Rotating different crops to assist with soil fertility is as old as agriculture. Many gardeners I know avoid crop rotation because it can be tricky to apply and yet its another free organic gardening method to improve the productivity of your food garden, just like using the planets. My blog this week talks about how to work with and get the most benefit from crop rotation in your organic vegetable garden.

All successful organic and biodynamic farmers and gardeners are very conscious of the delicate balancing act they participate in by working their soil to grow food, whilst at the same time, aiming to progressively increase soil fertility. If the soil is pushed too hard, the plants will lack vitality and attract pests and diseases. If the soil is cared for as the top priority, then your green thumb will appear, resulting in a very productive food garden.

Crop rotation should be considered as part of your soil fertility tool kit. In simple terms, crop rotation means that in the different beds of your food garden or farm, you do not grow the same vegetables or grains over and over in the same location. You move crops around in a pattern with the sequencing of this pattern eventually resulting in the same crop returning to the original bed. How you work with this pattern is the art of crop rotation.

There are a number of different methods of crop rotation used in organic gardening. I will talk about the method I use which is based on biodynamic gardening principles and can be applied to any food garden or farm. Our Gardener subscriber web site has lots of searches to support the method I will describe.

The starting point is to allocate your vegetable, herb and grain crops into the following groups:

• Root: for example, beetrrot, carrot, turnip and potatoe

• Leaf: for example, lettuce, cabbage and asian greens

• Flower/seed: for example, caulflower, wheat and broccoli

• Fruit: for example, beans, cucumbers and tomato

These grouping are based on the predominant part of the plant you eat. You can search all the vegetable, herbs and grains in our site by these groupings in the Gardener subscriber site.

A rotation should follow the pattern of : root, leaf, flower/seed and fruit. This follows the way plants grow and will bring a natural balance into the soil. It is helpful to insert a green manure crop into the pattern and the ideal time is between root and leaf crops. You can see a lengthy article and movie of mine on using green manure crops here.

To apply this rotation pattern in your garden, its best to have your garden beds in fives because there are five groups: root, green manure, leaf, flower/seed and fruit. In one of our vegetable gardens we have 15 beds and in another we have 5 beds, always multiples of five. Its ideal to start the groupings all at once. By this I mean, do not start all root crops at once in the whole garden because this will limit your diversity. Only have root crops in one bed and in the other bed have fruit crops and so on as you fill your beds in multiples of five. Even if you have a small garden you still split the space into five.

To help with planning this, get a sheet of paper and place columns across representing your main growing seasons, for example in my climate I have Autumn and Spring, so there are two main seasons per year and I will list this across for three years, ie six cycles. Then down the rows have your beds listed. In one row for a bed follow the sequence of root, green manure, leaf, flower/seed and fruit. Then for the next bed row start with green manure so its out of sequence to the first bed row, then with the next bed start at leaf and so on. Now you have a high level rotation plan and you are ready to decide on the crops to plant at those times of the year. Our Gardener subscriber planting calendar provides you with the information you need for this task.

As you decide on the crops for your beds, its important to recognise the concept of the predominant crop. By this I mean that if you have broccoli as your predominant crop in the bed taking up most of the space, then its ideal to have companion plants with it to help these crops and even understory plants to take up the space. When I plant broccoli, I use nasturtium, marigolds and corainder as companions to help with pest reduction and in the space between the high growing broccoli's I will grow lettuce as an edible ground cover crop. Use the companion search in our site to help with these choices for all crops.

If you have a new garden with brought in soil or a dug up lawn, then I suggest starting with a green manure crop over your whole garden and then commencing the rotation pattern. This will ensure your garden space receives a good tune-up before you start growing food.

Some other important factors to consider:

1. Recording - Make sure you have these two written planning tools:

2. Crop families – All food crops below to botannical families. You can find these families in the plant search in our web site. Its important to not follow one family with the next family in the same bed, as this can keep soil borne diseases around longer. This principle can sometimes become tricky when following the rotation pattern recommended above, for example, the brassica family includes cabbage which is a leaf crop and broccoli which is a flower crop, so if your rotation had predominant crops of leaf group (cabbage) followed by flower group (broccoli), you would be keeping the same family in the bed. In my experience, the way around this is to not make the second group a predominant crop

There are further instructional resources in our Gardener subscriber site on crop rotation and many search tools which help with plant selection and timing, including rotation considerations on every crop based on families. 

Later this year, we plan to release a major new feature on our web site called the Garden bed manager which will allow you to keep a full history of your garden beds and greatly assist with rotation planning, plus lots of other features to help manage your food garden. Much work to do before that new feature is released!

Happy rotating.

Author: Peter Kearney – www.cityfoodgrowers.com.au