When coffee klatches were held a generation ago, people didn’t leave with Tupperware but with home planters, nutrient solutions and something that looked suspiciously like pea gravel.
Several of those planters might still be taking up space in a corner of the basement, one of them providing a home for what is now a venerable jade plant-a gnarled specimen that, despite the lack of soil, has managed to survive quite nicely.
That system of growing without soil has been around since the Hanging Gardens of Babylon and is gaining more credibility in agricultural applications as the world searches for ways to produce enough food while not destroying the planet.
Today it’s called “hydroponics”-the science of growing plants without soil. By supplying the proper nutrients at the proper time using air spacing rather than traditional soil, the plant grows faster and the root mass does not have to be as extensive because all the plant’s needs are met regularly.
This is an entire science, and it can get confusing, so let’s simplify it right down to our jade plant’s basics.
What can be grown?
“The biggest question I get from customers is `What can I grow hydroponically?’ ” says Clarence Bares, owner of Heartland Hydroponics in Vernon Hills. “I tell them it depends on how much light you want to spend money on.
“Indoors, the best plants for growing hydroponically are those that are short, so they will stay close to the light source. Basil is good, as is lettuce. Tomatoes are not too bad if you get a determinate variety that is not too tall.”
Other candidates for hydroponic growing include African violets, orchids, geraniums and other herbs and vegetables. The decision each gardener has to face is whether the growing is a maintenance function, such as the jade plant, or a rapid growth situation such as winter vegetables or flowering plants.
Seeing the light
“Without the light, you have nothing,” is the way Gary Grendel, owner of Greenfield’s Hydroponics and Indoor Garden Equipment in Niles, summarizes the need to provide adequate illumination for the plants. The sun can’t be counted on in January-neither its intensity nor its availability. Even in a greenhouse, light-loving plants need supplemental illumination.
Fluorescent fixtures have been the traditional source of supplemental lighting for indoor plants but super-bright bulbs and reflectors are rapidly replacing fluorescents in many hobby plant-growing setups. Called high-intensity discharge lights, these energy-efficient fixtures produce more of the daylight-spectrum rays that plants seek, and are available in an eye-pleasing white-blue (metal halide) for most growing purposes, and a yellow-orange hue (high pressure sodium) that enhances flowering response.
Many of these fixtures are square-shaped and can be attached to a track that moves the light back and forth to evenly illuminate a bench setup. Another option is an arm mechanism that rotates two lights in a circle to light an entire tabletop or roomful of plants. Prices start at about $140.
Types of systems
While many hydroponic systems are one step removed from a commercial greenhouse-utilitarian, functional and not attractive-others are pre-packaged systems that look at home in the most formal living room. The growing mediums also span the spartan-to-decorative range. Here’s a rundown on what’s available:
– Passive system. Our jade plant is an example of a passive system. Water is poured through the stone, collects in a basin under the pot and is wicked by the roots back into the root zone to provide the plant’s growth.
“Straight wick systems are based on capillary action, which is good for slower-growing plants such as indoor plants that are in a maintenance mode versus a growth mode,” says Peter Wardenburg, vice president and general manager of Hydrofarm Gardening Products of San Rafael, Calif. “There is no need for a pump and timer for that dracaena sitting on your desk. If you want to grow a tomato plant, it will grow much more slowly in a capillary pot versus (a drip system) where it will grow a couple of inches a day.”
– Aerated nutrient solutions. To make our jade grow faster, we could aerate the nutrient solution from which the roots are feeding. Wardenburg’s company sells a kit-basically a tray with pots sitting in it-that uses an aquarium-type bubbler to achieve this principle.
Called “Emily’s Garden,” the plants grow in pebbles, called expanded clay or lightweight aggregate, that provide air spacing around the roots. “This is the basic hobby system, the most forgiving while still using the productive, clean hydroponic system,” Wardenburg says. “If the plant has wet feet sitting in water, it will drown, but if you are aerating the solution, you are accelerating productivity.”
The Power Grower, a system that combines technologies, has a bubbler that creates pressure in the water reservoir, pushing it up a tube to a drip ring that surrounds the plant. The oxygenated solution drips on the aggregate planting medium and drains back into the reservoir.
– Ebb and flow. “Ebb and flow is a simple system of automated flood and drain cycles. A timer turns on a pump that floods a tray. When the timer turns off the pump, the tray drains,” says David Ittel, owner of Chicago Indoor Garden Supply in Streamwood. A typical setup would send the nutrient solution into the plants’ root zones three times a day, allowing the air to penetrate as the roots dry. It is the next step in efficiency from aerated nutrient solution growing.
Hydrofarm’s system uses trays with ribbed bottoms, and is designed so pots containing different planting mediums can be grown side-by-side. “We’ve had orchids in bark set in the system next to plants growing in soil mix,” says Wardenburg. “You do have to grow plants that have fairly similar cultural conditions.”
– Drip irrigation.”Again you have a reservoir with a pump and a timer, which pushes the solution through tubes to emitters that drip the nutrient at the base of each plant,” Ittel says. Cucumbers, tomatoes and peppers are grown this way commercially.
“Rock wool is the most commonly used growing medium, or perlite, but people are experimenting with all kinds of mediums, even coconut husks.”
The advantage of drip systems is the accuracy with which the nutrient is delivered directly to the root zones. As the old nutrient flows out of the bottom to the reservoir tank, it takes the stale air with it; the top watering allows fresh air to enter the growth system.
To provide the trace elements that are left out of regular fertilizers, special formulations are used in hydroponics. A typical shopper at Ittel’s store is confronted with several types from each manufacturer. He explains that certain chemicals precipitate out if they are included in one formulation, so two solutions typically are combined-in ratios determined by the type of plant being grown-to get the right combination that is then diluted for use.
Although Ittel prefers liquid concentrates, powdered formulas also are available that are then dissolved to make the nutrient solution. Both organic and inorganic compounds are available.
Once the basics have been mastered, the gardener can explore some of the more complex areas of hydroponics. A sampling of articles in the Growing Edge magazine includes “Phenolic (Floral) Brick as a Hydroponic Medium,” “Mutation Breeding-Do-it-Yourself Mutants,” and “More Oxygen for Your NFT.”
Or do as David Ittel does: Grow your own chili peppers all winter. He can’t live without them, he says.
For more information, you can contact:
Greenfield’s Hydroponics and Indoor Garden Equipment, 8139 Milwaukee Ave., Niles, Ill., 60648. 708-965-5056. Free catalog.
Chicago Indoor Garden Supply, 297 N. Barrington Rd., Streamwood, Ill., 60107. 708-885-8282.
Heartland Hydroponics, 115 Townline Rd., Vernon Hills, Ill. 60061. Free catalog. 708-816-4769.
Hydrofarm Gardening Products, 4967 N. High St., Columbus, Ohio 43214. Free catalog. 1-800-833-6868.
