Easy Crop Rotation Using the Colors of the Rainbow

, written by gb flag

Crop rotation by family using color groupings

After designing the overall layout of your garden, the most important element of garden planning (and the part that recurs year after year, which is why you should spend time every winter thinking about it) is crop rotation – planting crops in different positions each year. It may seem complicated, but there are really just two main approaches to crop rotation – rotating by edible parts, and rotating by crop family.

The Problem With Rotating By General Plant Type

Traditionally, three or four equal sized beds are planted up with crops which are divided into fairly generalized categories, such as fruits, shoots and leaves, with perhaps an extra category for ‘pods' – peas and beans. However, while this system is simple (you can tell where to group a plant based on the part you're going to eat) it does have a major drawback – plants which belong to the same family, and therefore suffer from the same soil-borne pests and diseases and draw the same nutrients from the soil, don't always produce the same type of edible part.

Consider tomatoes and potatoes, for instance. Both are members of the Solanaceae family and both are extremely susceptible to the same type of blight that can wipe out whole crops, but under this system they would be classed as fruits and roots respectively, and so could follow one another and pass on the disease to the next crop.

Using a three-bed rotation, peas and beans commonly occupy a fourth bed and are grown in the same spot each year to avoid having to move cumbersome supports, but while legumes are typically fairly trouble-free there is still an increased risk of a build up of pests and diseases in the soil. Peas and beans are a very useful part of a successful rotation cycle due to their nitrogen-fixing qualities, the benefits of which are passed on to the crops that follow them in rotation.

Rotating Crops by Crop Family

A better way to rotate annual vegetables is to group them by their plant family. This means you can group plants with similar maintenance requirements together – for instance, all plants in the cabbage family are best grown together to make it easier to net them against cabbage white butterfly and birds – and there's no risk of accidentally passing on crop-specific soil-dwelling pests and diseases to the next crop.

If you want to get really geeky about crop rotation – and I do – you can also plan a set rotation order, and a really handy way to do that is to give each plant family a shade relating to the colors of the rainbow, as shown below.

  Year Color Family
1 Lilac Alliaceae (onion family) – onion, shallot, leek, garlic
1 Blue Leguminosae (pea & bean family) – all types of pea and bean
2 Green Brassicaceae (cabbage family) - calabrese, Brussels sprout, broccoli, cabbage, kohl rabi, cauliflower, kale, mizuna, pak choi, radish, arugula, rutabaga, turnip
3 Yellow Solanaceae (nightshade family) – potato, tomato, peppers, eggplant
4 Orange Umbelliferae (carrot family) – celery, celeriac, cilantro, fennel, carrot, parsnip, parsley, dill
5 Salmon Cucurbitaceae (marrow family) – zucchini, cucumber, marrow, melon, pumpkin, squash
5 Pink Chenopodiaceae (beetroot family) – Swiss chard, perpetual spinach, true spinach, beets
Any Grey Miscellaneous (non-rotation annual crops) eg basil, lettuce, endive, cress, sweet corn, okra, salsify, scorzonera, New Zealand spinach, corn salad, chicory

Working from the inside of the rainbow out, you can see which plants belong together and which should come next in each bed. The rotation starts with lilacs and blues – onion family plants and peas/beans – which are commonly grown together as they both like soil enriched with compost and take up little space. Once you've harvested your onions and beans from your first bed, the next crop in that spot would be cabbages, cauliflowers and broccoli and so on, for the first seven categories.

Using this order of rotation is optional but it helps to make sure that the soil is in the correct condition for the following crop.

Plants in the Miscellaneous (grey) category are useful for plugging gaps in your beds as they don't tend to suffer badly from particular soil-borne pests and diseases, and can be fitted in anywhere you have room, although it's still a good idea to move them around from year to year as much as possible, particularly sweet corn which can suffer from rootworms.

Our Garden Planner makes things even easier, as each plant icon is color-coded so you can quickly see at a glance which family it belongs to.

Original article published February 20 2014.

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Show Comments


"Hi. I am very intrigued my your planting by color strategy. However, in the program I am seeing that potatoes, tomatoes, peppers and eggplant are all the same color. While they are all in the same family, every resource on companion planting I have found says to not group them together. Tomatoes can lead to potato blight for potatoes. And planting all of these together can cause a build up of blight in the soil, even if you rotate out of that box. Can you speak to this? I am pretty new at companion gardening and am concerned at the contradictory recommendations."
Jennie on Thursday 3 April 2014
"Hi Jennie. Blight spores are spread by the wind, so if it occurs in your garden it's highly likely that both potatoes and tomatoes will suffer even if they're kept in different beds. If you type 'blight' into the search box on the right hand side of this page, you'll find a number of excellent articles about dealing with the disease. You don't necessarily need to group plants from the same family together - the important thing is to avoid replanting a particular family in the same spot year after year to help prevent a build up of pests and diseases. "
Ann Marie Hendry on Thursday 3 April 2014
"I only plant from 2 of the families. I usually rotate each type of plant, but since they are all in the same family ( 3 and 5) I am considering having an empty bed each year. What are your suggestions for this?"
Ann on Tuesday 8 April 2014
"Hi Ann. That sounds like a great idea. However, I wouldn't advise leaving a bed completely empty - instead, grow a green manure/cover crop from a different crop family which will protect and enrich the soil, suppress weeds and attract beneficial insects. There are lots to choose from - take a look at Jeremy Dore's article here: http://www.growveg.com/growblogpost.aspx?id=49, or Barbara Pleasant's article on growing buckwheat here: http://www.growveg.com/growblogpost.aspx?id=184"
Ann Marie Hendry on Wednesday 9 April 2014
"I only grow winter brassicas such as Russian Kale, Purple sprouting and calvo nero. What would you suggest following them with?"
jacqui Howlett on Saturday 18 April 2015
"Hi Jacqui, why not try something from the Solanaceae family (shown in yellow above) which includes potatoes, tomatoes and peppers. Good luck with trying something new!"
Ann Marie Hendry on Saturday 18 April 2015
"One problem I've had with trying to plan crop rotations, is everything I read seems to indicate everything changes together. I live in a sub-tropical climate, and never get frosts or freezes, a lot of things can be grown all year, which is great, but complicates crop rotation planning a bit. For example, in my climate, I often keep my chilli plants (peppers) going for 2-4 years (and they often do better after the first year, the plants get bigger and produce more), where other things only last a season. I've heard it's mostly important to rotate Solanaceae, Brassicaceae, and Alliaceae, and the others aren't as important in regard to disease build-up. Would you agree? I thought if I grew solanaceae in one bed for 3 years straight, but then make sure there's 4 years before they go in that bed again, and then plan rotations to also make sure there's a 4 year gap between brassicaceae crops in a single bed, and then just fill in with other things. (I don't really grow anything much from alliaceae family.) But trying to plan full rotations where there's a gap between all families, when solanaceae last several years... I haven't been able to work out any way to do that."
Chris on Wednesday 23 September 2015
"Hi Chris. It's probably unnecessary to rotate your chillies each year if you're growing them as a short-lived perennial - just rotate to a new bed when you plant new chillies. Solanaceae, brassicas and alliums are the most troublesome crops when it comes to soil-borne pests and diseases, so I would agree that these are the most important crops to rotate, even if you can only manage a gap of a single year between crops of the same family. I wouldn't recommend growing them in the same bed for several years in a row as problems can build up in the soil that way, plus it can result in the soil becoming exhausted of key nutrients for those crops. Crops from different families can be grown in the same bed and rotated as one. "
Ann Marie Hendry on Saturday 26 September 2015
" One comment/question: On just about every other rotation and companion planting site I've seen, it is stressed NOT to combine or have as near neighbours legumes and aliums as they stunt the growth of the other. ( You state above: "The rotation starts with lilacs and blues – onion family plants and peas/beans – which are commonly grown together ") Thanks for your comment on this part."
EEK on Tuesday 18 October 2016
"I hadn't heard that legumes and alliums were not supposed to be grown together. I (and many other gardeners) have been growing them side by side for years with excellent results. As with most companion planting advice, take it with a pinch of salt. In my opinion, the most important consideration when growing two crops from different plant families together is making sure they will both enjoy the same soil conditions. As long as the soil is right, they should perform well together. But having said that, every garden is different, so it's fun and worthwhile to experiment with companion planting 'rules' to see if they work for you or if they're just an old wives' tale!"
Ann Marie Hendry on Tuesday 18 October 2016
"The photo above ... Do you have a plan with dimension? Love the layout and have the room"
Kristi on Sunday 12 February 2017
"Hi Kristi, it is a beautiful vegetable garden in the photo at the top of the page but unfortunately it's not mine so I don't have the plans. "
Ann Marie Hendry on Tuesday 14 February 2017
"Hi Ann, thanks so much for this incredible valuable article and for taking the time to categorising all the plants in the gardenplanner database. This part is going to be the most valuable resource for me in the coming years, looking after 7 garden beds applying these principles. I noticed that there is a large “grey” category and I’m curious to see if in the future some of these plants will move into some of the other coloured categories as perhaps more scientific evidence emerges. For a future article, what would be really great to have is a downloadable rainbow PDF chart with a list of names and images of all the plants. I might even create one for myself. After reading the article, I have one question about succession planting. Based on these principles, would it be allowed to replant plants from the same colour within the same year? I’m planning to rotate my beds only once a year. Many thanks again! "
Ivo on Wednesday 27 December 2017
"Hi Ivo. Excellent question! Many gardeners (myself included) continue to replant in the same place during the same year with plants from the same colour (which represents the crop family the plants belong to). If you do this however it's important to make sure to replenish the soil, for instance by adding a mulch of compost, as the soil will tend to become depleted of the particular nutrients that that crop family relies on. If replanting with a different crop family, this is less of an issue, although it's still best to add some compost or other slow-release fertiliser if you can. Some gardeners religiously rotate crops from different families within a single year, however this can get very complicated, and in my opinion is not important in most cases (those with a very long growing season may disagree!). Having said that, one reason why you might wish to change to a different crop family is if your plants have suffered from a crop-specific pest or disease that could be transmitted through the soil to the next crop. The plants grouped as 'Miscellaneous', in the grey category, don't belong to one of the main crop families and tend not to suffer badly from soil-borne pests or diseases, so it's unlikely they'll be grouped with one of the colour-coded crop families in the future. The Garden Planner uses this colour coding as a coloured background on each plant on your plan to make it easy to group plants from the same family together (plus it also warns of crop rotation conflicts in future years when you create follow-on plans). Happy New Year, and good luck with your garden in 2018!"
Ann Marie Hendry on Wednesday 27 December 2017
"if I only have 4 beds would it be possible to combine some of the other groups together? for example i wash thinking of combining Umbelliferae and Chenopodiaceae."
Tony on Thursday 15 March 2018
"Hi Tony. Most gardeners find they need to grow some of the plant families together in the same bed, unless they have unlimited space! Umbelliferae and Chenopodiaceae should be fine together. The most important thing is to avoid growing plants from the same family in the same spot every year."
Ann Marie Hendry on Friday 16 March 2018
"Hi there :) Thank you for a great article. My problem is this: I simply don't grow potatoes! I have limited space which I can divide into three beds rotated each year. (I do have a small permanent bed in which I grow some cane fruits). Traditionally, I've grown alliums and Roots in the same. bed at the same time, Brassicas share a bed with sweetcorn, Chard, spinach and salad and I have grouped solanaceae and Cucerbites together in the same bed with additional of these last groups grown in pots or bags elsewhere in the garden. Am I asking for trouble in the longer term? Thank. you for. your advice, Kindest regards, Karl."
Karl on Saturday 13 April 2024
"Hi Karl. If this has been working well for you so far I see no reason not to continue. Ideally, beds would only see plants from a specific crops family no more often than once every five years - or even longer - but when this isn't possible it's really just a case of rotating as much as you can. Mulching with organic matter like compost every year will help massively with soil health too. "
Ann Marie Hendry on Saturday 13 April 2024

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