Cabbage, Broccoli, and Aphids! Oh My!

With fall comes cabbage. I get so excited every year when switching to fall season at the prospect of planting all the delicious brassicas for me to eat throughout the winter. Cabbage, cauliflower, broccoli, kale, bok choy, tat soy, chards, turnips, collard greens, and so many more; these vegetables are all so delightful to cook and look gorgeous in the garden. The brassica family includes standard vegetable groups like cabbages, mustard plants, and cruciferous vegetables, but also incorporates some wild varieties and weeds. I will mainly discuss our common garden vegetables and how best to take care of them during the growing season. 

Heads of organic broccoli beginning to bloom in the garden.

A plot of red cabbage beginning to ‘head’.

Although you can enjoy multiple harvests of kale, collards, chards, bok choy, and mustard greens throughout the fall and winter, you will only get one harvest of vegetables that ‘head’ such as cabbage, cauliflower, and broccoli. One cabbage plant equals one head of cabbage, so we must make room to plant as many as we desire, but it also requires great care to ensure we still get that one harvest. Just as fall brings cabbage, cabbage brings aphids. 

Beautiful bok choy plants (a.k.a. Chinese cabbage) covered in mulch to assist in growing during the fall season.

Large bunches of Lacinato kale companion planted with flowers.

Aphids are tiny little pests that live mostly on stems and undersides of leaves on a variety of garden vegetables. They reproduce rapidly, come in almost every color imaginable, and love everything from tomatoes to broccoli to beans. In the case of brassicas, they are particularly ruthless. I have seen entire beds of kale and chard get overtaken by these annoying little critters, and seen beautiful developing cauliflowers eaten away due to a rampant aphid infestation. Sometimes you can do everything you can to get them to go away, and yet, you still lose some plants to these small militaristic bugs. Here are some tips on preventing aphids from bringing down your crops this fall.

Black bean aphids (a.k.a. blackflies) nesting on the underside of a bean leaf.

Green aphids that are difficult to spot on the underside of a leaf.

First of all, have every possible product and strategy ready to go at a moment’s notice: a garden sprayer for organic insecticides, a large bottle of safer soap and neem oil, sticky tape, a hose attachment with different pressure options, a bag of diatomaceous earth, and even some flour in your cupboard. Being prepared for aphids and other pest infestations is the first line of defense. Next, make sure to consistently check your plants for any possible signs of damage or pest presence. Aphids, in particular, are sap-sucking bugs, meaning watch out for leaf curl, chlorosis, stunted growth, misshapen fruit or crops, or even mold-like substances. Aphids will almost always hang out on the backside or underside of a leaf, so make sure to check there every day or two while looking for little sap trails on the plants as well. If a plant is too far gone, remove it from your garden immediately to protect your other plants (aphids only live on living plants, therefore pulling a plant and tossing it in city compost will kill all the aphids along with it.) So what to do if you find these guys on your plants? 

Using a hard jet of water on your plants to wash away aphids.

A woman gardener spraying plants with a mixture of organic insecticide and water to alleviate pest infestations.

I always recommend the first line of defense of straight-up hosing them off your plants. If your plants are established and strong enough to handle some hard jets of water, wash those suckers off! After a nice hose down, take your sprayer and insecticides like safer soap (or you can use a few drops of dish soap) and spray down your plants, ensuring that you soak the undersides of leaves or wherever the aphids are hanging out. I have found this two-step process to be pretty successful in ridding my plants of an infestation, however, there are other useful strategies as well! You can dust your plants with flour (which constipates the aphids, but only try this method if you can consume flour), or you can use Diatomaceous earth (DE) but only apply when your plants are in their earlier growth stage, never while plants are blooming. Now that you are equipped with the know-how of eliminating aphids, what can you do to prevent them from infiltrating in the first place?

Ladybugs attacking and eating aphids that have infested a garden plant.

Encourage beneficial insects like ladybugs, lacewings, parasitic wasps, and even certain spiders that will feed on aphids and other nasty pests. Spraying fruit trees with products like neem oil while in their winter dormancy will help kill any potential aphid eggs waiting to hatch in spring. Planting catnip, garlic, chives, marigolds, dill, fennel, or cilantro amidst your brassicas and other vulnerable crops can help deter aphids from nesting. Ultimately, even with all of these helpful strategies under your belt, the best preventative measure in ensuring a healthy season for your brassicas is awareness. Being aware of how to apply pest control in an organic way that helps the rest of your garden continue to thrive is the best strategy to use. Being attentive to your plants and watching their backs during their growing season is your greatest weapon. The earlier you find a possible pest infestation, the sooner you will be able to alleviate it. Remember that at the end of the day, even if you have to pull a few plants that are too far gone, you are doing what is best for your garden as a whole.