Homegrown lettuce in the dead of winter or the heat of late summer? It’s possible with hydroponics. And you don’t need a fancy setup with electric pumps and a water circulation system. The Kratky method lets you do it with a grow light and an empty coffee bin.
Developed by horticulturist Bernard A. Kratky of the University of Hawaii at Manoa, the Kratky method is ridiculously simple. Plant roots need access to oxygen. When grown outdoors, a plant’s roots find this oxygen in air pockets within the ground. In a commercial hydroponic system, pumps circulate air to the plants’ roots. In the Kratky method, an air pocket is formed as the roots take up water, lowering the water level. This air pocket provides all the oxygen a plant needs at the root level.
It’s well known that atmospheric carbon dioxide (CO2) is one of the leading causes of climate change and that plants play a role in mitigating its impact by taking in carbon dioxide and releasing oxygen. But did you know that even the smallest gardens can make a difference? Container gardens can be effective ways for adding plants to the ecosystem, nurturing pollinators and other beneficial insects, and even providing food for your table.
High above Columbia’s Wilde Lake at the Residences at Vantage Point, long-time gardener Barbara Schuyler continues the gardening that was her passion when she and her wife Pat Wilson lived on a rural property. More than 90 containers of shrubs, annuals, perennials, and vegetables grace two balconies that face west and south.
Barbara’s approach to container gardening
Shrubs and perennials comprise a significant part of the garden. Hardy perennials winter over and are especially effective at drawing down carbon dioxide. Some of the perennials, like the orange butterfly milkweed (Asclepias tuberosa) pictured below, are natives. Native plants are well-suited to our climate, require less care than imported species, and support native insects. Barbara’s native plants also include lots of Rudbeckia, some Echinacea, and several Heuchera.
In addition, each year Barbara and Pat decide on a theme and collect annual seeds to plant when the temperature warms up each spring. Last year, the blue flower theme provided a consistent backdrop for the foliage and flowers of other plants.
She uses regular potting soil and each spring spreads the old soil on a tarp to remove roots and debris and returns it to the pots with a portion of fresh potting soil added.
Her collection of containers is eclectic and includes salad tables for vegetables, wine barrels, ceramic and plastic pots. A container exchange in the building helps many patio gardeners find pots that meet specific size and decorative needs. Reusing and sharing materials can help reduce CO2 associated with buying and shipping new products. She also tried felt bags but was not pleased with the results.
Watering 90 containers with a watering can during dry spells would be a major challenge, so Barbara purchased a garden hose sink adapter to allow her to connect a lightweight flexible hose to the kitchen sink.
One big advantage of balcony gardens is that deer can’t get to them, though she has seen a squirrel or two.
Visiting her garden every morning is a joy in itself. It provides Barbara the opportunity to be present with her plants, be aware of their needs, and appreciate what they offer throughout the seasons.
Even at this extreme height, pollinators are attracted to and supported by the garden. Three species of bees, several types of moths, and even a few monarchs have been spotted.
Lettuce and arugula do well in pots, and along with cherry tomatoes provide healthy super-local produce — yet another reduction in their carbon footprint. One lesson Barbara’s learned about cherry tomatoes is not to crowd them. Plant just one to a large pot and prune assertively to be sure the energy goes into making tomatoes rather than excess foliage and that there’s sufficient air circulation.
While there’s some level of physical work involved, container gardening is within the reach of nearly everyone – no matter your available space, skill level, physical abilities, or budget. Start small. Share stories, plants, and pots with other gardeners, and enjoy the benefits for yourself, your community, and the planet!