WHAT IS CROP ROTATION AND WHY DO IT?
Crop rotation, that is rotating the position of your crop “families” from year to year, is one of the simplest ways to control many insects, weeds, and diseases in the garden. Crop rotation does two things for the garden: It improves soil and controls diseases. Because crop rotation enhances soil fertility, you will find an increase in crop yields.
What Are the Vegetable Families?
When you do crop rotation, the first thing to do is learn to identify your vegetable “families”, that is, what plants have somewhat the same growing habits and features. Creating a rotation plan on paper each year makes crop rotation easier to track.
There are seven main vegetable families:
1. The Mustard Family which includes broccoli, radishes, brussels sprouts, cabbage, turnips, and kale. These are Heavy Feeders and grow best in soil with lots of organic matter. If possible, plant where members of the pea family had been planted.
2. The Gourd Family, which includes melons, cucumbers, pumpkins and squash, are also Heavy Feeders and require plenty of organic matter for proper growth. You might precede these with grass family and follow with pea family.
3. The Pea Family, which includes beans, peas, clovers, and vetch, actually add nitrogen to the soil, especially if turned under into the soil at the end of the growing season. These plants gather nitrogen from the air and “fix” it on root nodules. The Pea family can be rotated with any other plant family .
4. The Grass Family, which includes corn, wheats, oats, rye and alfalfa, improves soil especially if turned under at the end of the growing season. Plant before gourds or nightshades.
5. The Lily Family, which includes onions, garlic, leeks, and chives, cannot be planted in soil that has large quantities of organic matter (such as green manure) that have not yet decomposed. These can be rotated with the pea family.
6. The Nightshade Family, which includes tomatoes, potatoes, eggplants, and peppers, are heavy feeders. They need soil with lots of organic matter. The nightshade family should be preceded with the Grass family followed with pea family.
7. The Carrot Family, which includes parsley, celery, carrots, dill, and coriander, are moderate feeders. Precede with any other plant family and follow with pea family plants.
Now that you know what plants make up each family, the second step when setting up crop rotation is to take a clean sheet of paper and draw your basic garden design. In order to make your plan and your crop rotation much easier, grow all the crops in the same family next to each other so they form large blocks. (You might consider companion planting as well. See post on companion planting to see which plants would work well together and which ones don’t.)
Here is an idea of how you can set up your garden groups. (Note: Again, onions and garlic from the lily family are great companion plants, so you could plant those on the edge all around the entire garden. Many gardeners include flowers in their vegetable gardens for pest control effects. Make sure whatever crops you pair are compatible.)
Click on the chart to get a better view of how the crops are set up in families. Then if the chart is not big enough, click on the little page magnifier.
The idea is to rotate your groups from area to area each year. You might even consider choosing one of those areas each year just for growing alfalfa or another grass family crop and turning it under back into the soil to enrich the soil with nutrients. (This is known as green manure.)
If you chose a different section of your garden every year, the soil in each section would have had the time to rest from heavy feeders and replenish itself)
( Thoughts for you: In the fall, I would make my green manure by first gathering leaves, breaking them up with my lawn mower and burying them in the garden. Then I would plant alfalfa before the weather got too cold, let it grow some in the spring, and turn it under before it came to seed to give it time to decompose before I planted my crop. The idea here is to get the worms interested in staying in your garden. The more worms in your garden the better it is for the crops. Worm droppings are among the top best fertilizers.)
Alternating plants that add nutrients to the soil with those that deplete soil helps to keep your garden fertile and will also reduce the need for chemical fertilizers. Crop rotation produces healthier plants and greater yields. You might want to give it a try!