Rotation


Crop rotation is one of the most important things you can do to ensure a successful garden from year to year.  In The New Organic Grower, Eliot Coleman calls it a “conservative estimate” to say a good rotation is worth three-quarters of everything else you could possibly do to improve your crop potential.

The basic idea behind crop rotation is to move crops and crop families into different parts of the garden from season to season (or even within the same season, if you succession plant–putting more than one crop in the same space in the course of a single season).

A more sophisticated rotation plan takes into account which crops do better after which other crops and tries to organize the rotation to take advantage of those small improvements (called “one percenters” in the biz).

There are a few ways in which a crop rotation can really help, even if it’s not terribly sophisticated–moving crops can lessen the chance of disease problems in a certain crop or crop family; it can help confuse insect predators by not having their favorite crop to munch on when they wake up (It was there when I went to sleep last winter, I swear!).

Plants from different families also have different nutritional needs, so moving crops can avoid nutritional deficiencies that might result from the same kind of feeding by the same kind of plants in the same spot over and over.

My own crop rotation is not as sophisticated as I’d like it to be–mostly because a few parts of the garden have gotten a bit out of control in the last couple of seasons.  Some of the decision about what to plant where is dictated by where I can plant when, depending on the amount of spring clean-up an area of the garden needs.

However, I do make a concerted effort to practice the best rotation I can under my own circumstances.  A strict rotation matters less with some crops than others–sugar snap peas and tomatoes often get grown on the same trellis for more than one season simply because it’s so much work to pull, move, and re-erect the things every spring when it’s pea-planting time.

Too, a lack of space that can reasonably accommodate trellis coupled with the number of crops and row-feet of those crops I need to plant can clash with rotational principles–there’s only so many locations in the garden that work for cattle panels, and there are a lot of sugar snap peas, pole beans, tomatoes, and cucumbers that need to grow up.

Still, I try to move those trellises every two years in order to get those crops in a new soil, which also lets the crops that follow the beans and peas take advantage of the nitrogen their leguminous roots fixed.

Two crops that I follow a very strict rotation with, and try to get a reasonable distance apart (at least two rows) every season (and even within a season) are cucurbits (squashes, cukes, and melons) and brassicas, also known as cole (or kohl) crops.

Both of these crop families like fairly rich soil, and both are plagued by two different pest issues: cucumber and squash beetles for the cucurbits, flea beetles and cabbage moths for the brassicas.  These are pretty much the only major pests in my garden, and every year I try to outsmart them with (sometimes limited) success.

Brassicas are really the biggest headache, and their rotation takes up a lot of my brain-space when I’m doing spring planting.  I keep good records and maps of what I’ve planted when, but the sheer number of brassicas I grow (or try to) every year makes rotating them–and keeping that two-row distance–a major challenge.

Last year’s brassica line-up included kohlrabi, broccoli, cauliflower, cabbage, kale (two kinds), and broccoli raab.  Too, there are certain crops that, while they are not technically brassicas, have some of the same pest issues: arugula, radishes (spring and fall), and turnips.  Potatoes and eggplant, too, suffer from flea beetle attacks, so I have to keep that in mind when planting the following season.

While floating row cover is my strongest ally in protecting these crops from flea beetles, the fertility/potential for disease issues are not to be worked around–brassicas just get extra love in my garden–meaning lots of composted manure and rotation every season.

This year, my brassica line-up inclues broccoli, cabbage (one spring and one fall), broccoli raab, kale (probably two, maybe three kinds), kohlrabi, Chinese cabbage, bok choi, and Brussels sprouts.

While working up a couple of rows in the north central garden today, I’d planned a 2′ x 30′ row of Goddess salad mix, and the same size row of what I thought would be parsnips. But then the brassica equation came into play.

The Goddess mix went where eggplant was last year (manure applied and worked in) because that area might be a flea beetle issue, and flea beetles don’t generally bother lettuce.

I kept arugula separate from the mix (under row cover in a different part of the garden) in order to avoid it being shot full of little holes by those nasty little hopping critters–but don’t worry–the Goddess mix will contain that spicy extra kick. I’ll just blend it separately.

But that second row I worked up (and where I was planning on planting parsnips), suddenly seemed like a very good place to get a brassica or brassica-like crop in.  It’s a relatively weed-free space (good for direct seeding), so instead of parnsips or even carrots, the idea of putting in some broccoli raab in there got very attractive indeed.

I haven’t done it quite yet–it was getting late and a vision of crisp white Hakurei turnips was competing with the raab. I’ll make the decision tonight and get the planting done tomorrow.  It seems like I have a good amount of greens already in (all that spinach, plus arugula, lettuce, and the salad mix), so a root crop is tempting.

Still, I’m now focused pretty seriously on planning out space for all those brasscias–the spring cabbage, broccoli, and Brussels sprouts can go in a slightly weedier spot since they are transplants, so easier to hoe around.

Kohlrabi and kales (plus red cabbage and Chinese cabbage) will be planted in late summer for a fall crop, so they can wait their turn.  But bok choi and broccoli raab need a suitable rotated and manured weed-free seed bed very soon!

This is all to say that while crop rotation may seem more of a pain than it’s worth–trust me, it’s very much worth your trouble, and unless you are a highly diversified vegetable crop grower like I am, chances are it will be much less logistically complex than what I’m dealing with!

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