Gardening Tip of the Week – How To Grow Broccoli
Eat Broccoli for Exceptional Health Benefits
Broccoli has a long culinary history going back to the Romans but it wasn’t until recently that its exceptional health benefits were recognized. Florets and stems are packed with vitamin C and provide calcium, potassium, and iron. A single ounce of broccoli has as much calcium as one ounce of milk.
The 4-inch to 6-inch blue-green heads are delicious raw or cooked — much better than store-bought broccoli!
Fall is the best time to plant broccoli because it does best in cooler weather. While it prefers temperatures between 65º and 75º F, it can still germinate and grow in soil with temperatures as low as 40ºF. For North Texans, this means we can usually grow it all the way through the winter and into the following spring for a much longer growing season.
Broccoli seeds can be started inside and then transplanted, or directly sown into the ground.
When planting in the spring, make sure you start early enough that you can harvest it before the weather becomes too hot.
Varieties suitable for North Texas
There are several excellent varieties of broccoli that do well in our climate. One of the most common is Waltham 29, which is an heirloom. It grows prolific side shoots and is especially cold tolerant.
If you have eaten broccoli in Italy, you know why Di Cicco is superb. It produces numerous small to medium sized heads well into the summer for more delicious broccoli more often! We recommend harvesting the main head when it is 3 inches in diameter; this will encourage side shoots. Di Cicco is a good freezer variety, and leaves are also edible, cooked like chard. Seeds are excellent for sprouting!
Broccoli Raab is grown for its asparagus-like spring shoots. The tender stems, buds, and flowers have a wonderfully delicate and slightly bitter, spicy, and peppery broccoli flavor, which can be enjoyed in salads, stir-fried, or steamed. Budding shoots should be harvested just before the flowers open for best flavor.
Romanesco is not actually a broccoli, but somewhere between broccoli and cauliflower. It produces 5-inch to 6-inch heads. First noted by Italians in the 16th century, it has caught the eyes of gourmet chefs. Cooked, Romanesco has a delicious nutty flavor and a texture similar to cauliflower.
Summer Purple is a sprouting broccoli. Sprouting broccoli produces shoots (rather than one head) and is easier to grow than common broccoli. Unlike most other sprouting varieties, Summer Purple does not need a cold period to start production and it continues to produce in warmer weather. Fresh spears are beautiful on vegetable trays, and can be steamed or stir-fried for a tender, succulent, nutritious addition to any meal. Purple florets “magically” turn green when heated!
When to Plant
For spring planting, start seeds between February 3 and February 17 — approximately 4 to 6 weeks before average last frost (March 16). For transplants, you can wait a little longer, however, in spring, it’s especially important that your plants receive enough cool weather to “harden off.” Hardening off is the process of gradually introducing plants to the direct sunlight, dry air, and cold nights, usually by moving plants outdoors for a portion of the day.
For fall plantings, start seeds between August 15 and September 30. This gives them 85 to 100 days to produce before the average first fall frost (November 21). Transplants can be planted two to three weeks later from early September through mid-October.
Tip: Extend your harvest by practicing succession planting. Instead of planting your entire crop all at once, plant a few every couple of weeks.
Your seeds should begin to emerge 7 to 14 days after planting. Spring transplants can grow in as few as 6 to 8 weeks, and in only five to six weeks for a fall crop.
Where to plant
Broccoli requires full sun, although it will tolerate part shade. The soil texture should be between sandy and clay loam. Work in 2 to 4 inches of rich compost before planting.
How to Plant
Plant seeds 1/8 to a half inch deep, or set transplants slightly deeper than they were grown originally. Space your plants 12 to 24 inches apart. If row planting, allow 36 inches between each row.
When 2 inches tall, thin to 1 plant every 18 inches.
To help with seed germination, soak seeds overnight in a solution of liquid seaweed.
When transplanting, always work from wet soil to wet soil, preferably with liquid seaweed in place of plain water. Liquid seaweed is a fantastic an all-natural, organic root stimulator that also reduces the chance of transplant shock.
For best results, use Marshall Grain’s Organic Planting Recipe.
Care and Maintenance
If you notice the bottom leaves of your plants turning yellow, and the problem continues toward the top of the plant, your plants may need a high nitrogen (but low phosphorus) fertilizer. Blood Meal, with a ratio of 12-0-0, is a quick nitrogen fix for yellowing leaves.
One secret is to provide a uniform water supply to your plants. Water your garden in the morning so the foliage is dry before the sun goes down. Make sure you water the broccoli enough to moisten the soil to a depth of at least 6 inches. If you only sprinkle the plants lightly, your broccoli will have shallow roots and not get the nutrients it needs to provide you with a good crop. Try not to get developing heads wet when watering.
Control weeds by mulching. Digging around the plants can harm the roots. You can also prevent weeds with Corn Gluten Meal organic pre-emergent herbicide. (Note: Do not use Corn Gluten Meal if you are starting plants from seed.)
Mulching also helps to keep soil temperatures down.
Fertilize regularly beginning about three weeks after transplanting.
Pests and Diseases
Common pests include aphids and cabbage loopers. If you notice curling leaves, it may mean that the plant’s sap is being sucked by insects.
Cabbage loopers and other worm pests usually leave small holes on the leaves. Look for the eggs on the under side of the leaves. You can control with either Bacillus thuringiensis (Bt) or Spinosad.
Bt is a highly selective bacterium that only affects caterpillars and worms, which means it will not harm other insects or wildlife. Bt is organic and safe to use up to the day of harvest. Spinosad is another safe organic insecticide that keeps working longer than Bt and kills a broader range of insects, including caterpillars, thrips, and beetles. Instead of Bt’s one or two days’ residual effect, Spinosad keeps killing for up to four weeks.
For those looking for a more general organic insecticide, we recommend Neem Oil or Triple Action (a combination of Neem and Pyrethrin).
One type of disease that can attack your broccoli is Clubroot. Clubroot is a soil fungus that can quickly cause plants to wilt. Gently dig up the roots and inspect them to see if they are gnarled or misshapen. If so, the entire plant, including all roots and root tendrils, must be removed. Act quickly to remove the plants so that the fungus doesn’t continue to live in the soil. You may be able to rectify the problem by raising the pH of your soil to above 7.2.
Downy mildew is another fungus that causes yellow patches on leaves, and is usually caused by moist weather. Keep leaves as dry as possible with good air circulation and avoid over watering.
You can help prevent many pests and diseases by practicing regular crop rotation where possible.
Note: Never compost diseased plants.
Broccoli is usually ready to pick 65 to 70 days after planting, depending on the variety and weather conditions. Watch for the main head to get to about 3 inches in diameter. The buds of the head should still be firm and tight without any flowering. Once the plant has bolted (is flowering), it’s too late to pick. The vegetable will become bitter to the taste.
For best taste, harvest in the morning before the soil heats up.
To harvest, just cut the main stem of the broccoli about 5 to 8 inches below the head. Cut the stalk at an angle. This will encourage side heads to form after the main head is harvested.
Store broccoli in the refrigerator for up to 5 days. If you wash before storing, make sure to dry it thoroughly. Broccoli can be blanched and frozen for up to one year.
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