Growing Broccoli for Better Health

14 February 2014, written by Barbara Pleasant

Fifty years ago when I was a kid, broccoli was an exotic vegetable reserved for special dinners. My brothers and I got excited when we had "trees" on our plates, never mind that the limp, pale stalks came frozen in a box. Years later, when I grew my first crop of broccoli, I was amazed at its tender succulence, which was like nothing I had tasted before. Recently I recalled this revelation after cooking some organically-grown broccoli from the store, which was so tough it was barely edible. This was not the farmer's fault. When broccoli is imperfectly stored, it converts its sugars into tough, chewy lignin.

This never happens when you grow your own broccoli and harvest it and eat it on the same day. If this is a first-time experience for you, discovering the luscious, melt-in-your-mouth quality of garden-fresh broccoli may make you drop your fork. It's that good! And, because fresh garden broccoli cooks in a flash, it is amazingly good for you, too.

Broccoli and Sulforaphane

In health news, 2013 was a big year for broccoli. One study found that eating broccoli and other sulforaphane-rich veggies can help prevent osteoarthritis, which affects one in five people over the age of 45. Sulforaphane may also help prevent cancer, but only if the broccoli is fresh and minimally cooked. Heat-processing destroys an essential enzyme that activates broccoli's health-promoting properties; frozen broccoli that is re-cooked in a microwave provides little or no sulforaphane activity.

Fresh, garden-grown broccoli, however, is so tender and fast-cooking that the two cooking methods known to preserve broccoli's sulforaphane levels, steaming for less than five minutes or submersion in 57°C (135°F) water for 13 minutes, would give overcooked results. In my experience, two minutes of steaming is about right for bite-size broccoli florets fresh from the garden. This method has been found to preserve broccoli's powerhouse of heat-sensitive nutritional compounds.

Growing Broccoli for Fresh Eating

I no longer attempt to grow a freezer crop of broccoli, because here we have a vegetable built for fresh consumption. A few extra heads do get steam-blanched and frozen, but nowadays most of my broccoli goes from garden to table within a few hours. Changing broccoli to a crop meant for eating fresh has brought changes to my planting plans, and to the mix of broccoli varieties I grow in my garden.

For example, I used to set out about a dozen broccoli plants in early spring, using cloches to get them through the last bouts of cold weather. Now I stretch out the planting times, setting out groups of four plants two weeks apart, to keep the plants from bearing all at once. In midsummer, I succession crop the broccoli I grow for fall, too.

In terms of broccoli varieties, I still like to use a fast-maturing "Calabrese" broccoli hybrid known to produce big heads (such as 'Arcadia', 'Belstar' or 'Bay Meadows') for my earliest plantings, mostly because they do so well. Then I switch to a sprouting type for the broccoli plants that will bear into summer. These varieties produce a small primary head followed by about 20 tender side shoots (small broccoli heads) over a period of several weeks. If you want cut-and-come-again broccoli on the table for a long time, it's hard to beat the 'Green Magic' variety, which has earned a RHS Award of Garden Merit in Great Britain and Texas Superstar status in the USA.

Tips for Growing Broccoli

I covered the basics in terms of timing in How to Grow Better Broccoli, after which readers asked important questions. Many gardeners are frustrated when their plants "button" – produce one tiny head and nothing more. This happens when the young seedlings are stressed by cold temperatures or cramped roots, or are too old when they are planted out. You are not likely to see this problem at all if you grow your own seedlings and set them out when they are four to five weeks old.

In many locations, broccoli seedlings need protection from cutworms, which hide in soil and mulch during the day, and girdle young seedlings at night. I use rounds cut from plastic drinking cups, pushed into the ground at transplanting time, and I never lose a plant.

Finally, it is never good to let heads sit in the garden too long, which some gardeners do in hopes that the heads will get bigger. At the first hint that the beads are not as tight as they were the day before, the head should be cut. Wait too long and the beads will turn into flower buds if they manage to escape infection from various bacteria that cause brown spots of rot. Another way to forestall this tragedy is to use a clothespin to pin together three large top leaves over the growing head, forming a leafy umbrella that helps keep the head dry and shields it from excessive sun. But like juicy homegrown tomatoes, tender, garden-fresh broccoli is worth a bit of extra trouble.

By Barbara Pleasant