My Kohlrabi Experiment: From Veggie Patch to Caterpillar Haven
As a backyard gardener always up for a bit of experimentation, I decided to try my hand at growing kohlrabi this season. Known for its quirky, bulbous stems that taste like a cross between cabbage and broccoli stems, kohlrabi (Brassica oleracea var. gongylodes) seemed like a fun addition to my plot. But what started as a simple test of growing conditions has evolved into an unexpected wildlife observatory, complete with a bustling encampment of hungry caterpillars. Let's dive into the details of this ongoing adventure, including why I chose partial sun, the surprise visitors, and my decision to let nature run its course—even as the calendar flips to August 8, 2025, and cooler weather looms.
Setting Up the Experiment: Kohlrabi in Partial Sun
Kohlrabi isn't as finicky as some veggies, but it does have preferences that make it ideal for experimental gardening. Traditionally, brassicas like kohlrabi thrive in full sun, but in hotter climates or during peak summer, too much direct light can cause bolting or bitter flavors. Drawing from gardening wisdom, I opted for a spot with about 50% sun exposure, think dappled shade from nearby trees or morning light followed by afternoon reprieve. This setup mimics the plant's natural preference for cooler conditions, potentially leading to sweeter, more tender bulbs.
I planted the seeds in early spring, spacing them about 6-8 inches apart in well-drained soil enriched with compost. By midsummer, the plants had developed their signature swollen stems, and a few were even harvest-ready. The partial sun seemed to work wonders: The leaves stayed vibrant and green without scorching, and the bulbs grew steadily without the stress of intense heat. It was a low-stakes trial, after all, kohlrabi is forgiving for beginners, and I wasn't banking on a bumper crop. Little did I know, my modest patch was about to become a hotspot for some uninvited guests.
The Arrival of the Caterpillar Encampment
Fast-forward to late summer, and my kohlrabi leaves started showing signs of nibbling. Irregular holes appeared, edges chewed ragged, and small black specks (likely frass, or caterpillar poop) dotted the foliage. Peering closer at the image I captured, there they were: several green caterpillars, blending seamlessly with the leaves, munching away like tiny leaf-vacuuming machines. One prominent critter curls on a upper leaf, while others hide in the crevices, turning my experiment into what feels like a full-blown caterpillar encampment.
Based on the appearance, smooth, green bodies about an inch long, these are likely imported cabbageworms (Pieris rapae), the larval stage of the common cabbage white butterfly. These pests are notorious for targeting brassica family plants, including kohlrabi, cabbage, broccoli, and kale. The adult butterflies, small and white with black spots, lay eggs on the undersides of leaves, which hatch into these voracious eaters. Other possibilities include cabbage loopers (Trichoplusia ni), which are similarly green but move in a distinctive inchworm-like loop, or the smaller diamondback moth caterpillars (Plutella xylostella). Regardless, they've set up shop, feasting on the foliage and leaving behind a lacy skeleton of leaves. There are quite a few, maybe a dozen or more across the plants—turning my kohlrabi into a buffet.
Since this was an experiment anyway, I'm not sweating the damage. The bulbs are still forming underground (or rather, at the stem base), and kohlrabi's edible part isn't the leaves, so the harvest might still be salvageable. Plus, watching this unfold adds an educational twist: It's a front-row seat to ecology in action.
Letting Nature Take the Wheel: What Happens Next?
Rather than reaching for sprays or manual removal, I've chosen to leave the caterpillars be and observe their next moves. After all, they're just doing what caterpillars do, eat, grow, and transform. In a typical life cycle for imported cabbageworms, these larvae will continue feeding for a couple of weeks, molting several times as they bulk up. Once fully grown, they'll seek out a sheltered spot (perhaps on the plant stems, nearby fences, or even the wooden border in my garden) to spin a silken cocoon or form a chrysalis. From there, they'll pupate, emerging as adult butterflies in about 1-2 weeks under warm conditions.
But timing is everything, and with fall approaching, these little guys better hurry. In many regions, late-summer generations can complete their cycle before the first frost, but if temperatures drop too soon, the pupae might overwinter in diapause, a dormant state, until spring. The catch? Their food supply is dwindling as they devour the leaves, and kohlrabi isn't evergreen. If they run out of munchies, they might move on to nearby plants or starve, disrupting the cycle. Plus, predators like birds, wasps, or even beneficial insects could swoop in for a snack.
I'm rooting for them to make it to butterfly stage and fly off, it's a reminder of the interconnected web of life in the garden. This "encampment" could even benefit the ecosystem by attracting pollinators later on. If things get too dire, I might intervene with a gentle relocation, but for now, it's hands-off observation.
Lessons from the Patch: Embracing the Unexpected
This kohlrabi experiment has taught me plenty: Partial sun works well for steady growth, but gardens are rarely pest-free zones. Turning a potential problem into a learning opportunity has been the real win, watching caterpillars transform could be more rewarding than a perfect harvest. For fellow gardeners facing similar invasions, consider companion planting with marigolds or nasturtiums to deter butterflies, or use floating row covers early on. But if you're like me and enjoy the surprise, let it ride and see what unfolds.
As the season winds down, I'll keep an eye on my caterpillar crew. Will they cocoon in time? Will the kohlrabi bulbs survive the siege? Stay tuned, nature's got the script, and I'm just along for the ride. If you've had similar garden guests, share your stories; experiments like this are what make gardening endlessly fascinating! But, I think at least one Bluebird has spotted them and is moving in for lunch, as an FYI. Plus you can tell that the white butterfly that hangs about is laying eggs all over the place constantly, I just let them be as this was a simple experiment. If I plan to grow a decent batch of kohlrabi I will have to net them off or something similar.
