Monday, January 30, 2017

crop rotation

I recently finished making plans for my vegetable gardens and posted the diagrams. A reader noticed I always plant my butternut squash in one place: on the arbor in the middle of my community garden plot. I like it there. It looks nice and does well.

But the reader asked: Why don't you rotate its location?

Well my view is crop rotation is more often important for farmers growing big fields of vegetables. Growing in a small space is different. It's hard to separate plants in a 500 sq ft space. I've heard and read this, most recently from Victory Garden TV host Roger Swain at a class he gave for my Master Gardener training.

Crop rotation can be done to reduce pathogens or build soil. When thinking about pathogens, many are windbourne or spread by insects, splashing, tools, or the gardener. For these, moving crops a few feet to another bed doesn't help much. There are also crops that don't have many pests in a given area and there's no need to rotate these.

Crop rotation to build soil is a great idea even in a small garden. Squash is a heavy feeder, so I could plant a crop that doesn't like a rich soil, like carrots, in it's place the second year, and then a legume like pole beans to build up the soil the third year, and then in the fourth year go back to squash. Maybe some year I'll try this. Drawbacks are the time it takes to plan out the cycles. Also, here is a tendency for home gardeners to grow many more heavy feeding plants than light feeders or soil builders. And, it's not so hard to get a few shovelfuls of compost and enrich a small patch of soil annually. Anyway I don't rotate for soil building.

I do make sure to rotate crops that are susceptible to soil pathogens in my gardens. These include: 1. Root vegetables, 2. Tomatoes, and 3. Brassicas.

My root vegetables include carrots, parsnips, potatoes, sweet potatoes, onions, garlic, and scallions. (I haven't seen any problems without rotating celeriac and beets.) All alliums (onions, garlic, leek, scallions) need to be considered the same and none should go in the same bed without a break. I rotate them on a three year schedule. The same for tomatoes and brassicas. (My brassicas include broccoli, bok choi, cabbage, and kale.) To make it easier to rotate these, I plant each in their own bed.

Plants I don't rotate are my greens, legumes, herbs, flowers, and squashes. These don't benefit enough from rotating in my small garden. For example, my squash is prone to stem borer, downy mildew, and cucumber beetles. Moving its location won't reduce these. So I add a good pile of compost along my arbor and keep planting the butternuts there.

I'd love to hear how other gardeners handle crop rotation. I'm sure there are lot's of approaches.

8 comments:

Anonymous said...

In my small garden I don't have the luxury of radical rotation, I just am very careful not to plant the same veggie in the same place each year. I pay more attention to companion planting, plants that benefit each other and those that don't. For example tomatoes love parsley but peas do not do well near onions (allium family). I also try not to plant where their foe grew last year...for example peas where onions grew. There are good companion planting lists available on line...nw organic gardener

Anonymous said...

I keep similar plants together and rotate everything on a three year schedule, except potatoes. I grow potatoes in 30 liter pots, in the same location, and use fresh compost in the pots each year. Once a pot is emptied of potatoes, I usually plant another crop, such as peas, in the pot. At the end of the growing season, the spent potato pot compost gets distributed in the flower beds. I have tried to grow green manure to enrich the soil but have found that this complicates the rotation considerably because these plants are also legumes, brassicas, etc. it seems to be far easier, as you say, to just throw in some compost and composted manure with some organic fertilizer each year. I don't know if you've looked at Charles Dowding's no dig gardening method - he has been experimenting with growing the same type of plant in the same location year after year and comparing yields. DebS.

JustGail said...

While the garden is good-sized and would allow for about a 5 year rotation, it's too close to a black walnut at one end. So I keep waffling, move the garden? Remove the walnut (we have others and the squirrels are the only ones eating the nuts)? Let that end of the garden go back to lawn (not enough time right now to give it proper attention anyway)? My rotation is about 2-3 years, depending on how much I want to chance things too close to the walnut.

Have you ever tried the soil solarization for disease control? I'm thinking that as far north as we are (I'm in Iowa) that it might require letting 1 bed be solarizing for 1 year, or plant very short season crops either before/after solarizing.

CHRIS said...

thank you so, so much for your post. i found it really interesting and helpful. you completely answered my questions about crop rotation in the home garden! and then some! i hadn't expected an entire post about them! thank you!
on that note, everything you said makes so much sense. funny how most of the literature out there... or at least what i have been reading the last few years... seems to not make these points clear. instead, they all highlight the necessity of crop rotation even for the home gardener and without adding any of the points of consideration that you do. i can see how, in a perfect world where we all had gardens that were perfectly sized to our growing needs and perfectly orchestrated rotations, this "blanket" advice would not be an issue regardless of how effective/or not it really was. unfortunately, however, i imagine many home gardeners are working with some limitations and perfect crop rotations just add a whole other layer of complexity that can be tough to plan for. i know they have been for me in my garden each year. so thank you for explaining what those writers didn't!
now i really can't wait to start planning this year's garden beds. i'll be looking at how to arrange everything quite differently thanks to you and your butternut! lol!

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Joe said...

For me, the four beds that contain the roots, Tomatoes/potatoes, brassica, and greens get rotated. Peas don't rotate because their bed gets partially shaded once the trees fully leaf out, so none of the warm-season crops like it much. Beans, pumpkins, and corn haven't rotated in the past due to their layout being optimal for my space available, but I'm going to rotate them this year as I've had yield issues the past two years with the pumpkins and corn.

Potatoes are definitely important to rotate. Last year my father-in-law overlapped where he planted potatoes with where he had planted them the year before. When I visited him in July, you could clearly see where the overlap was by how poorly the plants were doing in that area!

Heather said...

Thanks for your advice. I didn't rotate my tomatoes one year because I changed my rotation plans and ended up with a bad case of blight. Won't do that again. (Plus I read not to compost store-bought tomatoes because they can spread blight. So I stopped doing that, just in case.) Generally, I rotate my raised beds like this (but I still tweak things now and then, and add other minor crops to these main ones): Year 1 is cukes and cabbage family. Year 2 is tomatoes/peppers. Year 3 is legumes. Year 4 is zucchini. Year 5 is tomatoes/peppers. Year 6 is garlic/onions. Year 7 is compost and letting the bed rest (a biblical concept). I try to keep two years between planting plants in same spot. It's still a work in progress. But it's fun work.

Unknown said...

I have four 4x8 raised beds creating one long fenced in area. This was the best spot in my yard. This is my 10th year gardening and I have pretty good luck keeping my summer squash, asparagus and tomatoes in the same place every year. Bed 1 - summer squash, cucumbers, and asparagus. My theory is that once the asparagus is just about finished, the squash and cucumber vines have room to take over. Bed 2 - Mix and match (peppers, beans, beets, lettuces, pak toy, arugula Bed 3 - Tomatoes, basil and arugula, Bed 4- Another mix and match bed - carrots, leeks, peppers, spinach, broccoli. So i guess I follow crop rotation in beds 2 and 4 but not with any special schedule.