Blogger’s note:
In 2010, I took my first stab at blogging about gardening. One of the first topics I covered was crop rotation, to me, one of the essential concepts to master in order to become a successful vegetable gardener. My knowledge of crop rotation came from an article in a short-lived magazine called “Kitchen Garden” in 1997. When I wrote my article about crop rotation in 2010 I was going totally from memory because, like a fool, I had misplaced/lost that issue. That post has since been viewed over 12,000 times. However, I was unable to credit the original author because I had forgotten her name. I have since acquired a copy of the original article.
This post has two goals. First and foremost is to acknowledge the author who’s article changed me from a mediocre gardener to a consistently successful one. Next, I will restate the principles of crop rotation that I practice with the goal of bringing greater clarity to this subject.
Crop Rotation – The Four Crop Rotation Revisited
Have you ever read something that literally changed your life? In early 1997, I had that very experience in the form of an article in “Kitchen Garden” magazine entitled “Yes, You Can Practice Crop Rotation”. Written by farmer and farmer’s market director, Cynthia Hizer, it described a simple four crop rotation that was easy to follow and which I have used successfully for the last nineteen years.
In the ten years before reading this article I had made several attempts at vegetable gardening, relying on a little reading and a lot of trial and error. Until then, I had never encountered any information regarding crop rotation that made much of an impression on me. When I read this article it was like getting hit on the head with a brick and all of a sudden being able to sing like Tony Bennett. OK. Maybe not that cool. However, this knowledge allowed me to become a very good vegetable gardener, the kind of gardener that other gardeners turn to for advice.
Why is Crop Rotation so Important?
Planting the same crop in the same place year after year leads to some bad voodoo. First of all, the soil will eventually lose the nutrients necessary for proper growth and health. If you continue to plant crops in the very same place year after year, insects will figure this out and move in permanently. Believe me, this is not good. The same goes for diseases, especially fungal diseases. I have read that fruiting vine crops like squash, cucumbers and melons need to be rotated on a four to five year basis in order to avoid various soil born diseases. So, plant nutrition, disease resistance and insect infestation all seem to be good reasons to rotate your crops.
Four Crop Rotation – An Elegantly Simple Solution
The key to this four crop system is organizing crops based on their nutritional needs. The four groups break down to leafy crops, fruiting crops, root crops and legumes. Leafy crops like lettuce and cabbage need nitrogen. Fruit crops, on the other hand like phosphorous. Root crops require potassium. The fourth group is legumes. It’s not so much what they need. It’s more about what they produce – nitrogen. Hmm! And leafy crops like nitrogen? It sounds like the beginning of a plan.
So where does the phosphorous and potassium come from? Soil amendments, most commonly rock phosphate and green sand. At the heart of this crop rotation system is a program of adding soil amendments at just the right time and that time is at the end of the growing season and the place where these amendments are added is the legume bed.
What makes this work so well is that the rock phosphate and the green sand need time to break down so that plants can make use of the available elements. If you plant leafy crops in last season’s legume bed, they will benefit from the available nitrogen produced by the legumes. In season 3, the phosphorous released by the rock phosphate will be available for the fruiting crops like tomatoes, peppers, eggplants, cucumbers, melons, etc.By the time the root crops make it to this bed in season 4, the green sand has released it’s potassium to the soil. Cynthia; you are a genius.
FOUR CROP ROTATION
SEASON 1 SEASON 2 SEASON 3 SEASON
LEGUMES LEAF CROPS FRUIT CROPS ROOT
PEAS LETTUCE TOMATOES ONIONS
BEANS SPINACH PEPPERS BEETS
FAVA BEANS KALE EGGPLANT CARROTS
CORN VINE CROPS
END OF SEASON
ADD Plant garlic
Green Sand
Rock Phosphate
Lime
Plant hairy vetch
I have to admit that “legumes” were not part of my gardening vocabulary when I first started gardening. That changed after reading Cynthia’s article and our lives are richer for it. We discovered “Haricot Vert”, the delicious french filet beans. They are the best. We also discovered fresh peas; one of the very best reasons to grow your own vegetables. If you don’t garden, then you don’t know one of the great pleasures in life – fresh peas. We also grow beans for drying; enjoying them in soups, stews and chili during the Winter months.
Putting These Principles into Practice
The obvious first step in implementing the “Four Crop Method” of crop rotation is to divide your garden into fourths. I have sixteen planting beds in the main garden; four for each plant group. I draw up a new garden plan each year, planning my rotation so that leaf crops will be planted in last season’s legume beds. The fruit crops will go into the beds where last season’s leaf crops grew. The root crops are planted in last year’s fruit crop beds. Legumes are planted in last season’s root crop beds, starting the whole cycle over again. Here’s how I organize each group:
LEAF CROPS
Lettuce
Spinach
Kale
Cabbage
Cauliflower
Baby Lettuce Greens
Broccoli
Brussels Sprouts
Corn
FRUIT CROPS
Tomatoes
Sweet Peppers
Hot Peppers (Grown at least 25 feet away from sweet peppers)
Eggplant
Cucumbers
Melon
Squash
Zucchini
ROOT CROPS
Onions
Shallots
Green Onions
Leeks
Carrots
Beets
Swiss Chard (Related to Beets)
Turnips
Radishes
Bulb Fennel
LEGUMES
Peas
Green Beans
Fava Beans
Snow Peas
Beans for Drying
Hairy Vetch (a weed that is also a legume, planted after soil amendments have been applied. Plowed under in the Spring, adding more nitrogen and green matter to the soil)
Some Exceptions to the Rule.
You may have noticed that potatoes are not listed in the rotation. Spuds present a dilemma; they are related to tomatoes (nightshade family), and they like a more acidic soil than most vegetables. I get around this by planting them in a separate garden in a three crop rotation with legumes and Winter Rye. We already know about the nitrogen producing properties of legumes. The Winter Rye helps loosen the soil and repels nematodes who would prey on the potato tubers. If you don’t have room for a separate garden, I would suggest that you grow potatoes in a container and change the soil every years.
Another exception, actually, more of a timing issue is garlic. Garlic is a root crop which is planted in the fall; late October in my neighborhood (zone 6a). What I do is clean up a fruit crop bed, apply some compost and plant my garlic there. It is going to be a root crop bed next season anyway, so that’s where it’s going.
Oh Yes, Almost Forgot
At the end of the season, I add compost to next year’s fruit crop bed, root crop bed and legume bed. Building soil with organic matter is what we do. Over time, this creates a nice loose soil that retains enough moisture but also drains well.
Summary
Thoughtful crop rotation is a key component of a successful vegetable garden.
Divide your garden into fourths, group like vegetables together into the following: legumes, leafy crops, fruiting crops and root crops.
At the end of each season add the following amendments to the soil in the beds where you grew legumes: rock phosphate, green sand, lime (if your soil is naturally acidic like mine), and compost. It is also a good idea to plant hairy vetch in this bed as well after you have applied and tilled in the amendments.
I welcome your questions and comments. If you are still a bit confused, by all means send me a comment. The goal is to help you be a better gardener. That’s my mission.
All the best,
Greg
