Growing on Air: How Aeroponics Turns Less into More

Starting a garden in or outside can require an extensive list of extras, not the least of which includes choosing the appropriate growing media, adding plenty of the right nutrients and managing the liberal but cautious application of water.

The equation “less is more” just doesn’t compute for many gardening enthusiasts who learned early on that "more" usually translates to bigger plants and better yields. In fact, the idea that plants can grow just fine without soil and hardly any water may seem downright absurd to some.

What we know as aeroponics today first became popular as a bare bones gardening technique that allowed plant scientists to get up close and personal with the mysteries of botany by making plant roots easier to see and study.

Soilless growing has been around for a long time. But the notion that plants can survive long-term with their roots swaying in the air came as a big surprise to early researchers.

An even bigger surprise came when scientists discovered that plants grown aeroponically didn’t just survive; they flourished. As it turns out, they often outperformed their counterparts grown either in soil or water.

How Aeroponics Works

In an aeroponic system, plant roots aren’t anchored to a grow medium like dirt, rock wool, coir, vermiculite or perlite. Instead, they’re secured to a support platform by a flexible collar, often made of neoprene foam rubber, affixed to the plant’s stem.

The crown—the leafy, sun-loving top of the plant—is positioned above the platform, while the root system hangs below in an enclosed or semi-enclosed chamber.

The root chamber is airy, with plenty of room for the roots. It is also outfitted with a network of spray nozzles that mist the roots with liquid nutrients and water on a regular schedule.

Nutrients that aren't absorbed by the roots are returned to a reservoir and recycled.

It’s a simple idea: eliminate the middleman—the media—and supply a plant’s nutritional needs directly to its roots using tiny water droplets that can be absorbed easily.

The platform used to support the plants can be large, small, horizontal, angled or vertical. It doesn’t matter as long as the roots are protected and have consistent access to the nutrient mixture.

It’s a pretty ingenious system that’s scalable. It's also flexible enough to accommodate different types of growing situations.

If you were a plant, you’d probably love growing in an aeroponic system. You wouldn’t have to struggle through layers of soil or inert anchoring media to find nutrients or water.

Both these essentials would be delivered right to your roots, where they could be absorbed efficiently through osmosis. Oxygen, and plenty of it, would be available to help maximize your growth rate by increasing the conversion of sugars into energy. There would even be few --if any-- pests to deal with.

To a basil plant or lowly spud, that would be living the good life.

Aeroponics allows plants to devote more energy to doing what they do best—growing. This translates to faster starts and better yields.

By some estimates, growing aeroponically increases plant growth by up to three times, vastly out-shadowing plants grown in soil. Plants grown aeroponically also thrive on less fertilizer.

Fertilizer that isn't used right away is then recirculated, becoming 100% available to plant roots at future feedings. This way very little is wasted.

Plants grown in air need less space because they aren’t competing for nutrients. A smaller overall growing footprint allows for a more efficient use of space and essentials like light.

Aeroponics is such an efficient growing method that NASA has been one of its biggest supporters since the 1990s. The first space vegetables were part of an aeroponics experiment conducted in orbit in 1995 using potatoes.

If astronauts can grow aeroponic crops in space, imagine how easy it is to garden aeroponically in your greenhouse, grow room, basement or garage.

Advantages of Aeroponics

Faster & predictable growth: Plants produced aeroponically grow fast and with relative uniformity.

This can mean getting a jump start on spring planting, adding an additional lettuce crop during a season or being able to clone new plants from established stock quickly and with fewer losses.

Higher yields: Because plants have a buffet of nutrients available to them almost continuously, they typically set and develop fruit quicker and produce more abundant yields.

Improved flavor: Some growers and aeroponics enthusiasts report that aeroponically-grown food crops have richer flavor profiles than plants grown almost any other way.

Increased flexibility: If you want to change the nutrient solution you’re using, it’s relatively easy to switch to an aeroponic system.

There’s less flushing and cleaning involved. Because plant roots aren’t installed in a growing medium, they are generally easier to inspect, manage and remove, if necessary.

It’s even possible to change from one type of system to another during the process. Aeroponic systems are also easier to relocate than other types of indoor gardens. They’re lightweight, which makes them user-friendly.

Space savings: By some accounts, growing a crop aeroponically uses as little as one-tenth of the space of growing that same crop in soil.

Practically speaking, there are definite space savings, but how much space will depend on a few factors.

You can produce plenty of clones and seedlings aeroponically, but growing a tomato plant to maturity will still take some room. It is easy to grow plants vertically using aeroponics, though, which can be a big space-saver depending on your crop wish list and layout.

A-frame units are popular, especially for crops like herbs and salad greens.

Water savings: Some crops require a lot of water, and the prospect of saving nearly half on water consumption (40% or thereabouts) using aeroponics can be pretty compelling.

Cost savings: Because aeroponic systems use less water, fertilizer and space than other plant-growing options, they incur lower operating costs over time.

Disadvantages of Aeroponics

Higher initial costs: In theory, aeroponics is elegantly simple, but growing plants with air, water and nutrients can be intensive when it comes to getting the necessary equipment.

Why? Because timed nutrient availability is an essential part of the process. It requires automation tools and the ability to produce a fine mist under adequate pressure.

Aeroponic assemblies use pumps, prefilters, manifolds, fine spray nozzles and timers, not to mention the lights, fans and other accessories associated with indoor growing.

Unless you’re an avid do-it-yourselfer and can build your own system, start-up costs are high compared to other indoor growing options.

If you do take the DIY route, be sure to steer clear of PVC materials, which can leach dangerous chemicals, and stick with food-grade pumps, nozzles, tubing, and fittings.

Malfunctions can be deadly. Because plants depend on regularly supplied nutrients and moisture, anything that upsets that delicate balance can spell disaster, including power outages, blocked sprinkler heads, wonky timers, kinked hoses, and clogged filters.

Not all aeroponic systems are created equal: There are lots of different ways to construct an aeroponic system. But the most critical task is to ensure regular, fine-mist nutrient delivery. This can be harder than it sounds.

From design problems like voids that don’t get enough, or any, spray, to low-pressure systems that fail to deliver nutrients efficiently as plant roots become more dense and crowded, this is one area where close monitoring is important.

The old adage, “You get what you pay for,” is true here as well.

There’s a learning curve: From deciding on the best plant cultivars to choosing the right nutrient brand, timing schedule, and mist droplet size, a successful aeroponic set-up requires experimentation.

If you haven’t done it before, it’s a whole new approach to gardening. The error part can be frustrating, especially in the beginning. With careful research and planning, you can avoid potential problems and recognize others early on before they become critical.

The technology is still developing: Aeroponic technology, although robust, may not be as focused on the casual indoor grower as one might expect looking at all the advancements in hydroponics over, say, the last 10 years.

Read: Pros and Cons of Hydroponic Gardening

Demand hasn’t caused the downward price adjustments and entry-level bargains one sometimes sees with hydroponics, either. There’s a great deal of interest on both the developmental and the retail side of the equation, though, which means more and better (and possibly more budget-friendly) ways to garden aeroponically in the future, so stay tuned.

The Future of Aeroponics

Using air to produce a great indoor garden isn’t the only thing on offer with aeroponics. Some experts believe it’s the wave of the future for locavores and urban farmers, especially in areas where land is precious and there are plenty of mouths to feed.

If you’ve seen those futuristic photos of green landscapes growing up the sides of skyscrapers, you’ve got the idea.

It’s also interesting to note that aeroponics is important to the space program, where NASA is hard at work planning ways to grow crops efficiently during manned space travel or wherever humans might land in the future, including the moon and Mars.

Until we start adding a planet prefix to our zip codes, though, aeroponics can be a powerful and effective tool for the indoor gardener right here on Earth.

Read next: Fogponics - A New Spin on Aeroponic Gardens