Houseplants bring many benefits into your home, from reducing odors, airborne toxins, and dust to increasing humidity and promoting a sense of wellness. Just how many houseplants do you need, however, to realize those benefits? The answer is more complicated than just a basic number.
Basic Houseplant Calculations
The general rule of thumb for how many houseplants are most effective is one medium-sized houseplant per 100 square feet of room space. This figure is derived from a clean air study conducted by the National Aeronautics and Space Administration (NASA) in the 1980s, using a sealed space environment and determining how houseplants could benefit astronauts. The study was conducted using more than 25 different types of plants, including houseplant favorites such as English ivy, spider plants, peace lilies, aloe vera, and dumb canes.
The problem with this study, however, is that our homes are not space environments and they are far from sealed. Our homes are much larger spaces and have frequent air circulation from heating and cooling systems, open windows, doorways, and imperfect vent seals. We bring contaminants into our homes frequently, from local smog and garage exhaust to cleaning chemicals and perfumes. Because of these differences, the idea that one houseplant per 100 square feet of space is not always applicable to the right number of houseplants for our homes.
How Many Houseplants You Really Need
There are many factors to consider when deciding how many houseplants are best for your home, office, or other living space. When planning how many houseplants you need or deciding to increase or decrease the number of plants you already care for, consider…
- Your Real Square Footage – The actual living space in a home or office can be much different than basic real estate calculations. Closet space, attics, basements, pantries, and other non-living spaces are often included in overall square footage numbers, but you don’t necessarily need plants to purify those spaces. Furthermore, consider if there are rooms in your home that are used very little, such as a guest room or formal dining room. These unused spaces may not need the same houseplant consideration, and you may need far fewer plants in your home than a rule of thumb may indicate.
- Plant Size – Overall plant sizes can play a large role in how effective any single houseplant is for your air purification needs. Medium-sized plants have moderate foliage and are generally grown in 8-10 inch pots. If you use smaller plants, it will take a greater number of houseplants to reach the same benefits. If you prefer much larger plants with broad, expansive foliage, you will need fewer plants in your home to maximize their benefits.
- Plant Type – Not all houseplants are as effective at reducing air pollutants, diminishing odors, and increasing humidity. Plants with more foliage, such as ivies, dieffenbachia, and ferns, tend to be better at scrubbing the air, while less foliated plants such as miniature succulents, cacti, and air plants are less effective. If you have just 1-2 plants with lush foliage, they may be just as effective as 5-6 plants with less foliage.
- Plant Growth – Plants remove more airborne toxins when they are actively growing and producing more roots, foliage, flowers, buds, and offshoots. In spring and summer when plants are in their active growth phases, you may need fewer houseplants to realize the same positive results. If you live in an area with longer growing seasons, that can also impact how many houseplants you need.
- Home Residents – The more people and animals who use the same space, the more houseplants you will need to fully appreciate their benefits. A larger family with multiple pets or more a bustling office in a smaller space will produce more odors and dust, and will require more plants to filter the air.
- Local Air Quality – Different local factors can dramatically impact air quality and influence the number of houseplants you may need. Urban areas with higher concentrations of smog, or buildings near high traffic areas with more vehicles, will have naturally dirtier air and would benefit from more houseplants.
- Personal Preference – The best number of houseplants is often a matter of preference, and some people enjoy being surrounded by many lush plants, while others prefer a minimalist atmosphere with fewer plants. It is easy to choose the right number of plants to suit your preferences and still enjoy their benefits.
Before You Buy More Houseplants
How many houseplants you need is not the same as how many houseplants you can have, and before you buy more plants, it is important to consider just how many plants your home or office can support.
- Do you have enough natural sunlight to support more plants?
- Are you willing to do the proper maintenance and care for more plants?
- Do you have the space to keep more plants without unhealthy crowding?
Ultimately, there is no easy answer for how many houseplants you truly need. By considering how to maximize the benefits of the plants and how many you can properly care for, however, you can decide just how many houseplants are right for you. That number – how many houseplants are right for you and your space – will always be the best number of plants to have.