Jane McLeod: Cold doesn’t deter broccoli
May 15, 2011
Steamboat Springs — Long, cold springs; cloudy, cool summers; or short, crisp falls — with one or all three, there's broccoli.
The vegetable prefers a cool growing season. If temperatures consistently climb to blistering hot levels, it will bolt into flower stalks that bloom and go to seed before gardeners can pick them.
Because of broccoli's aversion to high heat, it is planted in climates similar to Northwest Colorado in early spring so that it will mature before much of summer's heat.
Usually, broccoli is grown from seedlings transplanted into a garden. When the seedlings are 5 to 6 inches tall, or six to seven weeks old, they can be set out, two or three weeks before the last expected frost. The seedlings will tolerate a frost, but not a hard freeze. If a freeze is coming, cover the young plants and maybe even hold a few seedlings back to try again.
If gardeners sow broccoli directly into a garden and thin the plants later, they can be sown a month before the last frost.
When planting seedlings, space them 15 to 18 inches apart. Set them an inch or two lower in the ground than they were in their pots, firming the soil around them and watering them well.
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Keep an eye on nighttime temperatures and keep a sheet ready. Fertile soil allows for closer spacing, but too-close spacing will result in more side shoots and smaller main heads. Extra enrichment, such as fish emulsion, only is needed if you are trying to hasten maturity to beat the heat.
Basic ingredients for growing successful broccoli include fertile soil to begin, proper drainage but steady moisture, a good mulch to retain moisture and full sun.
Some shade only helps later in the summer heat, but gardeners also can add a shade cloth to retard bolting.
With a tree-like shape, broccoli plants, as vegetables go, don't use a lot of space. But the plant roots will spread, and although the plant itself will only reach a height of just more than 2 feet, it will produce a lot of broccoli.
After the big center cluster — basically, an immature flower head — is trundled off to the kitchen, side-shoots develop in the leaf axils that can be harvested, as well. Some broccoli varieties even tout that they produce lots of side-shoots.
Most varieties mature in about 60 days, but they must be harvested immediately or the center head, which will be smaller than seen in stores, will quickly open into yellow flowers.
This show of yellow flowers happens quickly and is slightly mortifying to a vegetable gardener, because it means that the plant's production is over and a feast of broccoli has been missed — so keep up with the picking.
Harvest broccoli by cutting the stalk or stem several inches below the head with a sharp knife.
A very rich source of vitamins and nutrients, broccoli has more to offer nutritionally than just about any vegetable we consume. Raw or cooked — but steamed, not boiled — the health benefits of broccoli are too many to mention.
But it's safe to say that it ranks extremely high on the list of best-for-you vegetables.
Jane McLeod is a master gardener with the Routt County Cooperative Extension Office. Call 970-879-0825 with questions.