By Mary Ann Steele, Somervell County Master Gardener
Crop rotation is like playing a long term game of musical chairs in the garden. Every plant is different: inviting specific pests and diseases and demanding more of nutrients than others. Growing the same crop in the same spot year after year drains the soil, and can lead to sick plants. To make matters worse, some diseases and pests can end up taking residence in the soil around the plants they prey on most. Keeping those plants in the same place is like inviting pests to an “all-you-can-eat” restaurant where their favorite meal is served every day.
Keeping a record of each crop allows you to perform the old switcharoo, confusing pests and diseases, and giving the soil a chance to catch up on depleted nutrients. As a general rule, replacing a crop with a member of a different family will make a big difference.
Plant light feeders with heavy feeders, and deep-rooted plants with shallow-rooted plants. Deep-rooted plants dig up the soil and bring nutrients from way below up to the top, while shallow-rooted crops create a web of roots near the surface, preventing erosion.
Some insect pests are put off by the smell or chemical composition of certain plants. Protect vulnerable plants by growing repellent plants nearby. Surrounding a vulnerable plant with something strong-smelling, like onion or garlic, can confuse pests. Try marigolds, garlic chives, lavender or mint.
Insect pests are known to prefer some plants over others. Try growing a known pest magnet near your favorite crop as a decoy. Once infected, remove the decoy and destroy it, pests and all. Try nasturtiums, mustard greens, or marigolds.
Legumes, such as beans and peas, can convert nitrogen from the air and release it into the soil. Follow legumes with nitrogen-loving brassicas, such as broccoli, cabbage, or kale.
Grow tall, sturdy plants in front of delicate and sensitive crops as a protective shield against wind or excessive heat.
Grow short, quick-growing, shallow-rooted plants such as lettuce and greens under tall, leafy plants like tomatoes or okra. The short plants will shade the soil surface for the tall plants while they work to get established, and the tall plants will provide shade for the short plants later in the season when the summer gets hot. Try leafy greens, lettuce, parsley, and thyme.