"Nurseries are perfectly fine, too, for buying seeds," he notes. "If you're buying an F1 hybrid and all the companies are selling it, it's exactly the same plant. If it's an open pollinated or heirloom plant, the seed quality could be variable so you want to buy from a reputable source. Then check to see that the packet provides essential information, that the seeds are disease resistant and that the package is easy to reseal if you don't use all the seeds."

Depending on where you live, you may need to adjust the amount of pH to get it just right for your crops. Most vegetables require a pH of between 6.0 and 6.8. Your local extension office can help you with advice on testing and improving your soil.

Some crops do fine in early spring before the last frost. These hardy veggies include beets, carrots, parsnips, peas, radishes and Swiss chard, as well as many salad greens. After the last frost, beans, corn, squash and many herbs can be planted by seed. The most tender of plants — cantaloupe, okra, lima beans, peppers, eggplant and tomatoes — prefer the warmest, sunniest and driest spot in the garden, and should be planted when soil has warmed to at least 60 degrees. Your fall garden can yield broccoli, kale, spinach and turnips well past frost.

Paul suggests staggering planting to make your harvest longer. He uses lettuce as an example. "Plant one row of lettuce, then another one the next week," he explains. "Keep going as long as your season allows so that you're not inundated with, say, four rows of lettuce ripening all at once. That works well with carrots and beans too." After an early crop is harvested, plant a summer one in its place.