Tips and Tricks for Brassicas (broccoli, cauliflower, cabbage, brussels, kohlrabi, kale)
Updated: Feb 21, 2021
The single species Brassica oleracea are en example of how breeding of a single species can result in several variations of plant. I love growing these cold hardy vegetables for use all year round.
I like to start my broccoli, cauliflower, cabbage and Brussels sprouts indoors to prevent loss to cutworm and other variables. Seeds for these plants are often expensive so I like to make sure each seed counts. I also like to space out my broccoli, cauliflower and cabbage sowings so they do not mature all at the same time. Days to maturity can vary widely according to variety you are planting, from 48 days to 120 days. I also find that variety you choose can be important in the success of your harvest, ask your neighbours what varieties they have success with and start there.
Brassicas have many companion plants including chamomile, dill, mint, rosemary and sage. These plants will attract beneficial predatory insects (so let them flower). Brassicas are NOT good companions to tomatoes, peppers, eggplants and other nightshades including potatoes. It is important to rest the soil between plantings of brassicas. Make sure you move this crop around each year in your garden to prevent diseases such as clubroot.
My favourite varieties of broccoli are Everest and Gypsy because they produce such large heads of broccoli, prolific side shoots, and are quick growing. They are also frost tolerant and hold up well during the heat of summer! Broccoli likes hummus rich soil and regular watering (for me regular watering is about 2" of water once per week in July and August). I always add some well composted chicken manure to the entire bed, a 1/4 cup of a balanced fertilizer like Gaia's All Purpose 4-4-4 and after transplanting the seedling 12-18" apart. I also tamp the dirt down around the base of the plant with my foot, a highly unusual thing for me to do as I normally would never step a foot near my dirt.
Your broccoli is ready to harvest before the flowerettes start to open but after the head is a little less dense. If you spread out your broccoli plantings you could have a large head of broccoli each week over a month long period (or longer). By the time you've cut your last broccoli head, the first planting should be producing lots of side shoots. If you cut the head of broccoli further down the stem you will end up with less side shoots but they will be larger. If you cut closer to the head of broccoli you'll get more side shoots but they will be smaller.
Cauliflower also grows very well here; my favourite varieties include Amazing and Snow Crown. I grow them similarly to my broccoli, but if you like the sweet nutty flavour and beautiful white colour of your cauliflower heads you need to keep them out of direct sunlight. There are several options for doing this. The simplest and my favourite method is to fold a couple of the large leaves and snap the stem so they stay in place shading the cauliflower head. Cauliflower do not send out side shoots so spreading out your plantings can be even more important with this plant.
Brussels sprouts like their space, well composted chicken manure and fertilizer when they are transplanted. They usually take much longer to mature, approximately 100 days! But again they are frost tolerant and like the cool weather. Do not add anything nitrogen rich to the soil after mid summer to produce the best brussels. Cut your brussels from the bottom up as they mature or if you'd like a plant to mature them all around the same time you can snip the top off and within a couple weeks they should all be ready to harvest.
Cabbage is surprisingly easy to grow! You can choose a variety like Consul and they hold well without splitting over a long period of time. Cabbage also does not produce side shoots, so the plant can be removed for something else or you can plug in a cover crop to rebuild the soil.
I would say one of my biggest challenges is that everyone likes to eat my brassicas, especially the cauliflower and cabbages! Slugs are a pest I keep an eye out for, along with the cabbage moths' offspring. If you're only doing enough plants for your family it is pretty easy to pick them off: slugs early in the morning and cabbageworms you'll find on the underside of the leaves. If cabbageworms become an issue, you can also cover your brassicas in a light floating row cover. This prevents the cabbage moth from laying it's eggs on your brassicas.