It can be tough keeping plants alive indoors, especially as the dry winter months approach (if you're in the Northern Hemisphere).

But if you can keep them thriving, indoor plants also have all sorts of benefits.

Plants can regulate indoor humidity. Norwegian office workers report that having plants at work helps them stay productive and healthy. In Japan, they fight crime: a Tokyo neighborhood dealing with a spate of break-ins planted flowers and saw burglary rates fall 80 percent.

Even rocket scientists agree: when NASA studied houseplants in the 1980s, the space agency found that they can remove dangerous organic chemicals from indoor air, like formaldehyde, benzene and the industrial solvent trichloroethylene.

Business Insider spoke to New York City plant expert Matthew Schechter, who's been in the family plant business since he was born.

Here are his top six "idiot-proof" plant picks that are perfect for anyone who lacks a green thumb. None of these plants need to be watered unless the dirt they're sitting in is dry to the touch. They are built to survive for up to a month without watering.

6. The Cast Iron Plant

The Cast Iron Plant is originally native to Taiwan and Japan, but was brought to Victorian England in the 1800s, where it was a status symbol plant for the rich. Schechter said these low-lying bush plants have evolved to adapt to "basically any kind of climate."(Wikimedia Commons)

The Cast Iron Plant is originally native to Taiwan and Japan, but was brought to Victorian England in the 1800s, where it was a status symbol plant for the rich.

Schechter said these low-lying bush plants have evolved to adapt to "basically any kind of climate".

5. Janet Craig plant

The glossy leaves on this Janet Craig plant are super-hearty. Schechter said one tough Janet Craig plant once lived in a dark closet for two months and it survived to see the light of day.(Interior Foliage Design)

The glossy leaves on this Janet Craig plant are super-hearty. Schechter said one tough Janet Craig plant once lived in a dark closet for two months and it survived to see the light of day.

Schechter says this one is known as a "workhorse plant" because "not all plants have that big, bushy look, but can tolerate low levels of light."

4. The Mexican Ponytail Palm

The Mexican Ponytail Palm is pet-friendly and used to dry, arid conditions. It can go for two to three weeks without water.(cay enns/Flickr)

The Mexican Ponytail Palm is pet-friendly and used to dry, arid conditions. It can go for two to three weeks without water.

It's ASPCA approved as non-toxic for dogs, cats, and horses.

3. Ponytail Palm

The Ponytail Palm's massive trunk stores up water, and it can do well in low and indirect lighting conditions.(Forest and Kim Starr/Flickr)

The Ponytail Palm's massive trunk stores up water, and it can do well in low and indirect lighting conditions.

"They evolved to be able to withstand periods of dryness" in arid eastern Mexico, Schechter says.

2. Snake plant (aka mother-in-law's tongue)

The Snake Plant is sometimes called "viper's bowstring hemp." The leaves are so strong that the plant fibers were once used to make actual bow strings.(Forest and Kim Starr/Flickr)

The Snake Plant is sometimes called "viper's bowstring hemp." The leaves are so strong that the plant fibers were once used to make actual bow strings.

The plant is desert-ready and stores water in its leaves, so "if the soil's wet, don't add water," Schechter says. That rule of thumb applies to all the plants on this list.

The Snake Plant has "got good juju going for it," Schechter said.

In Nigeria and Brazil the snake plant is considered sacred. Brazilians call it "espada de São Jorge" (St. George's Sword) and often plant it outside their homes because it's believed to have protective qualities.

1. Cactus

The cactus is the only plant on our list that needs a sunny spot to thrive. Cacti are best for places with southern exposure, and at least two hours of morning or afternoon sunlight.(Kat Grigg/Flickr)

The cactus is the only plant on our list that needs a sunny spot to thrive. Cacti are best for places with southern exposure, and at least two hours of morning or afternoon sunlight.

"You only need to water cactus once a month," Schechter says. "And that's being generous."

This article was originally published by Business Insider.