13 Must-Dos to Keep Your Houseplants Thriving During the Summer

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Black & Blooms

Fact: we often focus our attention on the plants and flowers in our yards during the warmer months, yet summer can be the most challenging time of the year for indoor plants. Here’s what you can do to keep yours growing and thriving. 

1. Feed Your Houseplants

When was the last time you fed your indoor plants? Exactly. “With longer days, plants are exposed to more sun and require additional nutrients to stay healthy and create new growth,” says Madeline Sachs, Plant Care Specialist at Greenery Unlimited in Brooklyn, New York. How much you feed your plant is dependent on the species and the fertilizer you choose. “From late spring through the fall, I recommend a once-a-month, water-soluble, all-purpose fertilizer or a slow release fertilizer pellet that contains nitrogen, phosphorous and potassium,” advises Sachs. “Some plants can be sensitive to over fertilization, so I find diluting the amount to half the package instructions, at least to start, works best.” During times of extreme heat, postpone fertilizing. “Plants can become stressed due to the heat and may not be able to process the extra nutrients,” adds Peg Reynolds, owner, Reynolds Landscaping and Garden Shop in Manahawkin, New Jersey. Look for fertilizers from brands such as Osmocote, Fox Farm Big Bloom, and Espoma.

2. Up Your Plant’s Moisture Level

There’s no rule of thumb on how often to water houseplants—it all depends upon the plant species and the size of the plant and pot. Monitor the plant and water when the soil starts to dry—typically every seven days, possibly more often during the summer months. While a moisture meter will provide you with the most accurate hydration levels (try: Soil Sleuth Soil Probe, $12, Greenery Unlimited), simply digging a finger down one to two inches into the soil will help determine if the plant needs water. Also, check the soil around the perimeter of the container—if adequately moist, the soil should be touching the edge of the pot. If the soil has pulled away from the edge, the plant needs watering. Air conditioning can dry out houseplants so it’s a good idea to mist them using a spray bottle filled with water during the morning, allowing time for the foliage to dry throughout the day. Another way to increase the humidity? Place the houseplant on a shallow saucer filled with pebbles and water. “The resulting micro-climate will increase the humidity around the plant,” notes Reynolds.

3. But Don’t Overwater

Overwatering is one of the most effective ways to kill a houseplant. Look for signs such as mold or fungus on the soil’s surface, young and old leaves falling off simultaneously, standing water in the saucer, leaves with brown rotten patches or brown edges, or insects around the damp soil surface. “When the soil becomes overly moist it prevents the roots from getting oxygen, so they suffocate and start to break down,” advises Sachs.

4. Water Correctly

While every plant species has different watering needs, it’s important to hydrate the plant well and deeply. “Make certain the water infiltrates into the soil and drains out the bottom of the container. If the plant is very dry, water may have a tendency to drain down the sides of the container and not fully penetrate the soil. If this is this case, apply water to the container a second time to ensure all the soil has been moistened,” says Reynolds. Water at the soil’s surface and not at the leaf tops to prevent mildew and other pathogens from developing.

5. Prevent Leaf Scorch

Glass can act like a magnifying glass, burning and drying out plant leaves. “To avoid reddish-brown sunburned splotches, keep plants a foot away from the window,” suggests Sachs. “Especially when you’re dealing with south and west facing exposures.” There are some exceptions though, including cacti, succulents, ficus trees, and tropical plants which thrive on direct sun.

6. Avoid AC Drafts

Breezes from air conditioning can dry out a plant’s soil and leaves just as effectively as the sun, reducing humidity in the air and leading to brown edging, leaf discoloration and breakage. “It’s important to move plants away from direct exposure to AC drafts,” says Reynolds.

7. Pick Up Leaf Droppings

Removing leaves that have fallen onto the soil is an important sanitary practice to prevent harmful insects and pathogens from collecting in the dirt and at the base of the plant, advises Reynolds.

8. Choose the Right Time to Repot and Prune

Spring is the best time to repot but if you need to transfer plants in the summer, be sure to do so in the early morning or evening when temperatures are cooler and the sun less intense to avoid shocking the plant. “As for pruning, it’s best to wait until the heavy heat of summer has passed before removing any discolored leaves or stems as this can increase stress to plants at a time when they are already stressed,” notes Reynolds.

9. Allow For Outside Plant Time

Most houseplants can be moved outside between May and September. “However, check the safe temperature ranges for your specific plant because they can vary. In general, temps should be above 65 degrees,” says Sachs. “Direct outdoor sun can be much stronger than indoor lighting. Because plants can get easily sunburned, it’s important to move them to a shady area if you notice any signs of scorching.” 

10. Prevent Pests

Bugs can find their way into your home when windows and doors are open. Inspect your plants when you water and look for signs of pests including aphids and spider mites. “Yellow leaves, black spots, or a distorted texture can signal a problem,” says Reynolds. “Also, the appearance of a shiny, sticky substance called honeydew is also a sign of bugs. Dislodge indoor insects from the plant by using the soft spray on your garden hose and if the infestation is severe, try some insecticidal soap and follow the label’s directions.”

11. Wipe Off Dust and Dirt

Indoor pollutants, like pollen and dust, can coat your houseplants and reduce their ability to absorb light and make food through the process of photosynthesis. “A periodic cleaning of the leaf surface will help keep plants healthy,” says Reynolds. “Mix a little dish soap or a tiny bit of Neem with warm water to get rid of dust and any crusty white water marks that may appear due to hard water,” says Sachs.

12. Choose Hardy Houseplants

Opt for resilient and low-maintenance indoor plants in the summer such as bird of paradise, monstera deliciosa, and sansevieria, along with succulents including the string of fishhooks, suggests Sachs. Others, like long-lasting philodendron, spider plants, aloe vera, and rubber plants, can survive in less than optimal conditions, adds Reynolds.

13. Locate a Plant Sitter

Hitting the road this summer? “Try to find a plant sitter to care for your plants when you’re not at home,” suggests Reynolds. “If this can’t be arranged, water your plants thoroughly before leaving and place them in a cool location with little extremes in temperature.” Self-watering planters, where you fill a reservoir so the plant soaks up water slowly from the bottom of the pot are great for people who travel. “They take a little time to initiate so it’s best to set them up a month or two before you leave,” notes Sachs. Watering globes, where glass orbs are filled with water and then slowly release that water into the soil, can also help extend the length of time between waterings.

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