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Interplanting Corn

You’ve probably heard of the Three Sisters Garden, where you plant corn, beans, and squash together for a symbiotic relationship that takes up less space for all three crops. But interplanting can work with other crops too.

This year, we decided to experiment with interplanting corn in with a sweet potato bed that won’t give up the ghost. Each year, despite pulling what we think is all the sweet potatoes, the crop keeps coming back, rendering a 4×4 bed unavailable for other crops…or so we thought.

Sweet potatoes return every year in our climate.
Sweet potatoes return every year in our climate.

Interplanting is a way of using the space between larger-spreading crops to grow small, quick crops. For example, planting radishes around watermelons or pumpkins early in the season will give you two harvests from one growing space without compromising the integrity of either crop.

Rather than giving up our growing space to sweet potatoes for the season, we opted to utilize the built-in living mulch to make a home for something tall. Corn seemed the obvious choice. The root system of the sweet potatoes only occupies a small section of the bed, but the leaves spill over the entire bed. Perfect!

So, we started seeds for corn in a deep seed flat.

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By doing so, we’d grow the corn to a reasonable height to bypass the shadow of our sweet potato patch. That worked like a charm.

Transplanted corn stalks reach past the height of our sweet potato foliage
Transplanted corn stalks reach past the height of our sweet potato foliage

To plant them out, we flipped as much of the sweet potato foliage out of the bed as possible. We used hexagonal (offset) rows for spacing on 12″ centers after amending the bed with good quality compost and organic veggie fertilizer. Then we wove the sweet potato vines back through the seedlings.

Corn interplanted with sweet potatoes.
Corn interplanted with sweet potatoes.

The whole process took less than 20 minutes after sunset one evening. So far so good! Here’s our cast of characters: Country Gentlemen corn and 3 types of sweet potatoes (whichever took root from last year’s stragglers) from Southern Exposure Seed Exchange.

So our sweet potatoes serve as mulch for keeping moisture in the soil while staying primarily out of the way of the corn’s root system. It’s a win-win situation. We’ll report back later in the season about the results.

This Post Has 19 Comments

  1. Mike S.

    This year I also am mixing sweet corn with sweet potatoes, I planted the corn in the typical rows, about three feet apart, then, after the corn sprouted and is growing, I set my sweet potato slips in every other row, so I can still harvest the corn without stepping on the vines, I hope. Later this week, I plan on putting some leaf mulch down between the rows. As I harvest the corn, I will cut the stalks back, unless the potatoes are climbing them.
    Just play it by ear and see how it goes.

    1. Christy

      Awesome, Mike. Keep us posted on how it goes.

      1. Olusoji

        I’ll like to hear from you

        1. Mike S.

          Growing the sweet potatoes between the corn has worked out quite well, I have been doing it for a few years now. This year I have planted Vardaman and Porto Rico, both bush varieties, hopefully the vines won’t take over outside of their desired area like they have in years past. Both the corn and the potatoes are happy and produce quite well.

          1. Christy

            Glad to hear it!

  2. Theresa M Hodge

    I am wanting to do intercropping in my garden this year I have a 30 x 70 garden I like to plant things that keep coming back like squash ,beans, etc. How ever I hear that you can plant corn let it get so high and then plant your melongs alone in between the rows is that so?

    1. Christy

      Yes, Theresa, you can underplant with melons or squash under corn. What you’re looking for is instructions for a Three Sisters Garden. Check this out for guidance.

  3. Deborah

    I love your idea of sweet potato in the corn. We have limited space and were woundering how to get them into our garden. I have another question though, would it work to plant corn, peas and gourds in the same plot?

    1. Christy

      Gourds usually need something to climb, so they may try to climb your corn, just like the peas, but if you let them sprawl it would probably work. Peas grow better in cooler climates in spring. We grow ours in the fall instead in Los Angeles because the weather is just too hot for peas once April hits. But your microclimate may be different so it’s worth a try if you have had success growing peas in spring where you live. I have found that beans often outgrow corn within a month, so have a couple trellises handy to help support vining crops around corn.

  4. Miriyam Glazer

    Wish I understood what you meant by “hexagonal” rows…it looks so cool!

    1. Christy

      Hi Miriyam,

      Let me explain hexagonal or off-set planting briefly. Imagine you have a grid. In the first row of that grid you plant corn in box 1, box 3, box 5 and box 7. In row two of that grid you plant corn in box 2, box 4, box 6. Then you plant row three in the same way as row 1. All plants are exactly the same distance away from each other. Does that make sense?

      1. Nelson sabbe

        In field corn the old planters used a “check row” system, giving the same spacing you discribe, that way the corn could be cultivated in two directions giving better weed control.

  5. Jennifer

    Well how did it go? the corn and sweet potato experiment? I am wanting to try the same thing.

    1. Christy

      UPDATE: It worked like a charm. We had a great corn harvest and filled 2 bushels with sweet potatoes. Can’t complain! Hope you try it for yourself.

      1. Jennifer

        Oh yeah so glad to hear that! I usually plant about 6 sweet potato plants in a 16 square foot area how many corn did you plant? do they self pollinate?

        1. Christy

          We average between 16-20 plants per 4’x4′ bed. I’ve seen it planted closer together, but with our heat, I wanted to make sure there was enough air circulation. If you plant in a block of at least 3×3 they will pollinate each other.

          1. Jennifer

            Thank you so much! I can’t wait. It seemed such a waste of vertical growing space to have all those vines on the ground and nothing growing UP. So corn or okra made sense to me to try. Okra seemed like it would be hard to harvest without damaging the sweet potato plants.

      2. Kasey

        I never have an issue getting my sweet potatoes out, do you think this would work if I planted my corn and sweet potatoes at the same time?

        Thank you.
        -Kasey

        1. Christy

          They occupy different root space, so it should work. But they are both heavy feeders so you need to amend your beds really well and feed them throughout the growing season to make sure you get a decent harvest of both.

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