Understanding Climate Zones

Different plants like different climates. Artichokes like mild weather year round. Okra loves heat and humidity. Apples and plums need a certain number of hours of winter chill to fruit well. To help gardeners know which plants perform best in which areas, the USDA created a map of climate zones, assigning each zone a number. Once you know the number for your area, all you need to do is look for that same number on the label when you shop for plants.

Unfortunately, these zone maps aren’t any guarantee that the plant you choose is actually suited to your area for a couple of reasons:

  • It doesn’t account for microclimates—variations from the standard climate of the area caused by terrain, construction, vegetation and other variables. Concrete, for example, collects and retains heat, raising the ambient temperature of the surrounding area, while dense trees keep the ground cooler than usual by preventing sunlight from reaching the ground. Microclimates can even vary within a single yard. A sunny wall in an enclosed backyard can be almost a full number higher than a shady, open area at the front of the house.
  • It focuses on lows and largely ignores highs. Just because a plant can’t take freezing weather doesn’t mean it can handle scorching heat. Take for example the artichoke, mentioned earlier. It loves the temperate Northern California coastal marine zone for its fog and even, year-round 50-60 degree temperatures but may not be happy at all in Austin Texas or the Florida panhandle (all zone 8b).
  • Climates change. The current map, which was last updated in 1990, no longer accurately reflects the current climate trends. Thankfully, they are currently in the process of updating the map, but that won’t really help the plants you already have in place.

One other thing to consider, plenty of plants, given the right placement and attention, can survive outside their zone. The trick is make sure all of their other needs (sun, water, etc.) are being met and that you’ve placed them in an area of the yard with a microclimate that comes as close as possibly to their preferred zone.

Find Your Zone

NOTE: If you live in the Western United States, check out the Sunset Western Garden Book which has its own zone system designed to account for the extremely varied climates of this area.

Choosing Containers

There are so many great things about container gardening. For starters, they fit just about anywhere from a tiny apartment windowsill to a sweeping multi-acre estate. They let you garden where you couldn’t otherwise—on a 5th story balcony, inside an office building, on land that’s soil has been damaged by toxins or overuse. They allow you to move plants around as your moods (or the weather) dictate. And most fun of all, containers come in a wide variety of sizes, styles and materials to suit your personality, architecture and budget.

Here is the low-down on some of the most common container types:

Terra Cotta
Probably what most people think of when they think of planting in pots, terra cotta has been around since ancient times. The signature orange unglazed pottery tends to build a mossy coating over time making it especially well-suited to English country gardens.

Pro: Inexpensive, available most everywhere in a variety of sizes, very well draining, easy and fun to decorate (use non-toxic paints as terra cotta is porous and any chemicals could leach through to your plants)
Con: Heavy, dries out very quickly, susceptible to cracking at freezing temperatures, easy to break

To help terra cotta retain water more efficiently, consider using it as a liner for another decorative pot.

Ceramic

Ceramic pots are a great way to add color to your garden. These days they come in a wide variety of patterns, shapes and hues. Try a bold red accent in an Asian-themed garden, or a rich gold for a Tuscan feel. Make sure they have drainage holes unless you plant to use them for a water garden.

Pro: Retains water well, lots of variety in size, shape, color and design,
Con: Often very expensive, especially in larger sizes, extremely heavy, can shatter in below-freezing temperatures

Cast Concrete
These planters can give an instant old-world feel to any garden, especially when overflowing with ivy or other tumbling vines. Consider adding a single, clean-lined focal piece for a bold modern statement, or flank an entryway with two more traditional containers for a classic look.

Pro: Strong design statement, ages beautifully, hard to damage
Con: Extremely heavy, often expensive, can be affected by severe weather, can break down over time

Because concrete can break down over time and because some concrete products may contain harmful chemicals, make sure it is coated inside and out with a non-toxic sealant.

Wood
From redwood planters on the patio, to a recycled wine barrel full of veggies, wood ads a warm, natural look to any landscape. Because wood is readily available, simple to work with and often inexpensive, you can easily build your own pots to suit your tastes and space.

Pro: Natural, not harmed by cold
Con: Decompose over time, can invite termites if placed directly on soil

If you’re going to place a wine barrel or other wooden planter directly in a planting bed, be sure to place it on brick or cement blocks to prevent contact with the soil.

Plastic

You used to only be able to get plastic pots in a terra cotta color and forest green, but things have changed a lot since those days. Now you can find just about any color, size and shape you can imagine, including pots made to look and feel like ceramic, terra cotta, cast concrete and even wood without all the weight and with a lot more resistance to cold and rot. With so much variety, you can find a plastic container for just about any style of garden you can dream up. Plastic pots are especially well suited for balcony and rooftops gardens where load-bearing may be an issue.

Pro: Lightweight, weather-resistant, retains water well, huge variety in color, size, style and price, work well as liners for other pots
Con: Can tip when planted with top-heavy trees, can be expensive for the more elaborate designs, inexpensive or thin-walled pots can break down or fade with prolonged sun exposure

Use caution when planting trees in plastic pots in high-wind areas, as they can be blown or tipped over fairly easily. Consider securing the tree to a nearby structure where wind is a problem.

Nursery Pots
A subset of the plastic category, nursery pots are the black, terra cotta or green pots that most plants are sold in. While they are not particularly attractive, most gardeners usually have a few lying around in a variety of sizes making them easy to get for little or no money, so if you’re on a budget they can be a great solution.

Pro: Inexpensive or free, lightweight, weather-resistant, retains water well, work well as liners for other pots
Con: Unattractive, can tip when planted with top-heavy trees

Nursery pots are best used as liners for other pots or in places where they can be hidden by foliage.

Every Day Objects
Just about anything that won’t rot when wet and can be drilled for drainage can be used to hold a plant, so get creative. Here are just a few ideas to get you started.

  • Metal trash cans
  • Buckets
  • Pedestal sinks
  • Claw foot tubs
  • Tea pots
  • Rubber boots
  • Empty paint cans (be sure the paint is completely removed)
  • Antique wash basins
  • Get creative!

If you’re going to be growing food plants, make sure your container doesn’t contain toxic materials (lead paint or glaze, for example). If you’re not sure, use a nursery pot as a liner to protect your plant (and your pot).

Forget Me Not Farm (Sonoma County, CA)

“Since its inception in 1992, Forget Me Not Farm has helped thousands of at-risk children and youth break the cycle of abuse. Located on the grounds of the Humane Society & SPCA of Sonoma County, the Farm offers animal-assisted and horticultural therapeutic activities that provide a haven for children, plants and animals to bond, learn and heal with one another.”

On the farm the children interact with animals, grow flowers, fruits and vegetables from seed, harvest the plants they helped cultivate and even cook with the ingredients they grew. The farm experience gives them a safe, non-threatening environment to heal while teaching them valuable skills. Excess produce is donated to local shelters, extending their reach even farther into the community.

Hidden Villa (Los Altos, CA)

Hidden Villa is a nonprofit educational organization that uses its organic farm, wilderness, and community to teach and provide opportunities to learn about the environment and social justice. Hidden Villa stretches over 1600 acres of open space in the foothills of the Santa Cruz Mountains, about 40 miles south of San Francisco. Our mission is to inspire a just and sustainable future through our programs, land and legacy.”

Hidden Villa is also a working farm, complete with a Community Sponsored Agriculture program. A portion of all harvest go to shareholders, while another is donated to local low-income families.

As part of their educational programs, they offer a large assortment of family-oriented classes and events (including How Does Your Garden Grow?, Cheese Please! and my personal favorite, Manure to Meadow to MMMMmmm!) all at very reasonable prices.

Like most non-profits, Hidden Villa is run by a very limited full-time staff on an even more limited budget (especially now), so they rely very heavily on their hundreds of volunteers to keep things running.

I spent a day volunteering as a horticulture worker, starting shrub cuttings and labeling fruit tree scions while others in the group hacked back overgrown blackberries or mulched garden beds. After, we got a tour of the grounds. For me, at least, the rewards of helping to start new plants alone would have been enough, but knowing it was for a good cause made it even better.

If you live in the San Francisco Bay Area, consider volunteering.

Gardening Classes & Programs

You don’t need a college degree to become a great gardener, but taking a class or two can not only help improve your gardening knowledge and skills, it can also be a great way to meet fellow gardeners in your area. Many park and rec departments offer classes on gardening, composting and other related topics, as do local community colleges and many garden centers.

If you want to dig deeper, there are a variety of programs available through universities, colleges and specialized educational centers. Here are just a few to get you started.

California
Occidental Arts & Ecology Center, permaculture and ecological design
Sonoma State University Extension, Sustainable Landscape Certificate

New Mexico
Permaculture Institute, courses offered in various locations