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Choy sum is a leafy green member of the cabbage family. Also known as Chinese flowering cabbage, its name means “heart of the vegetable”. It is a common ingredient in Chinese and Japanese recipes, and you can grow it at home.  Choy sum plants (Earth100) CC BY-SA 3.0 Choy sum description Choy sum (Brassica rapa var. parachinensis or Brassica chinensis var. parachinensis) looks a lot like bok choy but has longer stems. It is somewhat more tender than Chinese broccoli, making it an excellent choice for sit-fry. And there is even a purple variety!  Purple choy sum (Earth100) CC BY-SA 3.0 While choy sum can be perennial, it is grown primarily as an annual.
Unlike its cousin the cabbage, choy sum does not form a head. Instead, it grows in a loose cluster of leaves with bright yellow flowers. Plants grow 4 to 16 inches (10-40 cm) tall and have a shallow rooting system (4-5 inches deep), making them an excellent choice for container planting. You will want to use containers that are 6-8 inches deep and wide. How to grow choy sum Like other members of the cabbage family, choy sum prefers cooler weather. Temperatures of 55-75°F (13-24°C) are ideal. If you live in an area with hot summers, choy sum makes a nice winter crop. Plus, you can always grow it indoors on a windowsill. Choy sum seeds are contained in siliques. If you’ve ever let radishes go to seed, you’ll know what I mean when I say one plant can lead to a lifetime supply. You can also buy seedlings. [Check out your local farmers market or Master Gardeners plant sale.] If you use seeds, plant them ¼-½“ (.6-1.3 cm) deep and 2” apart. When seedlings are 2-3” tall, thin them 6” apart. Choy sum prefers a soil pH of 5.6-7.5 and at least 4-6 hours of sunlight each day. Feed your choy sum with a balanced fertilizer every 2-3 weeks. These plants grow quickly. Your choy sum should be ready to harvest in 30-50 days, when it is 6-8” (15-20 cm) tall. You can snip off outer leaves as you want them, allowing the inner leaves to continue growing, or harvest the entire plant. Rather than pulling it up by the roots, it is better to cut the plant at or slightly above soil level. This provides important soil microorganisms the food and protection they need to help the next seeds you plant. You can extend your harvest season by planting seeds in succession rather than all at once. Choy sum pests and diseases Aphids, caterpillars, and flea beetles can be managed with insecticidal soap or neem oil, but these plants are generally pest-free. Most diseases associated with choy sum are related to overwatering. Root rots and other fungal diseases, such as Verticillium and Fusarium wilts, can be avoided by watering at ground level and allowing the soil to dry slightly between waterings. Bacterial wilt may also occur. Choy sum is yet another edible plant you can add to your landscape, garden, or balcony. Give it a try today! Adult and larval vegetable weevils are primarily night feeders.  Vegetable weevil (Clemson University - USDA Cooperative Extension Slide Series , Bugwood.org) CC BY 3.0 Before we dive into the world of weevils, let me explain that there is some confusion about vegetable weevils. There are actually two species in question: Listroderes difficilis Germain is the true vegetable weevil, native to South America and now found globally. The other vegetable weevil, Listroderes costirostris, is currently only found in California and western Arizona. Of course, that may change as these garden pests take advantage of our changing climate and increased global trade. For the sake of our discussion today, we are talking about the true vegetable weevil, though the information is just as relevant to both species. Either way, if you know what to look for, you will be better able to prevent problems from getting worse. Vegetable weevil damage Your first clue of a vegetable weevil problem may be plants cut off at ground level. Adult weevils often girdle stems close to the ground. You will also see feeding holes in leaves. Those holes start out small and round, but eventually expand into larger, irregularly shaped holes.  Vegetable weevil larva feeding on tobacco (R.J. Reynolds Tobacco Company, Bugwood.org) CC BY 3.0 While they can fly, they almost never do, so crop damage is usually first seen around the edge of a garden. These pests feed on the buds, leaves, and roots of several garden crops, including beans, beets, cabbage, carrots, cauliflower, collards, lettuce, mustard, onions, potatoes, radish, spinach, Swiss chard, tomatoes, and turnips. As they feed, they create places where other pests and diseases can take hold. Vegetable weevil description Vegetable weevils look very similar to carrot weevils. They are small (0.38 inch/1cm), bristly, tan to grayish brown snout beetles with elbowed antennae. If you look closely, you may see a V-shaped spot on their wingtips, though that marking can fade over time. [One easy way to catch many insects for a closer look is with a loop of packing tape wrapped around your fingers, the same way you collect pet hair off that favorite sweater. Insects have not evolved a defense against packing tape, and it gives you a relatively clear view without the hassle of trying to chase your specimen around with a magnifying glass.] Vegetable weevil larvae start out as pale, C-shaped grubs with dark heads. As they feed, they turn green and stretch out. They are about the same size as the adults. Eggs are yellowish white and often laid on plant stems. Vegetable weevil lifecycle Vegetable weevils are parthenogenetic, which means females reproduce without assistance from males. According to the Virginia Cooperative Extension, “males are not known for this species.” Some of those lady vegetable weevils can live for two years. They overwinter in plant debris and weeds. In summer, as temperatures rise, they lay low in the weeds in a behavior known as aestivation. Vegetable weevils often hide in the soil, so raking the soil after harvest exposes eggs to predators. [My hens always loved it when I gave them a freshly harvested bed to play in!] Vegetable weevil management
The best way to deal with vegetable weevils is with diatomaceous earth (DE). This ultra-fine powder blocks the air holes in a weevil’s exoskeleton. Apparently, they don’t like it on their feet, either. Since they rarely fly, you can often keep these pests off young plants with row covers. Crop rotation, neem oil and other insecticidal soaps, sticky barriers, spinosad, and a bevy of birds and beneficial predators will also help you keep vegetable weevils from doing too much damage in your garden, but diatomaceous earth is your best bet. Did you know that startled vegetable weevils play dead, falling from the host plant when disturbed? Now you know. |
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