization.
"Container-grown tomatoes especially benefit from regular feeding because nutrients are quickly washed out of the soil with frequent watering and from enjoying morning sun and afternoon shade," explains Letier.
She advises fertilizing tomatoes when the soil is already moist—either early in the morning or right after you water them—and never during the hotter parts of the day, as this can give the roots stress.
When it comes to fertilizing tomatoes, Fortis recommends using an organic fertilizer with calcium, such as an organic granular or pelletized fertilizer.
2. Roses
"Roses are heavy feeders and a mid-summer application of fertilizer will help promote continued growth and blooming," explains Fortis. For rose plants, Fortis recommends a high phosphorus organic fertilizer.
3. Bell peppers
According to Letier, because peppers originated in Central and South America, they do well in hot weather. This means you should fertilize them consistently—but lightly—to support their growth.
"Water first, then fertilize early in the morning or later in the evening when temperatures are cooler," she advises. "During extreme heat, reduce the amount of fertilizer rather than increasing it. More fertilizer won't overcome heat stress."
4. Basil
If you've ever had a basil plant, you know that this herb grows very quickly in the summer, something that Letier says is thanks to basil's origins in tropical parts of Asia.
"Every time you harvest basil, you're asking the plant to produce fresh leaves, which requires nutrients," she explains. "Container-grown basil benefits from regular, light fertilizing throughout the summer because frequent watering quickly depletes nutrients from the potting mix."
To best fertilize your basil plants, do so after harvesting and when the soil is moist.
5. Cucumbers
Cucumbers, which originated in South Asia, also grow very quickly in the summer. And interestingly, "as long as the vines are actively producing flowers and cucumbers, they continue to benefit from consistent nutrition," says Letier.
She recommends fertilizing your cucumber plants (especially if they are container-grown) frequently, and ideally early in the day after watering them. Additionally, watering your cucumber plants consistently is vital "because uneven moisture is one of the leading causes of bitter cucumbers."
Up Next:
Related: Amazon's $19 Solar Elephant Statue Adds an 'Adorable' Whimsical Touch to Patios and Gardens
Sources:
- Donna Letier, Co-Founder and CEO of Gardenuity
- Oscar Fortis, gardener and the Regional Sales Manager, Western US for True Organic
