phenolic foam brick

I just moved into an apartment that has a 9-by-7-foot balcony. When I lived in a house, I planted tomatoes and corn every year, but now what can I plant in that small balcony? Could I plant lavender there? The balcony receives morning sun.
>Elba Rivera, Montrose
Believe it or not, you may be able to plant not only lavender, but corn and tomatoes as well.
Fourteen years ago in this column, I wrote about Isaiah Yagil, an Israeli horticulturist who grew beefsteak tomatoes, yellow chili peppers and 7-foot sunflowers, hydroponically, on a sun-splashed patio in Northridge.
Yagil’s technique relied on floral bricks made from phenolic foam, that familiar green and spongy material which, placed at the bottom of a vase, is used for holding the stems of cut flowers.
Yagil, who worked for the Jet Propulsion Laboratory in Pasadena, believed that his floral brick growing technique could be used in a space station, where room for growing plants is limited. Each of Yagil’s plants requires only 1 square foot of growing space.
Yagil’s method results in incredibly rapid growth. A 4-inch tomato seedling, for example, can grow into a 4-foot tall, fruit-laden specimen in only 60 days.
To grow any plant according to this technique, you will need to take a 3-by-4-by-9-inch floral brick. Remove a plug from one of its short ends that is equal in size to the root ball of the seedling you wish to plant. A seedling that has produced two to four leaves — available at the nursery in six- or eight-packs — is perfect.
Wrap the brick, except for the bottom end, in black plastic and secure it with strapping tape. Stand the brick up in a 1-gallon (6-inch diameter) plastic container — the kind you get when you buy a 1-gallon plant at the nursery — with holes in the bottom. Keep the brick stable by running pieces of strapping tape up one side of the container, across the brick, and down the other side.
Place a deep, water-retaining dish under the container. Keep the brick wet by filling the dish. The dish is filled as soon as the water in it evaporates, as often as once a day in summer. Liquid fertilizer is added to the water every third time the dish is filled.
Water moves up the brick by capillary action, the same way it moves through the soil, until it reaches the seedling roots. Since water is always available, the roots do not need to grow much and the plant’s energy is devoted almost entirely to top growth. That is why plants grown by hydroponic or soil-less techniques such as this develop more quickly than plants grown in the ground.
In the dry climate where we live, a plant must focus much of its resources on finding water. When it is freed from that burden through hydroponics, a plant can turn nearly all of its energy into leaf, flower and fruit production.
Getting back to your balcony: You will have to rotate your containers, no matter whether they contain phenolic bricks and water or just ordinary soil, a quarter turn every few days so that each side of the plant receives the same amount of sun. Otherwise, you will see flowers and fruit on one side of the plant only.
That being said, most plants in Southern California, due to our intense summer heat, do best with a morning sun exposure, so your balcony location should be hospitable to just about anything you want to grow, from gardenias to roses to petunias to lavender.
Tip of the week
I want to thank Sharon Klek of Granada Hills for bringing summer snowflake (Leucojum aestivum) to my attention. This bulbous plant is misnamed, since it blooms at the same time as daffodil, to which it is related, in late winter and early spring. Summer snowflake is as tough a plant as you will find, growing in every type of soil, even when waterlogged. Flowers are small white bells with a green dot on the edge of each petal.