Make sure you rotate your crops each year

By Melanie Mathieson
Gardening Guru

As we are ready to plant the first seeds in our vegetable gardens, it will pay to do a little advance planning before you rush out and throw those seeds in the ground. I am talking about crop rotation which has been used for centuries. For good soil nutrient management our ancestors, commercial agricultural growers and home gardeners all practice crop rotation each year.
A good gardener will use crop rotation for two reasons. The first reason you should rotate and change the location of your annual vegetable crops from year to year, is to ensure good soil nutrient supply. All plants require good soil nutrients to grow so we add fertilizer to our gardens to help in this process, but different plants draw different nutrients from the soil in different quantities and at different rates throughout the growing season. By changing the location of the plant in the next year you can place a different type of vegetable in the same place and it will draw different nutrients from the soil. This helps to prevent the crops from robbing all of the nutrients from the soil in a matter of a few short years. Crops such as peas and beans (legumes) put nutrients back in the soil as they grow. This family of plants is known as nitrogen fixing. The roots of legume species have little nodes that take in nitrogen and then ‘fix’ it in the soil. Because of these benefits you will want to keep rotating your beans and peas all around your garden so you can build the nitrogen stores in the soil. It is also good to know where you planted theses crops last year so if you want to plant a crop that requires lots of nitrogen (corn) you can plant it in one of the areas where the legumes where last year. The other reason for rotating crops is for pest control. Although some plant species share the same pest problems many plants have garden insect pests unique to them or the family of plants that they belong to. Some pests and diseases can lay dormant in the soil over the winter months, just waiting for you to pop that vegetable back in the ground in the spring. By changing the location of the vegetable you help to reduce the infestation of pests and diseases specific to that plant.
Crop rotation can be used in your vegetable garden regardless of the size of the garden. You may not be able to achieve a full rotation in a small vegetable garden but with careful planning you will be able to rotate most crops. A larger garden is easier to rotate the crops from year to year because you have more space and more options for planning out the crop placement when you have more room. It is highly recommended that you make a map of the crop layout of your garden each season. This will help you to remember where plants were placed last year and how you will rotate the crops for this season. I am sure the majority of vegetable gardeners didn’t do this last season so you will have to rely on your memory for this year and make this a “new garden resolution’ for this year. Making a map of your crop placement is very easy. All you need is some blank paper or graph paper and a pencil. You may want to measure out the dimensions of your garden so you can record the placement of everything more accurately. With the exception of potatoes and corn, I always plant my crops in wide beds (rows). These are very easy to draw on the diagram. When i lived in Fort Frances, my garden was almost 50 feet by 50 feet, so I had a lot of room for rotation. I usually planted one-third to one-half in potatoes so I flipped one half to the other side in the first two years and then rotated the half of potatoes ninety degrees to the bottom or top and then flipped to the opposite side the next year. This planning gave me four years of potato crop rotation. Because I have flipped the largest crop first the other crops were automatically rotated when I place them in the remaining part of the garden. This is fairly simple but with one exception. You shouldn’t plant the same crop in the same place each year but also another plant from the same family shouldn’t be planted in the same spot. This means that although I have rotated the potatoes and can plant in the remaining space I shouldn’t plant tomatoes, peppers and eggplant in the same spot as the potatoes were last year. Because the garden crop of potatoes isn’t exactly half I find that I can always find a good spot between the rotation areas for these species of plants. Another thing to keep in mind is that if you are planting corn it always grows best where you had legume species the year before, also corn will grow very tall and can create a ‘fence’ that can block the sun from the rest of the garden.
For any size garden a great way to practice crop rotation is to divide the garden into four quarters. Each quadrant can grow specific vegetable and then just rotate the crops in the quadrant, clock-wise each year. You can also change the location of the crops within each quadrant if you like too. By using the rotation of a quadrant you will grow the same crops in the same part of the garden once every four years. This is a fantastic way of rotating your crops. Now of course this sounds great in theory and should work for the most part, but in reality you just may run into a situation where you shouldn’t plant the same family year to year in the same spot or two plants can’t be side by side in the garden, etc. Just do the best you can and keep good records so you can make adjustments the following year. Your map is a good place to mark the variety name of your crop so next year you will know whether you want to grow that variety again. It is always good to keep notes on your map about how each crop did in its location. Notes like too much sun and too much shade will help you to streamline crop placement in future seasons.
The purpose for this column is not for you to perfectly place your crops in the garden year after year but to get you thinking about good soil nutrient management. You may have been planting the same plant in the same spot year after year and have been complaining that this plant doesn’t seem to grow like it used to. So do your best to rotate the crops based on what your garden has to offer for space and sun exposure and give some thought into the future as you place the crops for this season. Crop rotation is just another tool you can use to help you become the best gardener you can be and to produce the best vegetables.