Vegetable Gardening (12 page)

One category generally available only to commercial farmers is that of the
genetically modified variety.
This kind of plant has a gene from a completely unrelated species inserted into it so that it exhibits a certain trait. For example, geneticists have inserted a gene of the biological pesticide Bt (see Chapter 17) into potatoes so that when the Colorado potato beetle (their biggest enemy) eats a potato's leaves, it also eats the pesticide and dies. Many questions exist about the long-term health risks and environmental safety of manipulating the gene pool so dramatically and quickly. For this reason, genetically modified organisms (GMOs) aren't allowed in organic gardening.

Timing Your Planting Wisely

As my dad used to say, "Timing is everything." This axiom is especially important for vegetable gardening, so file it where you can't forget it. Remembering it will save you lots of heartache and disappointment. For example, if you plant tomatoes too early, the plants will sit there like bumps on a log, not growing and possibly rotting in cold, wet soil or turning mushy and black after they've been zapped by frost. Plant lettuce too late, and it'll produce more flowers than leaves, and the leaves you harvest will be tough and bitter. I can give you examples like this for every vegetable, but I'll spare you the monotony. Just know that planting at the wrong time of year is a recipe for disaster.

If you follow the rhythms of nature and plant when conditions are perfect for proper growth, growing vegetables is a breeze. But how are you supposed to know about these rhythms? Start tapping your foot, because the following sections will have you moving like Fred Astaire.

Some like it cool, some like it hot

Vegetables can be divided into the following two categories based on the temperature conditions in which they grow best:

Cool-season vegetables:
These vegetables, such as lettuce, spinach, peas, potatoes, broccoli, and cabbage, grow best in the cool weather of spring and fall. As vegetables go, they're fairly hardy and survive despite freezing temperatures. In most areas, cool-season vegetables are usually planted in early spring so they mature before the onset of hot weather, or in late summer to early fall for maturation in the cool months of fall or early winter. However, in areas where summers are very cool and winters are mild, such as in coastal areas of the western United States and the far north, cool season vegetables can be grown year-round and may be the only vegetables that can thrive in this climate.

What happens if you plant a cool-season vegetable when it's too warm? Not a lot of good. Lettuce will
bolt,
meaning it starts to flower before you get a chance to harvest it. In other words, instead of producing tender, crisp leaves, lettuce will send out a tall flower spike. Any leaves that are left on the plant will be bitter-tasting and tough. Broccoli will form loose clusters of yellow flowers instead of forming nice tight heads. And peas won't properly fill their pods with sweet, succulent peas. You get the idea!

Warm-season vegetables:
These vegetables, such as beans, tomatoes, peppers, cucumbers, melons, squash, okra, and corn, like it hot and grow best in the warm months of summer. They need warm soil and air temperatures to grow their best; if they're planted while the weather is still too cool, they'll suffer and not grow. Because freezing temperatures kill these vegetables, they're usually planted after the threat of frost in spring. In warm areas, they also can be planted in late summer for a fall harvest.

To push along warm-season veggies, wait until the soil and air are the proper temperature. Or consider using season extenders to trap heat around the plants. Season extenders also help in cool summer climates such as the Pacific Northwest, where the weather rarely gets warm enough even in summer to ripen heat-loving vegetables like melons. (Chapter 21 has more ideas on season-extending techniques.)

Frost dates and the length of the growing season

You should know two very important weather dates for your area if you want to grow vegetables successfully:

The average date of the last frost in spring

The average date of the first frost in fall

These frost dates tell you several important things:

When to plant:
Cool-season vegetables are generally planted 4 to 6 weeks before the last spring frost. Fall planting of cool-season vegetables is less dependent on frost dates, but it's usually done 8 to 12 weeks before the first fall frost. Warm-season vegetables are planted after the last spring frost or in late summer in warm areas for a fall harvest.

When to protect warm-season vegetables:
Frosts kill warm-season vege-tables. So the closer you plant to the last frost of spring, the more important it is to protect plants. And as the fall frost gets closer, so does the end of your summer vegetable season — unless, of course, you protect your plants. I show you how to provide frost protection in Chapter 21.

The length of your growing season:
Your
growing season
is the number of days between the average date of the last frost in spring and the average date of the first frost in fall. The length of the growing season can range from less than 100 days in northern or cold winter climates to 365 days in frost-free southern climes. Many warm-season vegetables need long, warm growing seasons to properly mature, so they're difficult, if not impossible, to grow where growing seasons are short.