Plant of the week: Broccoli

Got milk?  How about broccoli instead?  Broccoli has as much calcium in it as the equivalent weight in milk, plus it contains phytochemicals, folic acid, phosphorous, fiber, calcium, iron, and vitamins A, B2, B6, and C.  Plus, it’s delicious.

Ideal growing conditions

Broccoli is a cold weather plant, which means it is generally grown in the spring and/or fall, and timed so that it matures when the weather is cool.  If exposed to too much heat, it will bolt and produce a showy array of pretty yellow flowers.

Start broccoli indoors 4-6 weeks before the last frost date, then transplant the seedlings into rich, slightly acidic soil that retains water and gets at least 6 hours of sun.  Space the seedlings at least a foot apart.

Broccoli is prone to several pests such as cabbage worms and aphids; place floating row covers over your plants to protect them.  It can also be grown in very large containers — 5 gallons or larger is best.

Broccoli tolerates frost and can live in temperatures as cold as -12 Celsius.  Its growth is accelerated after a frost.


  • Calabrese broccoli is the kind of broccoli you see in the store.  It’s named after the Italian province of Calabria, where it was first grown.  Its stalks are topped by a compact head containing clusters of green florets.
  • Sprouting broccoli has multiple small green or purple heads that branch of its main stalks.
  • Chinese broccoli, or gai-lon, is smaller and darker than western broccoli.  It doesn’t produce heads; the whole plant is eaten, including the flowers.  The flavour is stronger and may be bitter.
  • Broccoli rabe, or rapini, is actually a separate species.





Harvesting, using, and preserving

Cut broccoli heads before the flowers have opened, when the individual buds are the size of pin-heads, dark green or purple-tinged, and tightly closed.  Cut them in the morning before it is hot.

After the main head has been harvested, the plant may grow more heads on side-shoots.

Broccoli can be refrigerated for up to a week, or blanched and frozen.  It’s delicious when lightly steamed, eaten raw, or added to soups and dishes.



  • Beets
  • Carrots
  • Celery
  • Chives
  • Cucumber
  • Dill
  • Garlic
  • Lettuce
  • Onions
  • Potatoes
  • Spinach


  • Beans
  • Peppers
  • Squash
  • Strawberries
  • Tomatoes

Fun facts

  • Thomas Jefferson brought broccoli to America; he imported broccoli seeds from Italy to America and planted them in his own garden in 1767.

Protecting brassicas from cabbage worms

If you are growing cabbage, Brussels sprouts, broccoli, cauliflower, kale, radish, turnip, or rutabaga, you may need to take steps to protect your plants from cabbage worms.  These green caterpillars love to chow down on brassicas and similar plants; after they pupate, they emerge as small, cream-coloured moths (that have a couple of dark spots on their wings).

There are many natural ways to control them, such as attracting their predators into your garden.  One simple solution is to construct a cover made of tulle (a fabric commonly used to make prom dresses and the like).  This fabric mesh allows in rain and sunlight but prevents moths from entering and laying their eggs.

You don’t need to make anything fancy.  You can make a wire hoop frame, or simply set up some stakes that you can drape the fabric over so it does not sit on the plants (as I have done above, on my hail-damaged plants).  Place something heavy on the edges of the fabric, where they rests on the ground.  Or, you can construct something permanent.  There are plenty of ideas on the internet.

For more information on cabbage worms, and other methods of controlling them, see

Direct sowing cool season crops

Once the snow has melted, and the soil is workable (that is, it is neither frozen, cold, or very wet), you may direct sow cool season crops.  These plants tolerate overnight temperatures that hover around the freezing mark, and even a touch of frost; they prefer the cool temperatures of spring and fall rather than the heat of summer, during which they may bolt (go to seed too quickly).

Refer to the seed package to see how many weeks prior to the last frost that you may sow the seeds.  The package may also list an ideal soil temperature.  You may choose to place row covers over the area that you are planting to expedite the warming of the soil and protect your plants from occasional cold nights.

The following plants are quite hardy, and can tolerate a soil temperature of around 5°C:

  • Leeks
  • Peas
  • Radishes
  • Spinach, lettuce, collard greens, kale, kohlrabi, and other greens
  • Sunflowers
  • Turnip and rutabaga

The following plants are also quite hardy, though they prefer a slightly warmer soil temperature of around 10°C:

  • Broccoli (shown above), Brussels sprouts, cauliflower, and cabbage
  • Beets
  • Carrots
  • Chard
  • Kohlrabi
  • Onion sets
  • Potatoes
  • Parsnips

The great zupumpkin!

In one of my first small gardens, I planted a pumpkin plant and a zucchini plant next to each other.  I didn’t save any of their seeds, but the next year, when I spotted a pumpkin plant coming up from the compost, I let it grow.  It started out looking like a bit like an elongated pumpkin or some sort of squash.  Then it ripened to the above specimen, which was christened the zupumpkin.


Cross-pollination occurs when an insect or the wind carries pollen from one variety of plant to another.  The resulting seed, when planted, sprouts a hybrid of its parents.  Since zucchini and pumpkins are both varieties of the same species, they can create the zupumkin (or zumption or pumcchini–your choice) but a cucumber and squash can’t procreate because they’re different species.

Cross-pollination does not affect the current year’s crop, but rather the next year–with one exception: corn.  If the pollen from the tassels of one variety of corn are blown into the silks from another variety, the cob that develops is a hybrid.

Self-pollinating plants

Vegetables like beans, peas, peanuts, eggplant, peppers, lettuce, and tomatoes are self-pollinating. Their seeds will produce plants like the parent, but insects will occasionally cross them, so if you want to be absolutely certain that your seeds will grow true to type, plant each variety at least 10 feet apart.

Insect- and wind-pollinated plants

Vegetables that are pollinated by insects or wind need to be separated by variety, and grown a distance apart (the distance varies with each type of plant).   To ensure that your seeds grow true to type, grow one variety of each type, or separate the different varieties.

Vegetables that willingly cross-breed

The following plants or plant families are prone to cross-pollination.  If you are planting them with the intention of keeping their seeds, keep varieties well separated.

  • Beets and Swiss chard
  • Cauliflower, cabbage, kale, Brussels sprouts, kale, collard greens, and broccoli
  • Corn
  • Cucumbers
  • Honeydew, cantaloupe, and other melons, excluding watermelons
  • Peppers (hot and sweet)
  • Squash (some varieties)
  • Zucchini and pumpkins