Bill Pitts is a freelance writer who gardens in DeLand.

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Friends or Foes?
by Bill Pitts       #Advice   #Sustainability and Self-Sufficiency   #Vegetables

While I consider French marigolds (Tagetes patula) an essential potager plant, some gardeners believe it is a bad companion for vegetables because it can attract pests, such as spider mites.

The “Three Sisters” is one of the most famous examples of companion planting. Pole beans, corn, and pumpkins are grown together on hills, and each of the plants helps the others. The corn gives the beans something to climb, while the pumpkins serve as a living mulch, keeping the roots cool and moist.

I find the three sisters get along best when I stick to varieties closest to those the Native Americans would have used. An heirloom field corn provides a sturdy support for beans, but when I tried a finicky modern sweet corn, the whole planting came tumbling down in a tangled mess, and these famously good companions became bad ones.

I have found that vegetables and herbs of different families make great companions, but bad ones if you are practicing crop rotation over a period of years.

Some plants will always make bad companions. I once saw roses (Rosa spp.) interplanted with Agave. These plants had completely different cultural requirements. The gardener could not keep the roses happy without making the agaves miserable, and vice versa. In the end, both suffered.

But usually I find the question of whether plants will make good companions more complicated. In the spring, a row of trellised tomatoes can provide shade for an underplanting of lettuce, preventing them from bolting as quickly, therefore extending the harvest. They make good companions. But the same relationship turns bad in late fall and winter, when the days are short. The lettuce needs all the sun they can get. That problem can be fixed easily enough: Plant lettuce south of the tomatoes in the fall.

If you practice crop rotation, mixing lettuce and tomatoes can create complications. Basically, crop rotation is planting to avoid growing vegetables and herbs of the same family in the same spot season after season. It’s a great way to reduce problems with pests, diseases, and nutrient deficiencies. But to practice crop rotation any length of time in a small home garden usually involves arranging plants according to family. If you pair lettuces with tomatoes, you have devoted that spot to both the nightshade family and the aster family. If you add carrots to the mix on the grounds that “carrots love tomatoes,” you’ve got a third family. It is easy to imagine how any crop rotation scheme could become muddled in just a year or two. Plants of the same family would wind up in the same spot one season after the next. Problems would ensue, and the lettuces and tomatoes would no longer seem such good companions after all.


Clockwise: Artichokes take up a lot of space, attract all sorts of pests, and don’t produce much, making them an all-round bad companion in the vegetable garden, but in my mind, they are still 100 percent worth it. • Artichokes take up a lot of space, attract all sorts of pests, and don’t produce much, making them an all-round bad companion in the vegetable garden, but in my mind, they are still 100 percent worth it. • I am still uncertain whether this foxtail millet made a good companion to my tomatoes, or for that matter anything else in the garden, but the birds enjoyed eating the seeds.

Perhaps try planting lettuce with sunflowers (Helianthus annuus). They belong to the same family, so the rotation scheme stays neat. The sunflowers will provide some shade in late spring. The following season the bed could be planted with vegetables of any other family, though gardeners who are serious about crop rotation believe that certain sequences are better than others.

Huauzontle, a delicious Mexican vegetable, introduced me to the technique of trap cropping and, through it, the discovery of many bad companions in the garden.

I once planted a bed of spinach, Swiss chard, and huauzontle, a delicious Mexican vegetable, because all belong to the family Amaranthaceae. I expected the chard to be devoured by worms, as it usually is in my garden. I expected the huauzontle to thrive because it is a vigorous half-wild plant, very similar to lamb’s quarters. But I was wrong. The worms all went to the huauzontle. They preferred it to the spinach and even the chard. I did not know it at the time, but I had stumbled upon a companion planting technique called “trap cropping.” Basically you protect one vegetable (the chard) by pairing it with something the bugs like even better (the huauzontle).

This experience led me to try other trap crops, and I soon learned that good companions can become bad ones in this area too.

For several years, stinkbugs were worse than usual. They would suck the juice from tomatoes, making hard discolored spots, which would eventually rot, ruining the fruit. Remembering the huauzontle, I turned to trap cropping as a solution. My plan was to lure the stinkbugs away from the tomatoes with things they like even more.

I read all I could on the subject and learned that stinkbugs love okra, sunflowers, and certain grains, such as sorghum. If I planted enough of these, the stinkbugs would leave the tomatoes alone. That was the theory. I told a gardening friend what I was up to and she gave me a stern warning: “You’re only going to attract even more bugs, and your tomatoes will be worse off than ever.”

Whether okra makes good companions for tomatoes may depend on the planting arrangement.

She was right. That spring the garden swarmed with stinkbugs. They feasted on everything indiscriminately, including the tomatoes. Wondering where I had gone wrong, I turned to a university specialist in trap cropping. He told me I should have planted a ring of sunflowers, sorghum, and other trap crops around my entire yard, with the tomatoes in the middle. I have not tried this yet.

Recently, I have been growing vegetables in containers, and one of the things I love about this way of gardening is that it gives me the freedom to mix things up. There is little need for crop rotation because some or all of the potting medium is replaced from season to season. I have found that when I plant all sorts of vegetables together, mixing up species and families, they find a harmony I could have never planned. The kale shades the lettuce, and both protect the even more delicate corn salad, and for whatever reason the kale is happier, too, suffering from fewer aphids than in the past.


A version of this article appeared in Florida Gardening Volume 23 Number 4.
Photography courtesy of Bill Pitts.


Posted: 07/03/18   RSS | Print


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