Growing Brassica

Vegetables from the brassica family have found their way into our diets as ‘go-to’ staples when preparing dinner.  These interesting and intensely coloured vegetables are quick and easy to prepare, with interesting flavour. The official scientific name is brassicaceae, however they are often referred to by an older name Cruciferae – apparently named after their cross shaped flowers.  

There are many different varieties of brassica:  cabbage, cauliflower, kale, broccoli, brussels sprouts, kohlrabi, turnip, rocket, radish, many Asian greens and even mustard and rapeseed (grown for its oil). There are also ornamental varieties with lovely flowers or foliage and some that grow as weeds. 

Brassica are easy to grow from seed. However, they need to be kept well-watered their entire lives as they will remember a period of drought. Even if this drought occurred as a seedling, mature plants can bolt to seed without developing the desirable edible stage. Brassica grow best in mild to cool climates and tolerate frosts well. A frost can even sweeten the crop as the plant produces more sugars to protect the cells from the harm of being frozen. Having said that, there are varieties that will do best in summer so make sure you grow your crops in the season that suits them best. 

Brassica like to grow in a free draining fertile soil with plenty of well-rotted organic material that is not too acidic. Add lime to improve the environment for them, if required. You need a pH of around 6.5 to 7.5. Brassica also like a firm soil, so while it is not recommended to walk on the prepared soil for most crops, doing the gardeners shuffle by lightly but firmly treading across the soil will give you a better result come harvest time.

The plants can grow rather large and have recommended planting distances of half a metre or more. Having said that, planting cabbages closer together can result in smaller, more manageable-sized cabbages.

Brassica don’t encounter too many problems during the growing season, although they can be severely damaged by the Cabbage White Butterfly, whose caterpillars can strip a seedling in a day. They can also fill a cabbage with holes and hide deep within a broccoli, only to be discovered upon cooking. You can avoid this pest by putting a net over the crop to exclude them, or spray with a food-safe insecticide designed to control caterpillars.

Another serious problem that can cause stunted growth with brassica is a soil-borne disease called Club Root that can build up to problematic levels in soil where the crop is planted in the same place every year. Once you have this disease in your soil, you will be unable to grow brassicas there again for 25 years or more, so it is very important to practice crop rotation with this group of plants in your garden.

Brassica have a long history, with a mention in China as early as around 4000 BC. It wouldn’t have taken long for brassica to spread through Europe, and from there across the world with the explorers and colonisers to become the globally popular crop it is today. The ancient Greeks had several varieties of cabbage, and the Celts also had them growing in a domesticated setting (although it is suspected these would have been a leafier variety, as the first documented round cabbage we would recognise was from 14th century England). Thomas Jefferson, a founding father of the United States and also a keen gardener was said to have imported broccoli seeds from Italy to plant in his garden in 1767.

The wide variety of brassica can be attributed to the fact they easily cross pollinate with each other. When desirable versions occurred like the leafy heads of the cabbage, the tasty flower buds of the broccoli or the swelled root of the turnip, they were bred by growers over the centuries to retain and improve these differences. Some say it was the Romans who first embraced this breeding programme to improve the varieties, while other variations were the result of the plant becoming inbred in more isolated environments. For example, the calabrese broccoli is named after its origins in Calabria in Southern Italy.

With such an extensive history, it isn’t surprising that many myths and ‘cures’ arose around the brassica family. The ancient Chinese believed cabbage could cure baldness, babies were said to be found “in the cabbage patches” and for some reason the famous baseballer Babe Ruth kept a cabbage leaf under his cap. However, the brassica family can benefit you in more sensible ways as a nutrient-rich crop with a very high concentration of Vitamin C among many other vitamins and minerals. It is claimed that one cup of shredded cabbage has 190% of the daily recommended dose of Vitamin C.

Brassica are such a versatile crop to eat, and can be prepared in many ways. Raw, steamed, stewed, sautéed, pickled and fermented are all good ways to try. Some people can find brassica bitter, due to a bitter tasting compound within the plant that some people can detect, and others can’t. A study has shown that children can often identify this compound when young, but as their taste buds mature, they may no longer taste it. So, if you struggle to get your children to eat their greens, it could be that they just don’t taste nice to them. Also, if you haven’t tried brussels sprouts since you were young (and hated them), give them another go - you may be pleasantly surprised to find out that you now enjoy them.

The bitter compounds can emerge if not stored correctly or if the plant is passed its best when harvested and was beginning to bolt. Most brassica can be kept dry and wrapped in plastic in the fridge for 2 or even 3 weeks. Broccoli is the exception, and doesn’t last long once harvested. Keep broccoli in the fridge and use it within 5 days to retain freshness. If you grow your own cabbage, harvest them with a long stalk and the outer leaves trimmed. Store them in a cool, slightly damp location for 3–4 months or even longer, checking often for signs of rotting.