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Crop Rotation

Posted: May 3, 2011

“We’ve been raising sweet corn on our lot for three years now. We started out with good harvests, but this year the cornstalks are spindly and not producing well. Plus, we’re seeing more insect damage. What do you think is happening?” The questioners, now in their fourth year of growing the same crop on the same plot, were learning the hard way about the importance of crop rotation.
Kale is a hardy cool-season cole crop.

Kale is a hardy cool-season cole crop.

Growing the same crop in the same place depletes the soil of the same nutrients. It also can leave traces of disease ready and waiting to strike the crop next year. Plus, insect pests don’t even need to look for their favorite treat—it’s right there where they’ve feasted and reproduced.

Crop rotation not only avoids these problems, it can also enhance productivity, because one crop can add nutrients to the soil needed by next year’s different crop. Some crops also improve soil structure and deter weeds.

At its simplest level, crop rotation means not growing the same crop in the same spot each year. Even more effective crop rotation relies on rotating plant families from year to year. The major plant families in most vegetable gardens include the solanaceous (tomatoes, potatoes, peppers, eggplants), cucurbits (squashes, pumpkins, cucumbers, melons), legumes (beans, peas), and cole crops (cabbage, broccoli, kale, cauliflower). For the purposes of simplifying rotation, corn can be included with the cucurbits, and lettuces with the cole crops.

First, identify by family the crops you wish to plant, then divide your garden into a  section for each family. If you wish to plant members of each family, for example, you will need four sections. Plant a different family in each section and record a map of your plantings in your garden log. Next year, rotate the families to a different section, and so on, for four years.

What about crops such as carrots, beets, radishes, and onions? They may be planted among any group and can also be used in succession planting when any plant is removed. The same can be said for companion plants used to reduce pesticide use.

For those wishing to know more, Penn State Extension offers information sheets featuring helpful charts and suggestions. Shepherd Ogden’s Step by Step Organic Vegetable Gardening provides even more detailed guidance.

What about crops such as carrots, beets, radishes, and onions? They may be planted among any group and can also be used in succession planting when any plant is removed. The same can be said for companion plants used to reduce pesticide use.

For those wishing to know more, Penn State Extension offers information sheets featuring helpful charts and suggestions. Shepherd Ogden’s Step by Step Organic Vegetable Gardening provides even more detailed guidance.