WHEN TO PLANT BRUSSEL SPROUTS – PLANTING GUIDE 2021

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when to plant brussel sprouts

Packed with vitamins and antioxidants, brussel (or rather, Brussels) sprouts are not the easiest vegetable to grow.

Our 2021 planting guide will help simplify the planting and growing process for you. Your reward will be harvesting the fruits of your labor and putting freshly homegrown Brussels sprouts on your table.

When to plant Brussel sprouts? The best time to plant Brussels sprouts depends on where you are and whether you are growing them from seed or seedlings. Because they thrive in cooler weather, it’s generally best to plant Brussels sprouts seeds in early to mid-summer summer for a fall harvest. If you plant Brussels in spring, the plants are likely to bolt before forming sprouts. 

Another important factor is that they prefer cool, moist growing conditions. They also grow very slowly. So we’re going to start by discussing the impact of different climates on when to plant Brussels sprouts. 

PLANTING BRUSSEL SPROUTS IN DIFFERENT CLIMATES

planting brussel sprouts

Named after the Belgian city of Brussels, Brussels sprouts are incorrectly named brussel sprouts by most people. Their name should give a clue to the kind of climate they thrive in. 

Belgium has a temperate climate with four very distinct seasons. Unlike many other European countries that fluctuate between scorching hot and freezing cold weather, Belgium experiences mild, cool winters and summers that are slightly warm. 

According to Brussels Info that supplies information for tourists and travelers, the average low in winter is 34°F/1°C and 73°F/23°C in summer. This tallies with the ideal temperatures for growing Brussels sprouts.

A good rule of thumb is that Brussels sprout plants prefer temperatures of between 45°F/7°C and 75°F/24°C. They don’t do well in warm weather, and it’s well-known that their flavor improves if they are subjected to a bit of light frost. 

So, Brussels has the ideal climate for Brussels sprouts! 

TROPICAL CLIMATE

One of five basic climate types, a tropical climate is hot and humid. There is more than 59 inches of rain every year and average temperatures are more than 64°F/18°C throughout the year. 

Clearly, a tropical climate is less than ideal to grow Brussels sprouts. It’s too hot and too wet. 

DRY CLIMATE 

Dry climate zones are, literally, dry. This is because there is very little rain, and what moisture there is in the air evaporates very quickly. 

Since Brussels sprouts requires moisture, you’ll need to keep them watered. You will also need to be sure that the temperature isn’t too hot. 

In arid and semi-arid areas, temperatures can get as high as 110-120°F/43.5-49°C and often drop below freezing in winter.

While Brussels sprouts like cool weather, they become puffy and soft if the temperature is above 80°F/26.6°C. They are also more prone to aphid attack while the sprouts develop in hot weather.  

The best solution for a dry climate is to grow your Brussels in a greenhouse. That way you can control climatic conditions. 

TEMPERATE CLIMATE

This is an ideal climate for growing Brussels sprouts. Generally, you will sow seeds in the fall, four to six weeks before the first frost, depending on the variety. Then the sprouts develop and grow during the cooler months. 

Seedlings should be transplanted in full sun just before the last frost. 

CONTINENTAL CLIMATE

Regions with a continental climate have warm to cool summers and winters are very cold. The temperature in winter often falls below -22°F/-30°C and strong winds and snowstorms are commonplace.

According to the  Cornell Cooperative Extension Vegetable Program, Brussels sprouts are well suited to the New York climate, which is, of course, generally humid continental. Farms in the state that produce Brussels, sow the seeds in beds or a greenhouse five to six weeks before they transplant in mid-June. 

Typically, they harvest the sprouts between September and November. 

POLAR CLIMATE

It’s not rocket science to realize that it’s extremely cold in polar climate zones. Even in summer, the temperature doesn’t go any higher than 50°F/10°C. 

While they will generally be grown in greenhouses, the Alaska Railroad Record (1916), states categorically that Brussels sprouts and other hardier vegetables can be grown throughout most of Alaska south of the Arctic Circle. 

The proviso is that garden sites are sheltered and get sunshine. 

CHOOSING BRUSSEL SPROUT SEEDS 

brussel sprout seeds

There is a huge selection of hybrid, heirloom, and certified open-pollinated and non-GMO organic Brussels sprouts seeds. There are also late-season, early-maturing, and even ornamental types. 

What’s exciting, too, is that even though pale green is the common color for Brussels sprouts, different sprout plants produce Brussels of different sizes and colors.

These range from dark emerald green to a reddish-purple hue and they all look a bit like miniature cabbages – not surprising since they’re from the same family. 

Most Brussels are between 0.6 and 1.6 inches/1.5-4 cm in diameter, but you will find some varieties that produce tiny, button-like buds that are under an inch in diameter. Some loose-leafed varieties are as big as two inches in diameter. 

The one thing they all have in common is that they are a cool weather plant that grows best in temperature between 58°F/14.5°C and 60°F/15.5°C

WHERE TO BUY BRUSSELS SPROUT SEEDS

From the plant species, Brassica oleracea, seeds are available online and from local garden centers and other plant and seed stockists. Most seed packets will say where and in what conditions the various types grow best. Growing information is also commonly printed on packets. 

Popular hybrid seeds include Green Gems and Long Island Improved, while Catskill is an heirloom seed that usually produces huge yields. 

According to Brussels sprouts fact sheet written by extension horticulturist Alvin R. Hamson, and published by the Utah State University in 1989, almost all the hybrids grown in the U.S. come from two main, well-established types:

  1. Jade Cross hybrids
  2. Prince Marvel or Captain Marvel hybrids

You can also harvest your own seed. 

HARVESTING YOUR OWN BRUSSELS SEEDS

Brussels sprouts are a biennial vegetable, which means that they have a natural growth cycle that lasts for two years. They will flower again, and produce seeds, in their second growing season, after cool weather. 

The seeds form in pods, and you will need to harvest the pods and then let them dry out for a few weeks. It can take quite a lot of force to break the pods open. Don’t leave them to dry out on the plant because mature pods tend to shatter and birds love the seeds. 

When the pods are dry, put them into a cloth bag and hit the bag against a solid surface to break the pods open. Alternatively, you can jump on the bag to break the pods. Then gather the seeds and store them in a dark, cool, dry place in an airtight container. 

HOW TO PLANT BRUSSEL SPROUT SEEDS

Whether you are going to plant your seeds inside or outside, you first need to decide when to plant them. You will need to work backward based on the assumption that the seeds will take four to five weeks to grow large enough to be transplanted successfully. 

Wherever you decide to grow Brussels sprouts, remember that they prefer fertile soil but will grow in lighter, sandy soil. It must be well-drained and should have a pH of 6.5-7.5. Adding organic matter to the soil will help to keep it moist while the Brussels sprouts develop and grow. 

If your Brussels are going to be started indoors, plant them in seed trays about ½ inch deep. If you are going to plant Brussels outdoors, follow the same ½ inch-deep rule and position them two to three inches apart. Mulch the soil to keep it moist, water often, and fertilize about three weeks before you are planning to transplant the seedlings. 

Don’t be surprised to find that some seeds grow stronger plants than others. It’s generally best to thin them out when they are about two inches tall, keeping the strong plants and removing the ones that aren’t doing too well. 

HOW TO WATER BRUSSEL SPROUT PLANTS

Brussels sprouts grow best if they get about 1-1.5 inches of water every week. This is especially important during the heat of summer in warm-climate areas. 

Many people with small home vegetable gardens water by hand when they grow Brussels sprouts. But an easier way to water is with hand-move sprinkler lines that can be used for other vegetable plants as well.

Brussels that are grown commercially are commonly watered using furrow or trickle irrigation methods. This is because commercial growers generally incorporate fertilizers and herbicides into their irrigation systems. 

HOW TO GROW BRUSSEL SPROUTS

Even though not everyone likes Brussels sprouts, they are the acknowledged aristocrat of the cabbage family. Properly grown, correctly harvested, and carefully cooked, they are a gourmet item with a delicate, slightly sweet, nutty flavor. 

They generally taste best if they have matured in cool conditions and are harvested when they’re ¾ to 1 inch in diameter. If picked past their prime, Brussels will often have a bitter taste. If overcooked, they will become mushy and will smell and taste yucky. 

So, how do you grow them correctly?

TRANSPLANTING BRUSSELS SEEDLINGS

Whether you have grown your own seedlings or have bought established seedlings from a garden center, when they are about 5-7 inches tall, space or plant them about 1-2 feet apart in rows that are about three feet apart. Transplant them a little deeper than before, so that the lowest leaves are a little above the soil level. Water them well. 

PESTS & DISEASES TO WATCH OUT FOR

Like cabbage and broccoli, Brussels sprouts maturing are prone to some common diseases and pests. Common pests include infamous cabbage loopers, which are moths that chew holes in the leaves of brassica plants. Cabbage worms, aphids, Harlequin bugs, and cabbage root maggots can also cause problems. 

Common diseases that infect Brussels include black rot, blackleg, and clubroot, which can be managed by raising the pH of the soil to about 7.0. The other diseases can be minimized by rotating your crops every year. 

HOW LONG DO BRUSSEL SPROUTS TAKE TO GROW?

As we’ve said, Brussels sprouts develop very slowly. Most growers say it takes between 80 and 100 or 130 days for the plants to reach maturity and produce a decent crop. But according to the Cornell Veggie program, it can take up to 180 days depending on weather conditions and the variety you are growing. 

For example:

  • Catskill 90-110 days
  • Green Gems 85-95 days
  • Jade Cross 85-100 days
  • Long Island Improved 80-115 days
  • Prince Marvel 110-120 days

Because they are a biennial vegetable, you will get a second crop after a year. 

CONCLUSION

Brussels sprouts are not very easy to grow. They are cool-weather plants and they take a long time to develop and mature. But, if you enjoy Brussels, and you live in a temperate or continental zone, growing them is a challenge worth pursuing. 

We have provided you with loads of tips and advice in our latest planting guide. This includes choosing the most suitable seeds, planting seeds and seedlings, and watering the plants.

We have also included a section on how to harvest your own Brussels seeds so you can start your own heirloom variety if you want to!

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