Ranunculus Bloomingdale is not only a stunning variety, but
an indispensable item for early spring sales. Its bowl-shaped flowers resemble
small peonies and produce densely petaled blooms in nine colors: Pure Yellow,
Tangerine, Golden Shades, Pink Shades, Red Shades, Rose Shades, White Shades, a
mix and the new Purple Shades. The shade colors are very attractive with rich
color variation on each plant. Suitable for 4-inch and larger pots, the large,
full double flowers are borne on sturdy stems.
Stage One (day 1-14). Use
a sterilized soil media with plenty of organic matter, (a mixture of 30 percent
peat and 70 percent perlite has been found to be highly efficient and
accelerates germination and seedling growth. A pH of 6.0-6.5 is recommended for
best results. Cover seed with a very thin layer of soil or peat/perlite mixture
and water thoroughly. Select a well-ventilated environment and avoid strong
sunlight. Place seed flats in the coolest possible location in the greenhouse,
50-60º F. Never allow the growing media to dry out until the seed
Stage Two (day 15-21).
After seedlings begin to emerge, reduce moisture and place flats in a
well-ventilated and shaded greenhouse (2,000-3,000 foot-candles) and maintain
55-60º F days and 40º F. Apply a light fertilizer of 100 ppm nitrogen
to strengthen seedlings.
Stage Three (day 22-42). Maintain cool greenhouse conditions, and do not allow air temperatures
to exceed 77º F during this period. Fertilize every 10 days with 100-150
ppm nitrogen and maintain EC levels between 0.7-1.0 (saturated paste 2:1).
Ranunculus is sensitive to excess salt levels so avoid stressing the plants
with temperature and moisture.
Stage Four (day 43-50).
Seedlings have developed four true leaves and are now ready for transplanting
into pots. Ranunculus becomes reproductive at the fourth true leaf stage. Late
transplanting creates smaller plants with poor foliage and plant body
When seedlings reach the fourth true leaf stage, transplant
them into 4- and 5-inch pots with a starting soil pH of 6.0-6.5. Select a
highly fertile soil with good drainage, low in peat contents, with abundant
organic matter and well-rotted leaf mulch. Initial growth after transplanting
will be slow. It is important to maintain temperatures as low as possible,
55-60º F, never allowing daytime temperatures to exceed 77º F. Place
one plant per 4-inch pot and three per 5-inch pot, being careful not to damage
the delicate root system.
Approximately two months after sowing, plants will begin to
grow rapidly. Ranunculus requires high nutrition. Either incorporate fertilizer
into the potting medium or apply a commercial liquid feed every 7-10 days.
Water thoroughly and regularly, and if grown with heat, monitor the temperature
carefully. Young seedlings should not be subjected to long days, as this will
cause the plants to form corms, resulting in insufficient growth and bud
formation delay. Allow sufficient space between plants on benches to enable
maximum growth at all times. Also, monitor boron carefully as Ranunculus is
sensitive to low levels.
Approximately 1-1 1/2 months after potting, plants should
grow to a reasonable size. Crop time from sowing is 5-5 1/2 months, depending
on temperature. For early pot sales, maintain a daytime temperature of
60-68º F and a night temperature of 44-50º F.
At higher temperatures, both stems and leaves may show
excessive growth. Applications of B-9 at the rate of 2,500 ppm will yield good
results. B-9 should be applied when buds first show at the base of the plants.
To control flower stem stretch, lower temperatures, regulate watering and provide
good air circulation.
The most common insects are aphids, leaf miners and spider
mites. Major diseases include wilt, Botrytis and powdery mildew, all of which
can be controlled by spraying. Good culture and nutrition will create healthy
plants that are less susceptible to disease.
Growers often wish to produce an early crop of Ranunculus,
germinating and growing young plants in the heat and long days of summer. Under
these conditions plant growth often stalls or plants produce weak growth. This
is because under long days — greater than 13 hours daylength —
Ranunculus want to produce corms rather than vegetative growth. Providing black
out with 10-13 hours of day length will maintain active vegetative growth.
This double-flower plant now comes in a great new shade to complement the other eight colors.