Ranunculus Breeder

How to grow Ranunculus

Ranunculus loves cool and sunny conditions. You can plant and grow them where they are protected from frost or not-too-sever cold conditions. They are perenials, so that you can grow them for long. But in Japan, humid conditions make tuber rotten, so you need to dig up tubers before rainy season starts in June. Clean the tubers to prevent disease and dry them for 2-3 days on sunny days. Keep them in cool-and-dry conditions until planting season in October.

General instructions

  • Plant tubers after the temperature falls under 20 degree C.
  • They prefer cool condition, but protect from frost.
  • They need to have cool condition to develope flower, so Okinawa region is not suitable place to grow ranunculus, as the climate there is too warm.
  • Remove spent flowers as the fallen flower petals may cause some mold to the plant.
  • Dig up tubers after the blooming has finished and stems become brown. It should be done before rainy season
  • Keep tubers in cool-and-dry conditions, as they are easily rotten. You can keep them in a refrigerator.

Planting and growing plan

(depends on the region's climate)

Ranunculus in open airGrowing in open air

Comment from Ranunculus beginner

I cannot see such a wide range of flower colors in other plants, also they are very beautiful.
One bulb produced so many flowers and I could enjoy them for a long period. I heard growing ranunculus in Japan is very difficult, but I could succeed by following the instruction. But in some places, stem are too short for cut flowers. I wonder I should have protected them from cold temperature during winter. Or other reason ?
I would like to try again this autumn. (photo taken in Kumagaya city, Saitama on 2009/05/08)

Ranunculus in open air2nd year

I made it ! How beautiful these flowers are !
During cold winter, I protected small plants by covering them with plastic film tunnel. Then, stems grew longer and the blooming started one month ealier than the previous year.

(photo taken in Kumagaya city on 2010/04/18)

How to grow

1. Planting tubers

mid. Oct. ~ late Nov. (in Kanto region)

Image description We recommend to plant tubers in pots or planters. It's also possible to plant them in the open air where frost-free, sunny conditions. Before planting, pre-treatment is necessay to rehydrate them. Soak them in water overnight or wrap them in a wet towel and keep in a refrigerator. Be sure not to use warm water, as the tubers absorb water too rapidly and may cause rot.
Plant tuber with right position, growth point upside and toes point down. (white part is growth point in above picture.) Prepare horticultural perlite, or the soil should not be too heavy. Plant the tubers 1-2 cm deep for pot and planters, 5 cm deep and 15 -20 cm wide in open field. Give watering sometimes until they germinate.

2. Repot / Replant

mid. Nov. - mid. Dec.

Image description The tubers germinate and when the plants grow big enough, it's time to replant them in planters or outdoor beds. Use good quality and well-drained soil, adding organic material such as leaf mold.

While the plants are growing, fertilize them sometime.

Give thorough watering when the soil is dry, but overwatering may cause them rot. Well-grown plants during winter produce many flower buds. If you see the plants are so small, pale color leaves, weak stems, then you need to feed them more fertilizer. During blooming period, lack of water may cause small and poor flower. Give watering not to be too dry.

3. Bloom

early Apr.~ early May

Image description Flowers start to bloom, then please enjoy cut flowers, they last rather long time in the vase. Remove spent flowers and dead leaves, as the fallen petals may invite some mold.

4. Dig up tubers (before rainy season)

Mid. May ~ Mid.June

Dig up Ranunculus Dig up tubers after the stems and leaves become yellow/brown. If the tubers are left in the soil, they may become rotten, as the climate in Japan is too humid. Bend the stems at the base by hand. If the tubers is so big, then divide them into smaller pieces by twisting slowly and releasing tangled roots. Be sure not to hurt growth point, so no need to divide them if you think they are too tightly tangled.

Image description Wash away soil and dust from the tubers by water.(To protect from disease, it's more safe to soak them in bulb sterilizer for 2-3 min.,if you have.) Dry them for about 3 days on sunny days.

Kept in stock

June ~ Oct.

Image description Put them in paper bags and keep them in cool-and-dry environment. Too much moisture may cause mold. Actually, it is rather difficult to keep them in good conditions in Japan during hot and humid summer. Some people keep the tubers in the refrigerator. (not freezing temperature please)

Please enjoy growing Ranunculus next season again !

June ~ September

Tubers are digged up and kept in cool-and-dry conditions

Ranunculus stock