Houseplants can help ease anxiety and stress. Here's how to look after them.

• More and more people are buying plants while in quarantine.
• The human brain is hard-wired to get stress-relieving benefits from being around plants.
• Experts told Insider that the easiest plants for beginners to buy are either the cactus, peace lily, or snake plant, and that they should only be watered when the soil is dry.
• Visit Insider's homepage for more stories.

Plant parenthood has become something of a trend in the last few years, in part thanks to the emergence of glossy, direct-to-consumer online start-ups like Bloomscape. But now, with most of the United States in lockdown, the demand for plants is almost outstripping the supply as people mass-order plants.

Demand for new plants has soared, according to plant vendors, including Bloomscape, The Sill, and Interior Foliage Design.

Studies suggest there is merit to the trend.

Spending time surrounded by nature can reduce mental fatigue and enhance concentration. In fact, being around plants can lower stress so much that an entire branch of therapy known as horticulture therapy exists, dedicated to using plants and gardening to improve emotional health. One 2016 study even found that the amount of green space there was in a neighborhood was a good predictor of how stressed residents were likely to be.

Erin Marino, director of marketing at The Sill, has about 50 houseplants in her New York home, and during shutdown, she's found comfort in being surrounded by nature. "I'm not spending a lot of time outside, so I'm finding that it's been nice to just disconnect with my plants," she said.

And she isn't alone.

"People are starting to pay more attention to the plants that they have in their space now that they're stuck there," said Matthew Schechter, who works at Interior Foliage Design in Woodside, New York. With people confined to their homes, but still wanting to be surrounded by nature, purchasing a starter plant is the easiest solution.

Here are some of the most common questions first-time plant owners have, and some expert answers to them.

What is the easiest plant for novice houseplant owners to buy?

For Schechter, the cactus and the peace lily are the best options for new plant owners.

"When it comes to plant care, you're really just trying to replicate the plant's natural environment," he told Insider. "A cactus is one of the best plants you can own, period. You can go on a trip for two weeks and as long as it's in sunlight, it's going to be 100% fine."

All a cactus needs is a spot by a window sill where it gets at least two to three hours of direct sunlight a day, and a once-a-month watering. Cacti evolved to exist in a dry, sunny environments, making most New York City apartments, which tend to be dry, a perfect home for them.

Shechter also recommends the peace lily for people who are bored during quarantine. "The peace lily is a bit of a drama queen, and the leaves droop over if you don't water it," he said. While some plants will wilt from overmisting, the peace lily, which is indigenous to a warm, tropical environment with constant humidity, can be misted all day long, while its tell-tale droop will let you know when it needs watering.

"If you feel like you need something to do while cooped up in your apartment, it's great because you can mist that thing all day and it'll love it," said Shechter.

Marino's go-to's are the pothos and the Sansevieria, also known as the snake plant.

"If you're walking around New York City, you'd see the pothos at nail salons, doctor's offices, and bodegas," she said. "It's an incredibly hardy plant that is tolerant of a wide range of indoor environments."

Plants feed on light, but the trailing, vining pothos can handle living in a gloomy bottom-floor apartment just as well as a top-floor penthouse. It's known as the cubicle plant at The Sill because it can thrive in a sterile fluorescent office environment.

The Sansevieria is one of the toughest houseplants around, and can handle the low light of New York apartments. "I've been talking to people who left their snake plants in their offices and they're worried about them, depending on when they're back in office," said Marino. "But the snake plant can potentially go a long period without any water."

What are some things first-time plant owners need to know when purchasing a plant?

"I always tell people to just be really realistic with the light that their space gets," said Marino. Now that people are home during COVID-19, it's a good time to assess how much light their home really gets. Is it sunny around noon? Is it dark enough that you have to turn on lights? Knowing how much light an apartment gets is a good way to set first-time plant parents up for success.

"People might not like to hear this but most plants like to be left alone," said Shechter. "A lot of the time I found that when plants don't do well in an apartment it's because it's been loved to death, meaning people water and mist it more than it needs." He suggested people check on their plants no more than once every three or four days, and leave them alone the rest of the time.

Use pots with drainage holes, Joyce Mast, resident plant mom at online plant store Bloomscape, told Insider, as too much water at the bottom of the pot can suffocate plant roots that need air to breathe.

How often should the plants be watered?

"Watering your plant really depends on what type of plant you have, how much light that plant is receiving, as well as what time of year it is," said Marino. "You'll find yourself watering when there's more light in spring and summer."

Marino has about 50 houseplants, and she examines all of them once a week to see if they need watering. In succulents she looks for signs of wrinkling leaves, while in tropical plants she looks for signs of dropping leaves or soil dryness.

"I'm kind of in the camp of under-watering versus over-watering," she said, "because in my experience, plants bounce back easier from under-watering."

Instead of the standard advice of "water your plants once a week," Shechter suggests feeling the soil every week to see if it is dry or wet. If it's wet, you leave the plant alone. If it's dry, add water. "Touching the soil is like the best way for your plants to communicate with you. If you can handle that you're going to be 90% off better than most plant owners," he said.

For soil examinations, Mast suggested a touch test. "Simply push your finger down into the soil about 2-4 inches, depending on pot size, to feel if the soil is damp. If you feel moisture do not water, but if it is dry, water your plant until it flows freely from the drainage holes at the bottom of the pot."

Don't be discouraged if it seems tricky at first

"It's kind of silly to say that 'I'm not good with plants,' or 'I have a black thumb,'" said Shechter. "It's a lot easier than people think. There [are] tons of Instagram accounts and books and people trying to sell you stuff out there, but the truth is either the soil is dry or wet, and you either add water or don't."

"You gain a green thumb through experience. I think it's a myth to think that you're born with one," said Marino. "Plants takes practice, just like everything else, but it's just a really nice accessible, inclusive hobby."

"Don't get discouraged," Mast told Insider. "Sometimes plants take time to adjust to a new environment. Just be patient and your plants will thrive!"