Are your cauliflowers producing heads that look like multiple separate florets rather than a dense curd? This problem is known as “cauliflower buttoning,” and it makes the heads look rather alien and unappealing.
Below are five ways that have been proven to lessen the chances of cauliflower buttoning. By taking precautions ahead of time, you’ll be less likely to contend with this issue once harvest time rolls around.
Before we dive in, let’s clarify a few things. First, the white head is what is known as the curd. We want a tightly packed curd rather than one that is loose and funky-looking. Also, buttoning, which is when the curd is loose, is different from bolting.
Bolting is when the plant goes to seed rather than producing healthy heads. This is a different problem, though many of the causes we talk about here will also cause bolting. The following image shows a cauliflower that has bolted:
With that out of the way, let’s talk about the first cause: macronutrient imbalances.
1. Ensure Proper Nitrogen Levels
Although we normally associate high nitrogen needs with green, leafy vegetables, cauliflower also needs a significant amount of it to develop properly.
As a member of the cabbage (Brassicaceae) family, it hoovers up about as much nitrogen as broccoli or rapini during its growth cycle.
A lack of sufficient nutrients in the soil can stress out your plants, leading to (you guessed it) cauliflower buttoning. Anything that offers these plants a less-than-ideal environment can freak them out, so they bolt instead of calmly producing dense, healthy curd.
Before you plant your cauliflower, run some soil tests to check the nitrogen levels. If they’re below 40 ppm, you’ll need to amend with nitrogen fertilizer, such as blood meal, until they’re in the 40 to 60 ppm range.
Just make sure that you don’t add too much nitrogen, as doing so will promote more vegetative (leafy) growth rather than encouraging floral curd formation.
2. Water Consistently
Cauliflower buttoning can also occur if your plants are watered inconsistently. They like to have consistently moist soil, so aim to adhere to a regular watering schedule. Water your plants at soil level early in the day, decrease watering during rainy periods, and increase it when the weather is hot and dry.
By doing so, you’ll ensure that they uptake enough water to stay healthy rather than getting waterlogged or drought-stressed. If and when they get too much or too little water, they’ll get stressed and bolt. They’re tetchy and need to be babied for optimal production.
You can avoid water build-up around the roots by ensuring that you’re planting in well-draining soil. Amend your cauliflower beds with plenty of perlite or volcanic rock if needed.
Alternatively, if you often deal with drought-like conditions instead, work coconut coir or vermiculite into the soil to assist with water retention, and spread coconut or straw mulch around your plants as well.
Read our article on coco coir and learn why it’s so ideal for soil amendment and mulches.
3. Prep for Unexpected Heat Waves
Although none of us can control the weather, we can try to plan for potential heat waves so we can protect our plants accordingly.
Like other brassicas, cauliflower thrives best in cooler weather. This is why it’s often cultivated in early spring or autumn rather than at the height of summer. When temperatures get too high, the plants bypass curd formation and produce seeds quickly.
As such, one of the main culprits that cause cauliflower buttoning is a sudden, unexpected heat wave just prior to curd formation.
When and if temperatures suddenly spike above 80°F/27°C, the cauliflower will get confused. It doesn’t know whether it’s supposed to bolt into seed production or continue toward curd formation instead.
As a result, you’ll end up with a combination of the two: bolted florets with button-like tops.
Keep shade cloth on hand so you can draw it over your plants if and when a heat wave strikes. While this won’t cool the surrounding temperatures much, it protects plants from the sun’s rays.
Additionally, you can fold the outer leaves over the forming heads and secure them there like little hats; this should help to keep them cool until the heat wave breaks.
4. Avoid Late Planting
Much like the issue above, this has to do with heat exposure. Unlike the above issue, however, it isn’t an unexpected heat spike so much as an attempt to grow cauliflower in inappropriate conditions.
The best temperature range for growing these plants is 50-70°F (or 10-21°C). They do best around 60°F/16°C, getting cool overnight temps and sun without too much heat at midday. If you want to avoid cauliflower buttoning, research when your area will see these temperatures.
Once you do that, you can plan your planting accordingly.
If you’re starting cauliflower from seed, you must start them six to eight weeks before your area’s last frost date. This way, you can get your seedlings into the ground the second your area is cleared for planting. By doing so, they’ll hit their curd-formation period when temperatures are optimal.
In contrast, if you wait too long to start your seeds, you’ll miss that window and risk the chance that your plants will button rather than form dense, perfect heads. If you’ve missed the best window for seed starting, pick up some seedlings from your local nursery and plant those instead.
5. Protect Plants from Sudden Cold Snaps
Cauliflower buttoning isn’t only caused by unexpected heat waves: a sudden cold snap can also cause your plants to panic and bolt into buttoned florets. As mentioned, these plants are sensitive to temperature fluctuations and bolt if their growing conditions aren’t ideal.
Keep rolls of horticultural fleece, aka frost cloth, on hand and watch the weather forecasts diligently. Should you get a warning that a few days’ cold snap is approaching, cover your cauliflowers at dusk and uncover them again once the day starts to warm up.
By doing so, you should be able to avoid buttoning and maintain consistent temperatures for ideal curd formation.
If you don’t have the budget for horticultural fleece, you can make do with what you have. For example, burlap isn’t ideal but can make do in a pinch. If you have a relatively small cauliflower patch like I do, you can cover them with flannel bedsheets or light blankets.
Does Cauliflower Buttoning Make the Plant Inedible?
One of the things people ask about cauliflower buttoning is whether it renders the head inedible. This depends on several factors, but the short answer is “not necessarily.”
Although the curd isn’t dense, there’s usually nothing actually wrong with the florets: they just look weird and may have a slightly different texture if you eat it raw.
The only way flavor may be affected is if it has developed some bitterness due to bolting during a heat or cold wave. This can often be lessened or eliminated by blanching. Your best bet is to taste a floret raw, and then determine whether you think you can eat it or not.
If you’re growing cauliflower for your own family to eat, then as long as it isn’t discolored, squishy, or stinking, you should be good to go. Boil it, roast it, mash it, or pickle it to your heart’s content. These florets, although misshapen, are still an excellent source of vitamins and dietary fiber.
In contrast, if you’re growing these plants to sell at a local market, then you should probably cut your losses. Keep this harvest to yourself rather than trying to sell it, as most people are super picky about the produce they buy. Freeze or pickle it and consider it a pantry stuffer rather than a commercial crop this year.
Alternatively, as long as the cauliflower buttoning hasn’t affected your crop’s flavor, you can always process the buttoned florets into cauliflower “rice.” Since this is so popular with the keto, paleo, AIP, and Whole30 crowds, you may still be able to reap some reward from your hard work in growing all of these plants.
