Bowl of Arugula

Arugula is also known as rocket. It’s a leafy green full of nutrients like vitamins A, C, and K, as well as calcium and iron. This peppery green is popular in the kitchen and used in salads, sandwiches, and pasta dishes.

Best Planting Times

Planting MethodActivityRecommended Dates
Outdoor PlantingDirect SowingMarch 15 – April 30
Succession PlantingEvery 2-3 weeks through fall
Greenhouse PlantingYear-roundAdjust planting based on temperature control in the greenhouse

Planting Conditions

Arugula Planting Conditions

The varied climate across different regions allows for versatile planting times for arugula. With the elevation differences in Colorado, understanding local weather patterns is essential for successful growth.


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Useful Tools for Starting Arugula Indoors

Using the right tools can save you time and increase your success rate.

Seeds

Quality seeds lead to better germination and healthier plants. Starting with high-quality seeds gives your arugula the best chance to thrive from the very beginning.

For perennial plants, look for the wild rocket types. This type is slightly more spicy, but it will come back year after year.

The most commonly used type is the Astro variant.

Astro is a vigorous, all-season, cut and come again variety with long, silky leaves and nutty flavor.

You can find Astro Arugula Seeds on Amazon here: https://amzn.to/4gTTIgT

Planting Trays

Planting trays help you organize your seedlings and ensure they have enough space to grow before you transplant them outdoors. This makes the process more efficient and increases the chances of strong, healthy plants.
Planting Trays Image
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Grow Lights

Grow lights are essential if you don’t have enough natural sunlight. They provide your seedlings with the light they need to grow strong and healthy, even in less-than-ideal conditions.
Grow Lights Image
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Seed Starting Soil

Using light, fine soil specifically designed for seed starting helps young roots establish quickly and promotes healthy growth. It’s an easy way to give your seedlings the best start possible.
Seed Starting Soil Image
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Average First Frost Dates for Key Cities in Colorado

Plant arugula outdoors in Colorado approximately 2-4 weeks before the expected first frost date in late autumn to ensure optimal growth and flavor.

CityAverage First Frost Date
DenverOctober 15
Colorado SpringsOctober 10
PuebloOctober 20
BoulderOctober 5
Fort CollinsOctober 12

Disclaimer: Frost dates are average estimates, and actual conditions may vary. It is recommended to monitor local forecasts and adapt planting decisions accordingly.

Greenhouse Growing

In Colorado, utilizing a greenhouse can protect arugula from unexpected cold spells, allowing for earlier planting in spring and extending the growing season into fall. This controlled environment helps maintain consistent temperatures and reduce risks from pests and diseases, making it particularly beneficial during cooler months.

This 10×12 FT Greenhouse from HOWE is currently available on Amazon for $999.00.
Greenhouse Image 1
Greenhouse Image 2
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Fertilizer

For optimal arugula growth, supplementing with fertilizer can help ensure robust and healthy harvests. A quality fertilizer replenishes soil nutrients and encourages vigorous plant growth.
Fertilizer Image
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Other planting guides for Colorado:

Kale Planting in Colorado

Broccoli Planting in Colorado

Pumpkin Planting in Colorado

Any questions on growing arugula? Visit our forum to discuss: Gardening Forum.

General Care and Maintenance

Watering

  • Water arugula consistently to keep the soil evenly moist, especially important in dry climates.
  • Water at the base of the plants to minimize leaf wetness, helping to reduce fungal diseases.

Fertilizing

  • Apply a balanced fertilizer at planting, and again when the first true leaves appear. Incorporating compost can enhance soil fertility and structure.

Pest and Disease Management

  • Regularly monitor for common pests such as aphids and flea beetles. Vigilant pest management is essential, especially in warmer climates.
  • Use organic or integrated pest management methods to protect arugula plants from pests and diseases.

Harvesting

  • Harvest arugula leaves when they reach the desired size, typically 3-6 inches long. Regular harvesting encourages new growth and prolongs the harvest season.

In my garden, I try to plant arugula in both spring and fall for the best yields. It thrives in cooler temperatures. If you don’t have the time to start from seeds, you can find young arugula plants at local nurseries.

If you’re unsure about when to harvest your arugula, you can look for mature leaves that are at least 2-3 inches long. Regularly picking leaves can also promote new growth and extend your harvest.

Also, remember to check for pests like aphids and manage them promptly. With proper care and attention, growing arugula can be a rewarding experience that adds a delicious touch to your meals.

Starting Arugula Indoors

In cities like Denver (Zone 5b), begin indoor arugula seed starting between March 1 and April 15. This timeline ensures healthy seedlings ready for outdoor transplantation starting from late April to early May, taking advantage of the cooler spring temperatures.

Transplanting Arugula Seedlings

Transplant arugula seedlings outdoors from April 20 to May 10, ensuring the soil temperature is consistently around 45-60°F. Space the seedlings about 6-12 inches apart in rows that are 12-18 inches apart for optimal growth.

General Care and Maintenance

Watering

  • Maintain evenly moist soil, especially during hotter summer months, to support healthy growth and prevent bitterness.
  • Water at the base of the plants to avoid wetting the leaves, which can contribute to disease issues.

Fertilizing

  • Apply a light application of balanced fertilizer a few weeks after transplanting. Arugula benefits from nutrient-rich soil, so consider amending with compost before planting.

Pest and Disease Management

  • Keep a lookout for pests such as aphids, flea beetles, and slugs. Colorado’s climate can support these pests, so regular inspection is crucial.
  • Utilize organic pest control methods, such as diatomaceous earth or insecticidal soap, to manage infestations without harming beneficial insects.

Harvesting

  • Harvest arugula leaves when they are young and tender, typically 4-6 weeks after planting. Regular harvesting encourages new growth and prevents the plant from bolting.

The importance of good soil

Before starting to grow it is important to take a step back and find the condition of the soil in your garden,The optimal soil is a blend that includes the mineral-rich dirt along with organicrich organic matter that plants need to thrive.


In my garden I try to compost as mutch as possible, so I can mix in the nutrient ritch compost in my soil. I use both hot composting of food scraps and cold composting of all organic garden “waste”..
If you dont have the time or space for composting, it is possible to get compost ready to use in garden centers and Community Composting.
You can read more on Community Composting here: https://www.epa.gov/sustainable-management-food/community-composting

If you are uncertain of the quality of your soil, you can get easy to use soil tests at amazon for 17 dollars. Check latest prices here: Soil testing kit.

Also remember to check out how much sunlight your growing area gets, and that the rain drains well. If you treat your soil well and plan you crops according to your climate you will succeed with any plant you want.

 

FAQ

When is the best time to plant arugula in Colorado?

The best time to plant arugula is in early spring after the last frost or in late summer for a fall harvest.

Can arugula be grown year-round in Colorado?

Arugula can be grown in the cooler months, but it may not thrive during the peak hot summer months without proper shade or cooling measures.

What is the ideal soil temperature for planting arugula?

The ideal soil temperature for planting arugula is between 40°F and 65°F.

Do I need to start arugula seeds indoors?

It is not necessary to start arugula seeds indoors since they can be directly sown into the garden as soon as the soil can be worked.

How long does it take for arugula to mature after planting?

Arugula typically matures in about 30 to 40 days post-planting, making it a fast-growing crop.

What are the best conditions for growing arugula?

Arugula grows best in full sun to partial shade with well-drained, fertile soil and regular watering.

Can you plant arugula in the fall?

Yes, fall planting is possible. Sow seeds in late summer to enjoy a cool season harvest.

BeeJay