Arugula is a cool-season plant that doesn’t do well in hot temperatures, full sun, or dry soil. Any or all of these conditions can cause the plant to bolt or go to seed.
Once it starts to flower, the stems and leaves of arugula turn bitter, and there’s no stopping the bolting process.
Why is my arugula bolting? The two main reasons that arugula bolts are high temperatures and delayed harvesting. If there are a few days of high heat in a row or you let the soil dry out, it will start to flower. The same goes for allowing the plant to grow without harvesting. Flowers appear, and the plant turns bitter.
Read more to find out the main reasons arugula bolts so quickly, how to slow or delay the bolting process, and the best times to harvest it.
Arugula Bolting – What To Know
When arugula plants go to seed, otherwise known as bolting, there’s no turning back the clock on this process. As the flower buds open everywhere, the stems and leaves become bitter.
Although you might find a recipe or two online for bitter arugula, most people would give up on any more arugula harvesting and call it a season.
What Does Bolting Arugula Look Like?
When arugula plants start to bolt, they don’t flower straight away. Instead, they grow small lobeless leaves that are short and slender like weeds. That’s the first sign that your arugula is going to seed.
This is followed by the flowers themselves. The flowers are often white with four separate petals that look like clover leaves. There’s a thin dark line in the middle of each petal.
Some people recommend pinching off the flowers to slow the bolting process, but that won’t stop the plant from getting bitter.
What Causes Arugula To Bolt?
Not all arugula plants will bolt right away. It all has to do with the temperature, watering, weather conditions, and plant stress. Here are these causes in more detail.
- High Temperatures: As a cool-season plant, arugula thrives in daytime temperatures between 45 and 65℉. If the temperature goes above 65℉ for a few consecutive days, the plant will bolt. If you have a short spring, consider planting arugula in the fall.
- Full Sun: By nature, arugula plants favor shade over full sun. If you plant them in a sunny spot, there’s a good chance they would bolt right before their time.
- Dry Soil: This is often an overlooked reason. Arugula prefers moist soil. This ensures that the soil temperature stays cool. Add mulch to keep the soil moist and prevent premature bolting.
- Stress: Arugula plants could go through stress due to a lack of nutrients in the soil. This triggers the plant to go to seed as a self-preservation mechanism. Add a generous dose of organic compost to the soil before planting arugula.
- Changing Weather Conditions: If the weather changes abruptly between hot and cold, this can stress the arugula and cause it to bolt.
Can Bolting Be Stopped?
Bolting is a natural phase in the arugula’s life cycle. In a way, this is the mission of the plant. To flower and seed is the reason for all the lush and succulent leaves.
Once the arugula bolts, there’s no stopping the process or reversing it. Even if you try to slow it down, the stems and leaves will turn bitter anyway.
Can You Eat Arugula After It Has Bolted?
For some people, a little bitterness in the arugula wouldn’t stop them from enjoying it. There are many recipes for bitter arugula that allow you to harvest the plant after it has bolted and cook it.
What Do You Do With Bolted Arugula?
When arugula bolts, you can uproot most of the patch and throw it in the compost bin. The rest of the arugula plants can be served in many dishes and recipes.
The flowers have a sharp spiciness that can add flavor and taste to your salad. The same goes for the immature seed pods. They do well with salads.
If you allow the seed pods to mature on the plant, you can grind the seeds and use them as a spicy condiment to add to your marinades, salsas, cooking, and salad dressing.
Arugula Growth Stages
The arugula plant goes through the same growth stages as many other plants in the same genus and family. It takes the plant 40 days from the time you plant it to be ready to harvest.
You should continue to harvest the new leaves as they develop to prevent premature bolting.
Signs That Arugula Is Going To Bolt
If you are worried that your arugula patch is going through stress over the changing weather or a recent heat wave, keep an eye out for the small weed-like and lobeless leaves that emerge instead of the regular lobed leaves.
That’s a sure sign that your arugula is going to bolt.
Once these weedy leaves emerge, the plant will turn bitter and flower buds start to develop. You can harvest as much as you can of the still-edible leaves at this point.
Slow Bolt Arugula
Not all arugula varieties will bolt when the weather warms up or the temperature goes above 65℉. Some varieties are heat resistant and won’t bolt so quickly. These are:
- Astro: Astro arugula is a heat-resistant and slow-bolting cultivar with a fast growth rate. It reaches maturity within 30 to 40 days and has a mild flavor.
- Slow Bolt: This variety has a moderate spiciness and is more heat tolerant than Astro. It matures within 40 to 45 days and has broad lobed leaves.
- Wild Arugula: It has an excellent heat resistance and is slow to bolt. The leaves have a sharp spiciness to them, but they’re still edible even after the arugula bolts.
- Bellezia: One of the mildest tasting arugulas that resist the heat and are slow to bolt. It has a nutty flavor but takes about 50 days to mature.
When To Plant Arugula
Depending on the arugula variety you grow, you can enjoy two arugula seasons a year.
If you have a long and mild spring, you can start arugula seeds in the early spring. Some varieties like Slow Bolt arugula can be harvested as baby leaves 21 days after planting.
The other time to plant arugula is in the fall. Give the plants enough time to mature before the first frost.
Tips To Delay Arugula Bolting
Once you understand what triggers premature bolting in arugula, you can make sure to avoid these triggers and give your arugula a long season.
Besides growing slow-bolting arugula, you can follow these tips to delay arugula bolting.
- Plant in the Fall: If your arugula plants tend to bold quickly during the spring season, switch to fall planting. This will delay bolting and give you a long harvest season.
- Mulch: One of the bolting triggers in arugula plants is when the soil dries fast and its temperature rises. Improve water retention by covering the soil with a thick layer of mulch.
- Water Regularly: Keep the soil moist, especially as the temperature starts to rise. This will keep the soil cool and prevent premature bolting.
- Shade: As a cool-season plant, arugula prefers partial shade over a sunny spot.
- Fertilizer: The lack of nutrients in the soil can cause the plant to go to seed, so mix organic compost with the soil before planting the seeds.
You should start harvesting arugula leaves as soon as they develop. That way you can delay bolting since the plant has to grow new leaves to replace the ones you keep harvesting.
Some arugula cultivars can be harvested as early as 21 days after planting. These baby arugulas have a succulent texture and mild flavors.
Can You Harvest Arugula After It Flowers?
You can still harvest arugula after it flowers and use the leaves and flowers in dishes and salads. Mature arugula seeds go into marinades and salsas and can be used as a condiment.
Does Arugula Grow Back Every Year?
Wild arugula is a perennial plant that can survive moderate winters and mild frost, but garden arugulas with their many varieties are annual plants that die after the seeds mature.
Wrapping It Up
When arugula plants bolt, there’s no turning back. The white flowers and lobeless leaves signal the plant’s transition to the seeding phase.
Delay arugula bolting by watering regularly and mulching. Some slow-bolting varieties can resist heat and give you a long harvest season.