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Carrot. Daucus carota
Family: Umbellierae
Origin
Carrots originated in Afghanistan and possibly northern Iran and
Pakistan. By 900 -1000 AD the domestication of purple and yellow
carrots had been spread from Afghanistan to the eastern Mediterranean.
In fact, the Greeks called the carrot "Philtron" and ate the carrot because they believed it was a
love medicine--making men more ardent and women more yielding. The Roman emperor
Caligula, believing these stories, forced the whole Roman Senate to eat carrots so he could see
them "in rut like wild beasts." In the 1300s doctors prescribed carrots for everything from sexual
maladies to snakebite. During this time purple and yellow carrots in began to appear in western
Europe and China. From thence, carrots moved to England, during Elizabethan times some
Elizabethans ate the roots as food; others used their feathery stalks to decorate their hair, their
hats, their dresses, and their coats. In the 1600s: Yellow carrots were developed in Japan. In
addition to purple and yellow, white carrots were reported in the 1700s in Europe with an orange
type first reported in The Netherlands and adjoining regions. Today the orange carrots
predominate world-wide although some white types persist in western and eastern Europe (for
livestock), some red (not orange) in Japan, some yellow and purple in the Mideast, and some
purple, yellow, and red from Turkey to India and China. In Bhutan the carrot is a recent crop and
has as yet to gain popularity.
Utilisation
Culinary
For the Bhutanese, it is a new crop, so not used much in cooking. They are used in the
preparation of soups, stews, curries, pies and, tender roots may be pickled. Carrots can also be
used as an ingredient in baking, making puddings, cakes and muffins. Other uses for carrots
include using them as a garnish, juice, in salads and coleslaw, steamed, dried, canned, frozen and
sautéed.
Carrots are an excellent source of vitamin A and Fe. In western countries most children have
grown but with the tradition of being told “eat your carrots so you can see in the dark” this has
probably resulted from an association being made between vitamin A deficiency which causes
night blindness and carrots high vitamin A content. The folk belief that carrots enable one to see
in the dark--or at least improve vision--enabled the British Royal Air Force to disguise its use of
radar from the Germans during World War II. The story goes that the Air Force bragged that the
great accuracy of British fighter pilots at night was a result of them being fed enormous quantities
of carrots--and the Germans bought it because their folk wisdom included the same myth. Carrots
also have good quantities of vitamins A, B and C, and are rich in sugar.
Medicinal
In Europe as early as 1000 BC where it was grown as a medicinal plant, used to treat
stomach problems, wounds, ulcers, liver and kidney ailments. Carrots are a super
source of beta carotene, a powerful anticancer, artery-protecting, immune-boosting,
infection-fighting, antioxidant with wide protective powers. Carrots protect humans
against; Fill in blanks in class
1. .
2. .
3.
4. .
5.
6. .
7. .
Companion planting
Good garden companions when planting carrots are Peas, lettuce, chives, onions,
leeks, rosemary, sage, tomatoes, Bush beans, Brussels sprouts, cabbage, onions,
peppers, red radishes. Sage planted with carrots will enhance the carrots growth.
Avoid planting carrots in proximity of Pole beans, strawberries, and especially Dill as
it stunts their growth.
You will often see the suggestion that growing onions in between the carrots keeps
the carrot fly at bay. The idea is that the onion smell fools the female fly, which is
otherwise attracted by the lingering foliage scent after carrot thinning. Alas this lovely
romantic idea rarely works in practice. Onions can only be effective when the onions
are in active leaf growth. Best results come from four rows of onions for every one of
carrots and the beneficial effects will diminish as the onions start to bulb.
Other strongly scented plants such as French or African marigolds,
pennyroyal and garlic have all been suggested in the past, but have
insufficient data to back up their claims. Mix carrot seed in with a
packet of mixed annuals and sow as usual. A mixed crop should
sustain less damage than a monocrop.
Other uses
Certain varieties of carrots have been used as feed for horses and
dairy cattle.
Botany
General characteristics & classification
The carrot is an erect biennial grown as an annual with a swollen tap root which
varies in shape, size and colour. Carrots were traditionally classified by Swiss
scientists in the 15th century according to colour, notability into purple to yellow, to
red orange types now they are classified into the Chanteney, Danvers and Nantes
groups.
Leaves (Top growth)
After the emergence of the cotyledon leaves, two kinds of leaves are formed. The
lower leaves are pinnate and linear or lanceolet, and are fine and lacy in appearance.
The upper leaves are smaller and less divided.
Flowers & seeds
Flowers: The inflorescence is a compound umbel and the flowers are white and small.
The white flowers are perfect, and require cross-pollination for seed set. Most often,
the plant will not initiate a flower head until the second year of growth and a chilling
period.
Seeds: Seeds are tiny (one teaspoon can hold up to 2000 seeds), and covered with a
spiny, hooked, and slightly curved mericarp. The mericarp contains a characteristic oil
which inhibits seed germination, requiring the removal of the mericarp before
planting.
Roots
A tap root system develops from the seeds hypocotyl. Top growth, supplies
carbohydrates to the swelling hypocotyl and together, the hypocotyl and the tap root
form the ‘Carrot Root'
Figure.1. Left; Swollen tap root of the carrot, Right; Carrot flower, leaves & seed mericarp
Ecology
Climate
Temperature: Carrots are a cool season crop, having optimal growth between 1518°C, with a minimum of 7°C and a maximum of 24°C. Crops to be grown in the
fall can be started in the heat of the late summer to ensure that a substantial period of
cool weather exists before frost. Carrots can be sensitive to high soil temperature.
Colour development is determined by temperature. Maximum colour development
occurs in the 15-24°C optimal growth range. Temperatures higher or lower will cause
a lighter root colour. Temperatures over 21°C will also reduce root length, while
temperatures below 15°C will produce longer roots. Tropical varieties are able to
tolerate warmer conditions.
Rainfall: Many cultivars tolerate a range of rainfall but excessive rainfall may
adversely affect root colour.
Soil
Well drained, light soils such as coarse sand or friable loam rather than heavy clay
soils is better as this allows for uninhibited root growth. Loose fine soil with good
water holding capacity and pH of 6.5-7.5 is preferred.
Varieties
There are two main groups of cultivated carrots: the eastern (anthocyanin) carrot and
the Western (carotene) carrot the main types offered for sale in Bhutan are as follows.
Eastern Carrot
Early Nantes: Is a European variety that is mainly used for its roots. Roots are
cylindrical orange in colour and have a delicious tender taste. Outside of Bhutan it is
mainly used for home or farmer market or roadside stands, although can also be
grown for commercial fresh market and processing. From seed to harvest the growing
cycle usually takes on average 120 days.
Chantenay: An attractive deep reddish orange carrot with smooth outer surface.
Outside of Bhutan it primarily used for processing due to its excellent yield recovery.
Not generally used for fresh market because of coarse raw product root texture. It is a
heavy yielder and matures in 120 days.
Hybrid
Pusa kesar: released by the Indian Agricultural Research Institute (IARI) was selected
from a cross between Local Red and Nantes.
Chantenay
Early Nantes
Cultivation Operations
Field preparation
Prepare deep loose soil at least to a depth of 2.5cm. Prepare a raised bed of 90 cm
wide, 15cm high at any convenient length. To produce quality carrots, all clods, hard
lumps, plant debris, and the like should be removed from the soil to prevent forking or
root stunting.
90cm
c
mcm
15cm
Seed Sowing
High altitude
Mid altitude
Low altitude
Altitude Jan
(m)
High
altitude
Mid March to 1st week of July
Oct to Jan
Oct to Nov
Feb
Mar
Apr
May
June Jul
Aug
Sep
Oct
Nov
Above 2000
Mid
altitude
1000-12000
Low
altitude
Below 1000
Spacing: Sown in lines of 15 cm row to row and 5-7 cm plant to plant.
Seed rate: 2.0- 2.5 kgs/acre of seeds. Twisting and intertwining of carrots results from
sowing seedlings too thickly. For a continuous harvest be sure to sow a new of row
carrots each month.
Sowing method: Using a hoe handle, stick or similar object, make a furrow one centre
metre deep down the centre of the ridge. Plant seeds 1cm, deep, 15cm row to row
and 5-7cm plant to plant. Cover lightly with loose soil and sprinkle with water. Plants
should come up in 10 to 15 days.
With the seeds being so small it is almost impossible to place the seed at the correct
spacing. You can avoid excessive waste of seed and the extra work involved in
Dec
thinning by mixing the seed with a bulk material. For example washed river sand
mixed with the seed provides more bulk and makes sowing easier. Alternatively you
can mix seed from some of the shorter growing radish varieties (30 day life cycle)
with carrot which has a 120 day life cycle. This provides bulk thereby making
planting easier and the radish crop will mature earlier than the carrots and thinning is
carried out automatically as the radish is harvested.
Management
Manures & Fertiliser
Do not add compost or manure to the carrot beds prior to planting unless it is very
well decomposed, as too much nitrogen will encourage roughness and branching.
Branching/forking and roughness results from high nitrogen levels in the manure or
compost burning the root tip which responds by fanging. One way of best ways of
optimising the use of the land is to grow carrots after a greedy (high nutrient
demanding) crop such as lettuce, broccoli and cabbage. This is because soils that have
previously received liberal applications of organic matter are ideal for a follow-up
crop of carrot. Once the sites been selected apply 10:20:20 NPK kgs/ acre as basal
dose and follow up with a top dressing dose of 10 kgs of nitrogen after thinning.
Thinning & Banking soil
Thinning: With the seed being so small it is almost impossible to space the seed at
the correct spacing at sowing, it is likely that the crop will need later thinning as
double sowing seeds at the time of sowing is almost impossible to avoid. Thinning out
(removing some seedlings to avoid over-crowding) should begin when the seedlings
are about 2.5cm high. Thin the main crop carrot seedlings to 5cm apart, early variety
carrots to 7cm apart. Twisting and intertwining of carrots can also result from
inadequate thinning of seedlings. Thinning out the seedlings will release the scent of
carrots, and attract the attention of carrot fly. To avoid this, perform this activity in the
evening when the carrot fly is not about. Ensure that any soil disturbed by the thinning
process is firmed back down with your hand - carrot fly lay their eggs in loose soil
around the carrot.
Banking: “Sun burning” (carrots turning green at the crown) can be avoided by
pulling a small amount of loose soil up to the row when the roots are swelling (about
40 to 50 days after planting). “Sunburning” causes a dark green colour to develop on
the exposed crown, and this in turn creates an off flavour when cooked.
Learning Exercise 1.
A farmer has 4 hectares of land in Paro and wishers to plant carrots. He is looking to
extend his harvest as long as possible and also intercrop his carrots with another crop.
Further more the farmers land is used for the production of other vegetables outside of
the carrot season.
1. State how many carrots the farmer needs to plant.
2. What is the alternative crop and how many does you need to also plant..
3. When must sow he the seed and at what spacing.
4. What are his expected yields and when should you expected to see a harvest
both from the carrot and from the alternative crop.
5. Finally state what crops should the farmer plant when carrot is not being
grown on the land.
Weeding & Hoeing
Once the carrot crop is sown only a small window of opportunity exists to control
weeds. Weeed generally germinate at a faster rate than the carrot crop so hand weed
directly after sowing. If you are planning to use chemical controls then the gap
between the weed germination and carrot germination is the time to do it. After this
period the only options for weed control will be hand weeding as and when there is
weed pressure
Plant protection
Carrot fly
Black rot
Swift moth
Irrigation
Critical Growth Periods: Carrots are most sensitive to moisture stress during root
enlargement and seed germination. Irrigation can improve emergence, reduce wind
erosion, and lower temperature at the soil line during germination. Carrot yield, like
beets, radishes and onions depends on production and translocation of carbohydrates
from the leaf to the root. Moisture stress is reported to cause small, woody, and poorly
flavoured roots. Irregular watering can also cause rough, lumpy, carrots with obvious
growth rings. Water stress may also cause growth cracks and cracking often occurs
when watering after the plant has suffered from water deficiency.
Harvesting & Handling
Harvesting
Carrots can be harvested at various stages of development. Carrot thinnings can be
added to fresh salads and eaten green tops and all. "Thinnings" are immature carrots
pulled from overcrowded rows to make room for others to grow. Finger-size carrots
may be dwarf carrots or immature average ones. They can be very tender and sweet.
Harvest carrots before they are over mature, about 2.5 to 4cm in diameter. Huge
overgrown carrots are less tasty, and they may have a tough woody core which may
need to be removed. Full maturity is reached in about 100 to 120 days after
sowing. To harvest a good crop in heavy soil, a light irrigation will help.
Yield
4500 to 5500 kgs /acre of good carrot crop
Storage
Store carrots with the green tops trimmed. Although the tops are edible, during
storage this greenery robs the carrot of moisture and nutritional value. Carrots will
keep for several weeks in the crisper drawer of the refrigerator in perforated plastic
bags. If you plan to use the green tops in soups and stews, store them separately, as
they will only keep for a few days. In very cold regions carrots can be stored in the
ground for a prolonged winter harvest, provided they are protected by a frost cloth or
a thick layer of straw.
Commercial storage
Mature topped carrots can be stored 7 to 9 months at 0 to 1°C, with a very high
relative humidity, 98 to 100 %. However, even under these optimum conditions 10 to
20 % of the carrots may show some decay after 7 months. Under commonly found
commercial conditions (0 to 5°C.) with 90 to 95 % relative humidity, 5 to 6 months
storage is a more realistic expectation.
Glossary
Fanging: Describes carrots that grow with many fork-like legs
Hypocotyl: The region of the stem derived from that part of the embryo between the
cotyledons and the radicle.
Lanceolet : Narrow and tapering at both ends
Mericarp: Any of the one-seeded portions that result from a compound fruit divides at
maturity
Umbrel: Racemose inflorescence that gives the appearance of a umbrella
Review Questions
1. What causes carrots to turn green on the crown (top) of the root?
2. Why do carrots become misshapen, with forked, branched and twisted roots?
3. Which areas in Bhutan are the optimum growing areas for carrots?
4. Illustrate how to prepare and plant a field a carrot plot?
5. What is fanging and how does is this occur?
References
K.G. Shanmuganvelu, 1989. Production Technology of Vegetable Crops. Oxford & IBH Publishing
Co. Pvt. Ltd.
McFarlane, A. (2007). Carrots. [Retrieved, April 008]……
www.annettemcfarlane.com/Stories/Carrots.pdf
Walker, O.P.[Garden: The Medicinal Value. of Fruits and Vegetables [Retrieved, 9th March,
2008]...
www.cofc.edu/~taylord/medicinalvaluesoffruitsandvegetables.pdf