By: Susan Patterson, Master Gardener
If you’ve noticed any unusual looking fruit or vegetable crops in the garden, then it is highly likely you are experiencing cole crop buttons or buttoning of stone fruits. This is especially true if you have had unseasonable weather or insect issues. So what is buttoning and what causes it? Continue reading to learn more about this phenomenon and how to fix plant buttoning in the garden.
Buttoning is the result of stress, brought about by unfavorable weather or other reasons in both cole crop vegetables and stone fruit trees. Buttoning produces misshapen vegetables and fruits as well as stunted growth.
Kale, Brussels sprouts, cauliflower, broccoli, and cabbage are cool-season vegetables known as cole crops. The word cole refers to stem and is not relative to the fact that these particular vegetables are tolerant of cold weather.
Cole crop buttons are small heads that appear on plants that suffer from insect damage, drought, excessive salt, nitrogen shortage, or severe weed competition. Buttons can develop on broccoli and cauliflower when they are exposed to very low temperatures. Cabbage is not so picky.
Proper planting and care will help protect your plants from buttoning. Knowing how to fix plant buttoning by being prepared and carefully timing your plantings may save your crop. Top covering plants, if necessary, and providing a regular water and feeding schedule is also helpful.
Stone fruits, such as peaches, nectarines, apricots, cherries, and plums, need a certain number of cold days known as chilling units (CU) to produce fruit properly. When a stone fruit tree does not get enough chilling time, the bloom is late and lasts longer than normal. There are other abnormalities in the pistil as well, with both pollen development and fruit set reduced.
Buttons form in some varieties because of flowers that have set but never truly develop into viable fruit. The fruit ripens but is small and malformed or conjoined. Unfortunately, buttoning cannot be seen early in the season, so growers are unable to thin out the abnormal fruit.
Buttons attract insects and promote disease over the winter months, so removal is the best option. Unfortunately, there is little you can do to prevent the buttoning of stone fruits since it is more of a weather issue than anything else. When planting a stone fruit tree, make sure that the variety you choose will be able to get the proper amount of chilling during the winter months in your area.
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Read more about Environmental Problems
» Proper head formation in cauliflower is very sensitive to environmental conditions.
» Warm temperatures and dry conditions can result in problems with head size and curd quality.
» Synchronizing varieties, planting dates, and anticipated weather conditions can help minimize problems with head development and curd quality.
Compared to broccoli and cabbage, cauliflower is very sensitive to environmental conditions. In particular, proper head formation and curd quality require a fairly narrow range of temperature and moisture conditions. It is not unusual for heads to fail to form properly and for problems with curd quality to occur. 1,2,3 Cool temperatures and a moist atmosphere are most favorable for cauliflower production. Curd (head) development is triggered by a combination of plant age and air temperature factors. The optimal range of temperature for the initiation of heads in main season cauliflower varieties grown in North America is 50° to 60°F. However, there are tropical and winter varieties that form heads at higher and lower temperatures respectively. Cultivars and planting dates must be coordinated so that heading occurs when temperatures are in the correct range. 1 Head quality can also be affected by exposure to sunlight. Curds may turn yellow if exposed to the sun, and the developing heads must be covered to prevent discoloration. 1
Figure 1. The condition of riciness of a head of cauliflower. International Produce Training, http://www.ipt.us.com.
Both riciness (riceyness) and fuzziness of cauliflower heads can occur when temperatures are warm (above 80°F) during head formation. 1,2 High humidity and nitrogen levels can also contribute to the development of these conditions. 4 Riciness is a condition where the floral parts elongate and grow up through the heads and small, white or purple flower buds form. 6,7 The buds separate giving the curd an open and uneven appearance (Figure 1). Fuzziness is similar, with the heads developing a fuzzy/velvety appearance because the flower pedicels elongate (Figure 2). Fuzziness is caused by large day/night temperature fluctuations (high day temperatures and low night temperatures). Some varieties are more susceptible than others to these problems. Planting varieties at the correct time to avoid warm weather during head formation is the best way to manage both of these conditions. 6,7
Figure 2. Fuzziness of cauliflower is caused by elongated pedicels. International Produce Training, http://www.ipt.us.com.
Buttoning is the term used to describe the condition of a plant forming small curds that never reach a marketable size. Buttoning is usually the result of curds developing on small plants where there is not enough leaf area to support curd growth. Conditions that can lead to buttoning include cold temperatures at planting, temperatures over 80°F at the time of planting, low soil fertility (nitrogen), micronutrient deficiencies, low soil moisture, and damage from disease or insects. 3,4 One of the most common causes of buttoning is using seedlings that are too old at the time of transplanting. Buttoning is also more likely to occur with early season varieties.
Some references refer to buttoning as premature curd formation, indicating that curd initiation starts before the plant can support curd development. These articles speculate that seedlings which have initiated curd formation (seedlings that are “past their juvenile state”) before transplanting are more likely to develop problems with buttoning. However, a study published in 1984 found that the frequency of buttoning was associated with restrictions of leaf growth, but not with the amount of curd initiation at the time of transplanting. 5
Plants that were older and larger at the time of transplanting tended to have reduced leaf growth after transplanting, and this reduced leaf growth was the main cause of buttoning. In this study, seedlings that had more than 14 leaves and had dry weights greater than 1.1g at transplanting were “prone to severe buttoning.” This research suggests that any conditions that retard leaf growth after transplanting can result in a higher frequency of buttoning. If planting is delayed and seedlings are getting too large, storing the seedlings at low temperatures may help retard seedling growth until they can be transplanted, reducing the likelihood of buttoning. These researchers also explain that later season varieties tend to produce more leaves before curd initiation and can sutain more leaf area reduction without suffering from buttoning as compared to earlier varieties that produce fewer leaves.
Blind bud is a condition where no central growing point forms and no head develops on a cauliflower plant. This condition is usually associated with periods of extremely warm weather, with day-time air temperatures over 86°F and night-time air temperatures over 77°F. 1,4,5 Other factors that can cause a lack of head formation include mechanical injury, insect damage, and bird feeding. Some varieties tend to be more susceptible to this condition than other varieties. 1
Figure 3. Loose and leafy curds of cauliflower.
When bracts (small green leaves) grow between the curd segments in a head of cauliflower, the heads are said to be suffering from leafy curds. 2,4 This condition is usually associated with high temperatures and low soil moisture levels (drought) at the time of head formation. 3,4
Stressful conditions, such as fluctuating temperatures and moisture levels, that slow plant growth can result in the formation of heads with loosely formed, less compact curds, a condition known as loose curds (Figure 3). Rapid vegetative growth resulting from excessive nitrogen levels can also result in the formation of loose curds. 2,4
The curd of some varieties will yellow if exposed to the sun, and these varieties require a period of blanching, where outer leaves are gathered and tied around the developing head for a period of time to prevent discoloration. Yellowing is more likely to occur when temperatures are above 80°F. 1 The blanching procedure involves gathering the large leaves and bringing them together over the heads and binding the leaf tips together with a rubber band or twine. This is done when the heads are two to three inches in diameter. 3,8 Blanching should be done for four to eight days during warm weather and for as long as 15 days when conditions are cooler. Some cauliflower varieties are self-shading, with leaves that grow up over the heads, and do not need to have leaves tied together. 8 Other varieties, including the green and orange colored varieties, are not greatly affected by sun exposure. 4 A browning of the curds can develop as a result of boron deficiency. 4
Symptoms of hollow stem start as small cracks in the internal stem tissue. As the stems grow, the cracks expand and cavities form. These cavities may extend up into the head. Hollow stem is associated with conditions that encourage rapid plant growth including wide plant spacings and high nitrogen levels. 4 Varieties vary in their susceptibility to hollow stem. 7 Boron deficiency can also cause the formation of hollow stems with internal browning (Figure 4). 2 Growing varieties at the appropriate plant spacings and providing balanced and appropriate fertilization will usually prevent the formation of hollow stems. 6
Figure 4. Hollow stem and internal discoloration caused by boron deficiency. John Howell, University of Massachusetts.
1 Koike, S., Cahn, M., Cantwell, M., Fennimore, S., Lestrange, M., Natwick, E., Smith, R., and Takele, E. 2009. Cauliflower production in California. UC Vegetable Research and Information Center. Publication 7219.
2 Sanders, D. 2001. Cauliflower. NC State Extension: Horticulture Information Leaflets.
3 Cabbage, broccoli, cauliflower, and other brassica crops. 2018. New England Vegetable Management Guide. https://nevegetable.org/crops/cabbage-broccoli-cauliflower-and-otherbrassica-crops.
4 Johnson, G. 2008. Disorders in cole crops. University of Delaware, Cooperative Extension. https://extension.udel.edu/weeklycropupdate/?p=464.
5 Wurr, D. and Fellows, J. 1984. Cauliflower buttoning-the role of transplant size. Journal of Horticultural Science 59:419-429.
6 University of California. 1987. Integrated pest management for cole crops and lettuce. UCANR Publication 3307.
7 Dickson, M. 2007. Riciness of cauliflower. In Compendium of Brassica Diseases, Rimmer, S., Shattuck, V., and Buchwaldt, L. editors. The American Phytopathological Society, St. Paul.
8 Trounfeld, J. 2010. Cauliflower. University of Maryland Extension. GE 107. Websites verified 10/25/2018
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Growing large heads of cabbage is a great way to create a beautiful garden. This cool season vegetable belong to a group of plants also known as cole crops. Cole crops are simply crops that belong to the mustard family (Brassica). Other cole crops include Broccoli, Brussels Sprouts, Cauliflower, Collards, Kale, Kohlrabi, Mustard, Turnips and Watercress.
Different cole crops need to be planted at different times. One thing they share in common is that they are best harvested before the heat of summer arrives. In cooler parts of the United States these crops need full sun but in the south where cool seasons are short, they can handle a partially shaded garden to help reduce extreme heat. Knowing your first and last frost date will help you get your crops in the ground at the proper time.
Cole crops can tolerate cooler temperatures far better than other crops and therefore we find ourselves planting them a good 4 to 6 weeks before our tomatoes and peppers. They often have a longer harvest date than warm season vegetables therefore getting a jump on the hot weather is crucial. Amending our garden with the proper amendments will assure that our plants produce to the best of their abilities also.
Cabbage like all cole crops, requires consistent watering as well as consistent nutrition. You can plant cabbage in the late winter or 4 weeks before your last spring frost date . For fall plantings, you will want to plant your young plants in the ground 6 to 8 weeks before your first fall frost date . Cabbage plants maturing in cooler weather produces a sweeter cabbage.
All cole crops prefer a soil pH in the range of 6.5 to 6.8 so incorporating lime to the soil may be necessary. Cabbage requires at least 6 to 7 hours or more of sun each day. Incorporate rich organic compost to the soil as well as applying a slow released vegetable fertilizer with micronutrients . Plant your cabbage plants where the stem is 1 or 2 inches deeper in the soil to give them good footing.
Most cabbage requires spacing of 12 to 24 inches. Larger head varieties can require 36 inches of spacing. Cabbage requires consistent watering and soaker hoses are great for watering below the plant. Cabbage requires 1 to 1.5 inches of water each week.
Plant your broccoli 2 to 3 weeks before your last spring frost date and about 90 to 100 days before your first fall frost date . Broccoli requires the same care as cabbage but spacing should be 18 to 24 inches. Soil pH ranges from 6 to 7, therefore lime may be necessary. Incorporate rich organic compost to the soil as well as applying a slow released vegetable fertilizer with micronutrients .
Mulching the soil helps hold in moisture for the plants as well as cooling down the soil. Be sure your plants receive 1 to 1.5 inches of water per week. Read our post on how to harvest broccoli .
Your Broccoli will need harvesting about 90 days after planting your plants. Warm summer temperatures will force them to bloom so be sure to harvest them as the buds swell but before they bloom, otherwise it will taste bitter. Fall harvests often taste better than spring harvests. In the wild, your broccoli will be smaller than that found in the grocery store, so don't wait for it to get bigger.
Plant cauliflower the same time as cabbage and after temperatures are below 75 degrees. Cauliflower demands cool temperatures but not freezing temperatures. Space your plants 18 inches apart. Cauliflower requires a pH of 6.2 to 6.8. Incorporate rich organic compost to the soil as well as applying a slow released vegetable fertilizer with micronutrients .
It may be a little more difficult to have success with, as they require shading when temperatures heat up. Temperatures that are too hot or cold will force a plant into "buttoning". This is when a plant prematurely makes button size heads. Inconsistent watering can also trigger buttoning. Mulching the soil helps hold in moisture for the plants as well as cooling down the soil. Be sure your plants receive 1 to 1.5 inches of water per week.
Because cauliflower likes it not too hot and not too cold, there are few climates perfect for growing. This is why about 75% of the cauliflower in the United States is grown in the valley regions of California.
Start seeds indoors 6 to 8 weeks before your last spring frost date . Transplant 2 weeks before last spring frost date. for a fall harvest, plant your Brussels sprouts in the mid to late summer. Like the other cole crops, brussels sprouts require 6 hours of sun or more. 6.2 to 6.8 is a good soil pH range.
Incorporate rich organic compost to the soil as well as applying a slow released vegetable fertilizer with micronutrients . Space your plants 18 to 24 inches apart. Mulching the soil helps hold in moisture for the plants as well as cooling down the soil. Be sure your plants receive 1 to 1.5 inches of water per week.
Boron is a micronutrient needed in higher demand than other vegetables to keep plants healthy and to prevent plant from developing hollow stems. Borax laundry detergent can provide your plants with this boron if you find your plants have developed hollow stems then use 1 level tablespoon per 5 quarts of water over 50 square foot. MORE IS NOT BETTER!
Brussels sprouts are ready to harvest once the heads are 1 to 2 inches in diameter and the heads are firm and green. Twisting the heads will make them pop right off. Sprouts will continue through cold weather but stop producing after the first hard frost.
Collards are a great southern favorite and loaded with vitamins C,E and A and minerals like Calcium, Magnesium and Iron. Collards resemble a sweet cabbage in taste and taste best when leaves are young and when harvested in the cold weather. Collards grow best in full sun but in southern hot climates your spring planting will appreciate some late afternoon shade.
Plant your spring plants 3 to 4 weeks before the last spring frost date . Summer plantings should be planted 6 to 8 weeks before your first fall frost date for your fall/winter harvest. Harvest leaves once they grow to 10 inches. Younger leaves are less tough and not as stringy. Pick lower leaves first, working your way inside.
Like the other cole crops, collards prefer consistent moisture throughout the growing season. 6.5 to 6.8 is a good soil pH range. Incorporate rich organic compost to the soil as well as applying a slow released vegetable fertilizer with micronutrients . Space your plants 18 to 24 inches apart. Mulching the soil helps hold in moisture for the plants as well as cooling down the soil.
Mature collard leaves can tolerate colder temperatures than most other crops. You can continue to harvest your plants until temperatures reach the teens. Protect young spring plants from a late spring freeze, as young tender plants do not handle frost.
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Cauliflower (Brassica oleracea, Botrytis group) is also called "heading broccoli". It is a type of cabbage that originated in southern Europe. For many gardeners, cauliflower is one of the most temperamental crops to grow in the vegetable garden. Unlike broccoli which produces side shoots for additional harvests, there is only one opportunity for a good crop with cauliflower because the plant produces only one head. The head, sometimes referred to as a "curd", is formed from shortened flower parts at the top of the plant.
There are several reasons why cauliflower can be tricky to grow in a home garden - most of them due to environmental factors. Too much heat prevents the cauliflower head from forming. Cauliflower must be grown at a continuous, steady rate through it entire life, from seedling to harvest. Anything which slows or stops its growth, such as insects, lack of water, or excessive heat or cold, may prevent development of the head.
Some plants may produce heads prematurely on relatively small plants. This occurrence, called "buttoning", is frustrating to gardeners. It is caused by any type of stress that interrupts the plants growth. It often occurs when large transplants, or those crowded in cell packs and flats, are planted into the garden. Setting cauliflower plants outdoors when temperatures are still cold may also be a problem. To avoid "buttoning", plant small, healthy transplants two weeks before the average last frost date in your area. In young cauliflower plants, there is a fine balance between vegetative and reproductive growth. Any stress tips the balance toward button formation.
Success with growing cauliflower begins with selecting a variety that performs well in Iowa. Varieties that require a growing season of 50 days or more are recommended. Early maturing varieties are more susceptible to buttoning than later varieties. 'Snowcrown' hybrid, which matures in 60 days, is an excellent variety for home gardens.
Cauliflower is usually set out as transplants that were started indoors 6 to 8 weeks before planting. Cauliflower transplants are easy to grow. Sow the seed 1/4 inch deep in individual containers, such as peat pots, or in furrows in flats and later transplant the seedlings to individual containers or cell packs containing fresh, well drained potting soil. The optimum soil temperature for seed germination is 80 F., however, cauliflower will germinate at temperatures as low as 50 F. After germination, set the seedlings in a location that receives direct sun or grow them under artificial lights. The growing temperature show be approximately 60oF. Keep the soil moderately moist, but not soggy.
Harden-off the transplants before planting them in the garden. About 5 days to a week before planting, set them outside in the shade and gradually expose them to longer periods of sun. Plant the young transplants in the garden on a cool, cloudy day or late in the afternoon. It is a good idea to apply a starter fertilizer at planting time. Plant cauliflower two feet apart in rows 30 to 36 inches apart.
Cauliflower grows best during sunny days with air temperatures of 70 F. If temperatures are above 80 F. during curd formation, leaves may form in the head, it may become rough in texture, or have a purple or green coloration.
When the head is golf to tennis ball size (2 to 3 inches in diameter), it needs to be protected from sunlight. This keeps the head white, protecting it from sunscald and turning yellow and off-flavored. Tie the outside leaves loosely over the head with a strip of old nylon stocking or soft cloth. Some gardens use spring-type clothespins to tie the cauliflower leaves up.
The heads will be ready for harvest one to two weeks after covering, depending on the weather. Check the head every few days so that it does not become overmature. Harvest cauliflower heads when they are six or more inches in diameter but before the flower parts separate.
For fall plantings, transplants are started in early July and set out in the garden in early August. Mulch around the young plants and keep them well-watered.
This article originally appeared in the February 28, 1997 issue, p. 16.
Sometimes during the reproductive stage, developing heads begin to discolor, a phenomenon called browning.
Florets have a brown, red, or yellow hue, either all over, or in patches.
Generally, browning is caused by a lack of boron, a micronutrient that is essential to healthy cell development. A deficiency may cause a progression of issues beginning with saturated stems and florets, followed by discoloration, deformation, and bitter flavor.
However, there are other reasons why a head that’s well underway may suddenly begin to change color.
It may be caused by too much direct sunlight. There are varieties that “self-blanch,” keeping their heads creamy white by covering them naturally with curved leaves. Other types do not, leaving them vulnerable to UV rays.
It’s also possible that boring insects such as aphids are leaving trails of “honeydew” that invite diseases such as downy mildew that cause unsightly damage.
The best way to anticipate a mineral deficiency is to do a soil test before planting your garden. Cauliflower is a heavy feeder, and boron is a micronutrient that is essential for growth.
Amending your soil as recommended in your soil report will help to ensure that essential nutrients are available.
To minimize direct sunlight exposure, choose “self-blanching” varieties that wrap their inner leaves around the developing vegetable to shield it from intense, browning rays.
If your variety does not self-blanch, clip long leaves together over the head when it’s about the size of your fist, to provide shade. Wrapping with its own leaves will also ensure adequate airflow, to avoid other problems such as fungal growth.
To inhibit insect damage, consider planting under floating row covers, applying diatomaceous earth as a preemptive measure, and keeping the garden weeded. Keeping insects at bay also goes a long way toward limiting the spread of diseases.
Broccoli and cauliflower may produce heads prematurely, resulting in small heads.
Buttoning can occur in young plants beyond the juvenile stage if they are exposed to several days of cold temperatures. Buttoning can also be caused by insufficient water, a shortage of nitrogen, excessive salt, or weed competition. To avoid buttoning, adjust planting dates in areas where chilling may occur, so that plants will either be large enough to yield a good-sized head or they will be too immature for premature heading when cold temperatures are likely to occur. Also, maintain a good irrigation and fertilization program.
Statewide IPM Program, Agriculture and Natural Resources, University of California
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As you grow cauliflower, you may come across a problem or two during the process. But that’s totally normal, as some of these problems are easy to solve and can be avoided with proper care. When you follow the basics, it will prevent common problems and help you reap a successful harvest!
I hope that this list of the problems with growing cauliflower gave you an idea of what you should watch out for as you grow this plant. Be wary about these problems so you can face them head-on if they ever arise or be sure to prevent them from happening to your crop.