Have you had it with bitter broccoli? If so, you are probably wondering why it happens, and how you can avoid it.
So, why is your broccoli so bitter? Broccoli becomes bitter when the plant starts to “bolt”, or produce flowers. Broccoli will bolt due to age or environmental conditions. Certain varieties of broccoli are also more bitter than others.
Of course, there are lots of different environmental conditions that cause broccoli to bolt and become bitter.
In this article, we’ll look at some of those causes and how to prevent bitter broccoli.
Let’s get going.
Why is My Broccoli Bitter?
Broccoli develops a bitter flavor when the plant starts to produce flowers, also called bolting. It is a natural part of a broccoli plant’s reproductive cycle.
Often, broccoli will begin to bolt and produce flowers when the soil temperature reaches 80 degrees Fahrenheit (27 degrees Celsius). Sometimes, bolting can happen before the broccoli forms a full-sized head.
Why is My Broccoli Bolting?
Broccoli bolts in order to produce flowers and seeds to create the next generation of plants. Bolting can happen for several reasons, including:
- Age (the plant has grown to mature size and is ready to reproduce)
- Heat (the plant will flower early if it gets too hot)
- Water Stress (under watering, especially during dry times)
- Poor Nutrition (for example, low nitrogen levels)
- Late Transplant (the plant was left indoors too long when grown from seed)
Let’s take a closer look at the reasons why broccoli bolts, starting with age.
One simple but overlooked reason for bitter broccoli is age. When a broccoli plant reaches a certain age, it is mature and ready to reproduce.
At that point, it will produce flowers and seeds in an attempt to reproduce. Usually, this occurs after:
- 65 to 90 days if you grow broccoli from seed (direct sowing in the garden)
- 50 to 75 days if you transplant seedlings (starting seeds indoors)
When broccoli plants are mature, the central head will be up to 8 inches (20 centimeters) in diameter. However, most mature heads are 4 to 6 inches (10 to 15 centimeters) in diameter.
When your head of broccoli gets close to this size, it is time to start thinking about harvest. It is best to harvest broccoli when the little green buds (florets) on the heads are still packed close together.
“Harvest broccoli when heads reach a usable size, while they are still tight and before flower buds have opened.”https://extension.umn.edu/vegetables/growing-broccoli#harvest-451964
The color of the head should be deep green. If the heads are not tight and have begun to spread out or turn yellow, then the broccoli is bolting, and it will become bitter.
In a hot climate, you may have trouble getting broccoli to mature fully before the heat causes it to bolt. In that case, you might consider some faster-maturing broccoli varieties, such as:
- BC1611 – this hybrid broccoli variety yields multiple small heads, instead of one large central head. The stems stay small, so they are more tender and edible. At only 33 days to maturity, you will be ready to harvest in less than 5 weeks! You can find BC1611 Broccoli at Johnny’s Selected Seeds.
- Burgundy – this hybrid broccoli variety also yields multiple smaller heads with a stunning purple color. They only take 37 days to maturity, so you will be harvesting them in no time! You can find Burgundy Broccoli at Johnny’s Selected Seeds.
- Spring Raab – this open pollinated broccoli variety yields small heads on thin stems. They only take 42 days to mature, so you will be harvesting in only 6 weeks. You can find Spring Raab Broccoli at Johnny’s Selected Seeds.
You could also opt for heat-tolerant broccoli varieties, such as:
- Green Magic – this hybrid broccoli variety yields one large main head and then smaller side shoots if harvested in time. They take 57 days to mature, but they are heat tolerant, and the larger heads make it worth the wait. You can find Green Magic Broccoli at Johnny’s Selected Seeds.
- Gypsy – this hybrid broccoli variety yields one large main head followed by smaller side shoots. They take 58 days to mature, and have some heat tolerance as well. You can find Gypsy Broccoli at Johnny’s Selected Seeds.
Of course, if you want to grow broccoli without worrying about bolting and bitterness, then avoiding heat as they grow is the best way to do it.
Broccoli is a member of the brassica family (cruciferous vegetables). The brassica family also includes cabbage and cauliflower.
Broccoli and other brassicas are cool weather crops. Broccoli prefers to grow in cool soil, and can germinate in soil as cold as 40 degrees Fahrenheit (4 degrees Celsius).
The Old Farmer’s Almanac suggests starting broccoli seeds indoors 6 to 8 weeks before the last spring frost date. Then, transplant them outside 2 weeks before the last spring frost date.
If you plant seeds directly outside, you can do so 2 weeks before the last spring frost date. You can find frost dates for your area using this tool from the Old Farmer’s Almanac.
In general, you should not plant broccoli if temperatures are over 90 degrees Fahrenheit (32 degrees Celsius). In fact, according to Texas A&M University:
“High temperatures at heading time usually causes premature flowering and consequently reduces the quantity of home-grown broccoli. Broccoli will flower quickly if it is forced to mature at temperatures much above 80 degrees F.”https://aggie-horticulture.tamu.edu/archives/parsons/vegetables/broccoli.html
When soil and air temperatures get too hot, broccoli will start to bolt and flower prematurely. This will cause a bitter flavor in the heads.
Even if the heads are small, you should harvest them if they show signs of early bolting. That way, you still get something from the plant.
Also, for varieties with a main head, you might still be able to harvest side shoots (ideal for stir-fries!) if the weather cools down a bit.
A lack of water during drought conditions will also lead to early flowering and bitterness in broccoli. High temperatures, strong sunlight, and dry air can all contribute to this problem.
When broccoli does not get enough water, it may flower early. This is because it wants to try to reproduce before it gets to the point where it cannot survive.
To avoid water stress, check your broccoli plants daily and water if the soil feels dry at a depth of 2 inches (5 centimeters) or deeper.
If you have sandy soil, you can add compost or manure to make it retain more water for a longer time. The extra organic material will also attract earthworms and beneficial bacteria to your garden.
A layer of mulch over your soil will also prevent evaporation due to heat and sunlight. You can learn more about how to treat dry soil in my article here.
A broccoli plant that is subjected to poor nutrition will also experience stress. This stress will make the head taste bitter.
“Other causes of early flowering include nitrogen stress (too little).”https://extension2.missouri.edu/g6400
You can often cure a lack of nitrogen in soil by adding some aged manure or a high-nitrogen fertilizer.
However, remember that a nutrient deficiency in plants may not always be caused by a lack of nutrients in the soil. A soil pH imbalance or a lack of water can also lead to nutrient deficiencies in plants.
Broccoli prefers soil with a pH in the range of 6.0 to 6.8 (slightly acidic). If your soil is too acidic, you can add lime (calcium carbonate) to increase the pH.
Just be sure to do a soil test before adding anything to your soil. That way, you can make sure that the pH is really off before trying to solve a problem you might not even have!
It is probably best to transplant broccoli into the garden, rather than direct sowing. However, you don’t want to wait too long to transplant!
https://extension2.missouri.edu/g6400According to the University of Missouri Extension:
“Broccoli that is planted too late in the spring will experience heat stress and flower early. Transplanting an oversized transplant will often result in premature flowering.”https://extension2.missouri.edu/g6400
So, be sure to keep track of the age of your broccoli plant, based on when you planted the seed. Remember to transplant broccoli outdoors at the right time (about 2 weeks before the last frost date).
How Do You Get the Bitterness Out of Broccoli?
If you have bitter broccoli that has already been harvested, the remedies above won’t help you. So, how do you get the bitterness out of broccoli that has already been harvested?
Well, one thing you can do is to cook and season it properly.
When cooking bitter broccoli, try boiling rather than steaming. When you boil broccoli, the water you drain out will remove some of the bitter compounds (baking or steaming will not do this).
After cooking, season the broccoli with flavors such as salt, spices, or citrus (lemon, orange, or lime.).
Another option is to cut up the broccoli and use it as part of a stir-fry. If you put it in a stir-fry with pineapple chunks, the sweetness of the pineapple juice will offset the bitterness in the broccoli.
Finally, remember that some people’s taste buds are more sensitive than others. There is nothing you can really do about this, so if you taste bitterness in broccoli more than other people, chalk it up to genetics.
Now you know why your broccoli tastes bitter. You also know how you can prevent it from happening in the future so that you can enjoy your harvest.
If you find broccoli heads turning brown, it could be due to lack of water, or another reason – you can learn more in my article here.
You might also want to read my article on fall planting for cool weather crops.
I hope you found this article helpful. If so, please share it with someone who can use the information.