Rooftop Garden — Spring Equinox Report
This year, the onset of Daylight Savings Time coincided with 5 days of warm, spring-like weather around here, causing crocuses to pop up and sunny optimism all around. Although in reality we’ve got a long way to go yet, the ground is starting to thaw and the earthworms will be coming up soon. Up on the roof here at the restaurant things are definitely beginning to happen, and now is the time to get started on the new spring season. Even though I’ve maintained a container garden on the roof ever since we opened in 2005, this year things are clearly different and better.
A little background and history: early experiments with various herbs and vegetables led me to focus almost exclusively on growing herbs for use in our kitchen. I’m lucky to occupy a one-story building with a flat roof, and access in easy (if you don’t mind steep ladders!). In spite of our urban setting, Cambridge’s low scale allows us abundant broad daylight and plenty of direct sunlight up there. The garden is built entirely of readily available recycled materials: bean crates and bushel baskets from our vegetable suppliers that are lined with slats cut from cardboard boxes from other deliveries, filled with dirt and organic compost provided by some of our farmer friends. The natural irrigation system during the summer season comes from the condensed water that drips from the large air-conditioning units on the roof as it puddles and meanders in a slow river across the roof to the gutter; I simply place the containers in the way of this river and the plant roots are able to “capillate” according to their needs through the slats in the crates and cardboard. Amazingly, between the drip irrigation, periodic rains and captured rainwater, there’s no need to use the garden hose ever between Memorial Day and Labor Day all throughout the height of the growing season — not even one single time!
I’ve done plenty of little experiments over the years: tomatoes, etc. But vegetables have too many specific requirements — soils variations, sunshine and water. But herbs are generally a bit more tolerant and forgiving, and I stand a much better chance with them of coming closer to obtaining yields that can actually supply our needs here at the restaurant. The best successes I’ve had in this department: hot chilies for use in our ceviche and French breakfast radishes for our vegetable antipasto.
The usual members of this culinary herb garden include: rosemary, thyme, sage, wild marjoram, parsley, lovage, cilantro, basil, purslane, mint and chives. Several of these herbs are perennials that survive the harsh New England winters in their frozen containers and come back to life each spring in amazing fashion. I divide the roots of the chives and mint every new growing season and have doubled the number of these plants each of the last couple of years. The thyme, sage and lovage struggle in this setting and have had mixed results in bouncing back. The rest are annuals that I purchase from catalogs or from an herb farm at the Central Square Farmers’ Market and plant new each summer. In all, I had 35 containers of herbs up on the roof last summer.
The rosemary bushes are my special pride and joy, and I have 14 of them. They require the most work for me to keep them alive throughout the year, but they’re worth it! The last couple of years, I’ve moved them down from the roof to inside the restaurant during the winter months — we’re also very lucky to have the big glass atrium that provides lots of daylight inside throughout the winter. But now after several years they’re getting just too big and heavy to carry around.
To solve this problem — and to get back to the subject of why this year is different and better — last fall I built a cold-frame on the roof out of cedar lumber and old windows (from an architectural salvage warehouse in New Bedford) to house these large plants and keep them warm (enough) to survive the frigid cold of winter here in New England. My strategy worked! The rosemary bushes survived; they didn’t love it, but they were protected and they got just enough warmth (roof vent from the restaurant’s bathrooms!) and sunlight from December through March to make it. During the rare occasions that we would get a break in temperature and some relatively warm rain, I could hop up there and remove the windows for them to soak it up. And now with the warmer weather and increased daylight they are starting to take off again, well ahead of their usual spring schedule!
In addition to the cold-frame, I also built a large compost bin on the roof last fall and started making more of my own dirt. This is also home to my earthworm collection, at this point now numbering somewhere between 2000-3000 by my most recent calculations.
Now that the cold-frame has served it’s purpose for the rosemary plants, I’m ready to use it to start seedlings for this year’s garden. The chives have started growing already in there, and in April they’ll be followed by other herb seedlings that I recently purchased (ahead of the growing cycle for this zone) from an online organic supplier. It’s only the end of March here in New England, and my urban rooftop garden is already well ahead of schedule in 2010 — it’s going to be a fantastic year!