How To Plant Ranunculus Corms

Ranunculus are a striking and attractive variety of flowers that feature multiple layers of petals in several colors and sizes. Though a popular garden addition, they are cultivated mainly as cut flowers. They develop from corms, and we've researched all you need to know about growing ranunculus flowers.

Ranunculus develop from bulbs or corms that need to be soaked for 3 to 4 hours in room temperature water prior to planting. Once they swell, you can plant them directly on raised garden beds or in containers with organic-rich soil and a balanced fertilizer.

Ranunculus are cool-season flowers best sowed during the fall in areas with full sun exposure.

Growing ranunculus corms requires proper preparation (soaking and pre-sprouting) and growing conditions. The article aims to guide you with the ways on how you can properly grow the plant. Read on and find out tips and ideas that can surely help you!

Ranunculus asiaticus or persian buttercup. Presoaked ranunculus corms planted in a propagation tray. Ranunculus corms, tubers or bulbs., How To Plant Ranunculus Corms

Picking And Preparing Ranunculus Corms

Corms are specialized plant structures serving as storage organs for simple sugars and water necessary for surviving extreme weather. They have a tough external coat, or tunic, that acts as a protective covering from flooding, drought, insects, and pests.

Once introduced into the ground, they develop roots and grow buds that eventually form the entire plant structure. Corms are dormant and can be stored for long periods and they are available in most nurseries.

Large corms contain higher amounts of stored energy and will yield vigorous plants with bigger, brighter flowers.


Dried ranunculus corms. Preparing flowers for planting.

The ranunculus corms will appear dry, wrinkled, and hard due to dormancy, but they have the potential to develop into attractive, colorful blooms. Soak them in room temperature water for 3 to 4 hours until they swell and almost double in size.

Sprouting ranunculus corms in a seed tray.

You can change the water every hour to avoid stagnation and never go over the recommended soaking time to prevent them from rotting. You can then plant them directly on garden beds or containers.


You have the option to pre-sprout the corms in seed trays before planting them in gardens or containers, as this will cause the blooms to appear sooner.

Fill a tray with 1 to 1 1/2 inches of loam, peat moss, and coarse sand or perlite mixed thoroughly. Then, moisten the medium moderately. Place the pre-soaked corms a few inches apart from each other then cover them with 1 inch of the same mix.

Store the tray in a cool, dark area for at least 10 days or when the roots begin to emerge. You can now transfer them on garden beds or appropriately sized pots or containers.

How To Plant Corms On Raised Garden Beds

Planting ranunculus corms directly on raised beds gives you the option to incorporate the plant into your garden or landscape. Once in full bloom, they create an attractive hedge or accent to your yard.

Prepare The Planting Medium

Prepare the planting medium and the general environment where the corms will grow. A raised garden bed should be at least 6 to 8 inches high and must be slightly angled on all sides to keep the soil intact - installing edging is also an option.

Since the plant requires moist environments, grow the corms in a rich, well-draining soil. This way, root rot can be prevented, and the garden bed will not be waterlogged.

If the plot dries quickly, add a layer of mulch to retain soil moisture. Remember to use the recommended potting mix to facilitate healthy growth and development.

Check out Coco Peat Perlite Potting Mix on Amazon.

How Far Apart To Space Ranunulcus Corms?

It is necessary to plant the corms 2 inches deep and 9 inches apart to accommodate their growth and to allow proper air circulation that generally helps regulate moisture. This way, you can prevent fungal infection and root decay.

How Much Light Do Ranunculus Need?

The garden bed must be located in an area where the corms can receive full light exposure. Note that although the plant requires direct sunlight, it will not grow well if temperatures are high.

If such situation ensues, it is ideal to cover the plants with shade cloth to keep temperatures at the desired level and provide protection against extreme light and heat.

How Often Should I Water Ranunculus Corms?

A moist growing medium is the ideal environment for corms. Hydrating requirements can be fairly tricky since overwatering may cause root decay while lack of moisture may kill the plant.

To address its watering needs, give the plant a thorough hydrating once the first 2 inches of the garden bed is dry. It is not necessary to water the plants if the soil beneath the top surface still feels wet.

You may add a layer of mulch or compost in between the plants to ensure that the garden bed retains adequate soil moisture.

What Temperatures Can Ranunculus Handle?

Ranunculus corms are cool-season plants that find it difficult to thrive and grow in temperate regions. To promote blooming, the ideal temperature is below 70 degrees Fahrenheit. If the climate is too warm, the plant will begin to go dormant and stop producing buds.

Alternatively, if the temperature is below freezing, the corms might die back. Cover the garden bed with a fabric tunnel made with wired hoops and frost cloths to protect it from winter frost. If the temperature is above freezing, you could remove the cloth to expose the plant to sunlight and wind.

Check out Plant Covers For Freeze Protection on Amazon.

Air Circulation

Ranunculus flowers are susceptible to fungal infestations such as powdery mildew, which thrive in moist and compact environments. Proper spacing between corms would prevent overcrowding and promote good circulation between shrubs and hedges.

When Should You Fertilize Ranunculus?

Feed the plants with fertilizer that has equal amounts of NPK twice a month during the growing season to facilitate and promote blooming. Nitrogen helps in leaf development necessary for the process of photosynthesis.

Phosphorus will improve nutrient and water uptake because it aids in the development of the plant's root system while potassium balances the overall growth of below soil and overground parts of the plant.

Liquid fertilizers tend to accelerate and complement ranunculus corms to produce blossoms with rich, vibrant, and deeper colors.

Before transplanting the corms, organic fertilizers such as compost and mulch can be added into the soil mix since they provide basic nutrients. This way, it is not necessary to feed the plant with inorganic fertilizers.

How To Plant Corms In Containers

Container planting involves the proper ratio and spacing between corms and the available area for growth.

What Type Of Potting Mix Is Best For Bulbs?

The potting mix should contain a portion of organic matter that provides the basic nutrients and inorganic component that permits proper drainage.

Organic content should include compost, peat moss, and shredded coconut husk. These materials generally contain the macro-nutrients - Nitrogen, Phosphorus, and Potassium- needed for healthy growth and development.

Amending the soil with inorganic materials such as coarse sand, pumice, pebbles, and crushed granite promotes proper drainage to loosen the soil and allow the roots to breathe and develop.

Fill the container with a mixture of organic and inorganic materials mixed in equal proportions. If the pots are small, the corms should be individually planted, otherwise the root system will compete for space and nutrients.

It is advisable to plant one corm in an eight-inch diameter pot, two per 12 inches and three per 18 inches to promote proper spacing.

When Does Ranunculus Bloom?


Flowers emerge two to three months after planting which tends to last between four to seven weeks. If given the proper growing conditions, the plants will produce large root balls; that's why it is important to give the corms adequate depth and spacing.

Garden Soil Vs. Potting Mix: Which Is Better For Ranunculus?

Garden soil pertains to compact and heavy soil that tends to clump and restrict root development. It can be amended with compost and mulch to make the medium more appropriate to accommodate plants and other vegetation.

A good potting mix contains proportions of organic and inorganic matter to facilitate plant growth. It can be amended to make the soil appropriate for the plant.

It is better to grow the corms in a potting mix since it includes necessary nutrients and promotes proper drainage. You can control, balance, and amend soil composition to make it into a more complete medium.

Which Way Up Do You Plant Ranunculus Corms?

Ranunculus asiaticus or persian buttercup.

The claw-like structure should be planted facing the ground since its base is where the roots will develop. Remember to soak the corms before planting. Container-grown corms do not necessarily require deep pots since they have shallow root systems.

In Closing

Ranunculus corms require soaking and pre-sprouting before planting to stimulate its system right after dormancy. Once the corms swell, they can already be planted. We hope the article helped you with the ways on how you can properly grow your corms.

These topics might also interest you:

Why Are My Ranunculus Corms Not Sprouting?

Does Potting Soil Have Fertilizer In It?

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