December 2008
Basil
Prepared
by
Can
you imagine a garden without basil? Impossible! Its familiar fragrance,
easy care, and many uses make it indispensable in herb, ornamental, and
container gardens—and, of course, in the kitchen.
A Sense of History
Basil has been known and grown since
ancient times. According to Gerard in his Herbal published in England
in the 1600s, the smell of basil was “good for the heart and for the
head.” The seeds “cureth the infirmities of the heart and taketh away
the sorrow which commeth with melancholy and maketh a man merry and
glad.” Gerard also advised that the juice of the plant was good against
headaches, if it were drunk with wine, and was useful in clearing up
diseases of the eye.
Back in the first century AD, however,
the Greek physician Dioscorides believed basil dulled the sight and
produced “wind.” Others claimed it bred scorpions and that scorpions
would be found beneath a pot where basil grew—a belief that arose,
perhaps, from the prevalence of scorpions in some of the tropical
regions of Asia and Africa, where basil originated, and their
predilection for warm, dark places. Gerard wrote that those who were
stung by a scorpion would feel no pain if they had eaten basil.
Culpepper, a contemporary of Gerard, suggested in his Herbal that basil
would draw out the poison of venomous beasts, wasps or hornets. Today,
herbalists claim it helps to ease flatulence and abdominal pains if
taken as an infusion.
Basil made its way to Europe by the
Middle Ages and to England and America in the mid-17th century, where
it was used mainly medicinally. It was not until the 19th century that
basil became the ever-present component of herb gardens that it is
today. Basil is also very important in Asia and Asian cuisines.
The range of basils available is the
result of the variability of the species, basilicum. The species
contains a natural diversity of fragrances and colors; plant breeders
have selected for and improved on these different traits.
What’s In A Name?
A member of the mint family
(Labiatae), as so many herbs are, basils have the familiar four-sided
stems and whorled flowers of that family; they are not, however, in the
least invasive, as mints can be. The genus name of sweet basil, Ocimum,
is from a Greek verb that means “to be fragrant.” The species name,
basilicum, comes from the Greek basileus, which means “king or prince.”
Basil is often referred to as the “king of herbs,” and no wonder—it is
one of the most useful, and most used, of all herbs.
In frost-free climates, sweet basil
may act as a perennial, but in most areas of the country, it is an
annual, dying at the first touch of frost. There are more than 30
different species of basil, but the most commonly grown are O.
basilicum and its subspecies.
Holy basil, O. sanctum (also known as
O. tenuiflorum) is a sacred herb in India, where it is used in
religious ceremonies and planted around Hindu temples; with its pinkish
purple flowers, it is most often planted as an ornamental.
The four basic types of garden basils
are the familiar sweet green basil, dwarf green basil, purple-leaved
basil, and scented leaf basil. Sweet basil (O. basilicum) grows about 2
feet tall. It has rather large leaves, 2-3 inches long, and produces
white flower spikes. It is the most widely grown. Its “cousins” include
lettuce-leaf and Genovese basils—varieties with much larger leaves—as
well as the spicy Thai basil, ‘Siam Queen’ (1997 All-America Selections
winner), an improved tropical basil with an intense fragrance and
flavor.
Dwarf basil (O. b. ‘Minimum’) is also
known as bush or fine green basil. Its compact growth reaches 10-12
inches high. The leaves are small, about 1/2 inch long, and flowers are
white. ‘Spicy Globe’ and ‘Green Bouquet’ are well-known dwarf types;
the former is aptly named because the plants grow naturally into
rounded, globe shapes.
Purple-leaved basils (O. b.
purpurescens) are very ornamental. ‘Dark Opal’ (1962 All-America
Selections winner), ‘Purple Ruffles’ (1987 AAS winner) and ‘Red Rubin’
(with solid purple leaves, an improved strain of ‘Dark Opal’) are three
of the most popular varieties. These basils tend to have ruffled,
frilled, or deeply cut leaves, which are very pungent; they produce
deep pink to lavender-purple flowers.
Scented-leaf basils bring additional
aromas to the basic clove-anise of sweet basil. Lemon basil (O.
americanum, O. basilicum var. citriodorum) has a very distinct lemon
flavor, especially in the newest ‘Sweet Dani’ (1998 AAS winner). The
leaves are grayish green, the flowers white. The leaves of cinnamon
basil have a spicy cinnamon flavor; flowers are deep pink with purple
bracts. Anise basil has a flavor similar to licorice; its flowers are
slightly purplish.
Growing From Seed
Whether you sow seeds indoors or out,
remember that basil does not like cold, or even cool, weather. Sow the
seeds outdoors when day and night temperatures reach about 55 to 60
degrees. When sown or transplanted at the right time, basil is one of
the easiest herbs to grow successfully.
Starting Basil Indoors
Plan to sow seeds 4 to 6 weeks before
the date of your average last frost in spring. Basils do not need a
long time to grow large enough to transplant to the garden.
* Fill a shallow container, or flat,
or individual 2- to 21/4-inch pots with a commercial seed-starting mix.
Moisten the mix and let it drain.
* Sow the seeds in rows in a flat or
two to three seeds per pot. Cover the seeds with about 1/4 inch of the
mix. Press the mix down lightly and spritz the surface with water to
moisten it and settle the seeds.
* To keep the mix from drying out
while the seeds are germinating, cover the containers with sheets of
clear plastic wrap, or place each in a plastic bag and close it with a
twist-tie.
* Set the containers in a warm
location; the growing medium should be at about 70-75 degrees F (21-23
degrees C). Seedlings will emerge in 4 to 7 days. When they do, remove
the plastic covering and place the containers in bright light or direct
sun in a south-facing window or a fluorescent light garden. Give the
containers a quarter turn every few days so the plants grow straight
instead of leaning towards the light source.
* Keep the mix evenly moist by
watering from the bottom: Set the containers in a sink filled with a
couple of inches of water until beads of moisture appear on the
surface. A liquid fertilizer at one half the recommended rate can be
given to seedlings to promote healthy plants.
* When the seedlings are about 2
inches tall and have at least two pairs of true leaves, transplant
those in flats to individual pots. Thin those started in small pots to
one per pot by snipping off all but the strongest looking one with a
scissors. It is not necessary to transplant purple-leaved basils, such
as ‘Dark Opal’ and ‘Purple Ruffles’, if you sow them about 1/2-1 inch
apart.
* If young plants become tall and
spindly, the growing tip can be pinched to encourage branching and
compact growth. Some of the smaller basils, such as ‘Spicy Globe’, have
a naturally branching habit and do not need to be pinched.
Sowing Directly in the Garden
Sow seeds in the garden when the soil
has warmed up to about 55 to 60 degrees day and night temperatures. Sow
the seeds about 1/2 inch deep in good garden soil; if you cover the
seeds with less soil, they may float to the surface after a heavy rain.
Basil germinates readily, therefore you do not need to sow thickly. You
can sow the seeds in rows or in groups; drop two to three seeds in each
hole for the latter. Keep the seedbed moist until germination occurs.
When the seedlings have at least two pairs of true leaves and are 2 to
3 inches tall, thin them to stand 10 to 30 inches apart, depending on
the species or cultivar. Begin pinching out the growing tips for
compact growth when the seedlings are 3 to 4 inches tall.
To have an uninterrupted supply of
fresh basil, most gardeners sow basil seed several times during the
growing season. The National Garden Bureau recommends sowing basil seed
every 3 to 4 weeks to harvest fresh leaves for culinary uses.
Selecting Bedding Plants
Basil is so popular that you can
readily purchase plants at garden centers or nurseries in addition to
growing it from seed. The plants may be sold in individual pots,
six-packs or flats. Look for young, compact plants. Avoid tall, leggy
plants—even though you can correct their growth habit somewhat by
cutting them back after you have planted them at home.
The leaves of sweet basil should be a
clear deep green; spots on the leaves may indicate they have been
exposed to the cold. Pass up plants that have obvious pests, such as
aphids, on stems or leaves.
If you can’t plant the herbs the day
you bring them home, set them in a protected area away from the drying
effects of direct sun and wind until you can put them in the ground or
in containers.
Out
In The Garden
Select a Site. Basil grows best in a
location that receives full sun—at least six hours (or more) of direct
sun daily. With less sun, the plants have a tendency to get “leggy.”
Plants in containers require the same exposure.
Prepare the Soil. Although herbs are
not very fussy, they do need a light, fertile soil with good drainage.
Amend what you have by digging in about a 2-inch layer of peat moss and
compost before planting. This is particularly important if your soil is
mostly clay.
Transplant. Choose a cloudy, calm day
or late afternoon to transplant your basils to give them a chance to
settle in before they have to contend with the drying effects of sun
and wind. It is very important to plant at the right time, which means
not too early in the season. The slightest cold will set them back. Set
the plants in the ground at the same depth they were growing in the
pots. If you bought six-packs or flats of basil plants, water them
first; then carefully lift each plant out of its cell or separate them
from each other in the flat, keeping as much soil around the roots as
possible to minimize moisture loss. If they don’t come out easily and
you need to handle the plants, do so by their leaves, not their stems
(plants replace leaves more readily than stems). If you started plants
in peat pots, set the pots below the soil line—they have a tendency to
dry out quickly when exposed to the air.
Space plants 10-12 inches apart; dwarf
basils, 8-10 inches apart; larger basils, such as ‘Sweet Dani’, up to
20 inches apart.
Water the plants immediately after
setting them in the ground.
Garden Uses
Basil is as ornamental as it is
edible. Put it in a traditional herb garden, in the vegetable plot in
the center of a bed of red- and green-leaf lettuces or edging a bed of
tomatoes.
Use both the green- and purple-leaved
varieties in borders; the latter are especially beautiful with
perennials such as coral bells (Heuchera ‘Palace Purple’), Sedum ‘Vera
Jameson’, fountain grass (Pennisetum), dusty miller, and blue Salvia
farinacea. Both combine well with annuals, such as dwarf or
medium-height snapdragons, nicotiana, French marigolds, and petunias.
With its natural round shape, the
dwarf basil ‘Spicy Globe’ makes a wonderful edging for any type of
garden: perennial, rose, or herb.
Try the old-fashioned technique of
keeping flies away by planting basils around a patio or in containers
on a deck.
Taking
Care of Basil
Like most herbs, basils do not require
much maintenance. In sandy or infertile soil, fertilize basil plants
for continuous growth. If you amended the soil with organic matter, you
may not need to fertilize basil. Basil plants need about an inch of
water a week. Water, if rain does not provide for the plant’s needs.
Although the flower spikes are
attractive, it is recommended to cut them off as they deplete the
plants’ energy resulting in fewer leaves.
The leaves have the best flavor—the
most essential oils—when they are harvested before the plants flower.
Cut whole stems rather than individual leaves, especially if you want
to use the leaves as a garnish because they bruise easily. Cutting
whole stems is a tasty way of creating a bushy, compact plant: Cut just
above a pair of lower leaves; the plant will produce new shoots at that
point.
Growing in Containers
Basils are excellent herbs to grow in
containers because they add such attractive colors and textures to the
plantings. They look good in pots or window boxes in full sun. A
container of basil by the back door or on a deck provides easy access
for harvesting!
The container should have drainage
holes in the bottom or sides. Fill it with a soilless mix, which is
more lightweight than garden soil and is also free of diseases and weed
seeds. It is easy to provide nutrients all season by incorporating a
controlled-release fertilizer in the mix before planting.
With mixed plantings, place most
basils near the center of containers or at the ends of window boxes.
Use dwarf basils to edge a container planting or on their own in
smaller, 8-inch pots, and place the pots around a larger planter,
marching up steps, or along a walk. Basils combine well with other
herbs and with annuals.
Plant basils at the same level as, or
just slightly deeper than, they were growing in their original pots.
Water the container well after planting. Keep the plants evenly moist
through the growing season; the roots of any plants in a container
cannot reach down or out in search of available moisture. Smaller
containers will require more frequent watering than large ones. If you
plant in a window box, remember that overhanging eaves may prevent rain
from reaching the plants.
From Garden to Kitchen
Basil complements many kinds of dishes
and combines well with other herbs, whether used fresh or dried. The
flavor and appearance of the leaves are best fresh. Many gardeners are
unable to eat their fresh, homegrown tomatoes without fresh basil and a
dash of premium olive oil. Freshly harvested basil leaves added to
mesclun or lettuce salads liven up the flavors. Pesto is another
favorite use for basil. Create the classic pesto sauce, a combination
of basil, garlic, olive oil, pine nuts, and freshly grated Parmesan
cheese.
Whip up basil butter. Cream together
one stick of unsalted butter and 1-3 tablespoons of dried, crushed
basil or 2-6 tablespoons of fresh, minced basil. Place in a covered
container or roll into a cylinder-shape and refrigerate for at least an
hour before using.
Make basil vinegar to use in salad
dressings. Heat vinegar (any type) in an enamel pan; pour it into a
bottle and add several sprigs of basil. Let set for 2 weeks before
using.
If you have any basil left at the end
of the growing season consider drying the leaves. To dry basil, cut the
entire plant and hang on a string in a well ventilated room. When dry,
just pluck the leaves from the stems and store in airtight jars out of
direct light.
Windowsill Plants
It is easy to bring container-grown
plants inside, but you can also pot up a few plants from the garden.
Cut them back rather severely—to about 3-4 inches tall—so they will put
out new growth when they become acclimated to the indoor environment.
Grow them on the sunniest windowsill
you have, preferably with a southern exposure, or put them in a
light-garden. Keep the soil evenly moist and fertilize them once a
month.
Because basils are so easy to grow
from seed, however, the National Garden Bureau recommends it is just as
simple to sow fresh seed indoors at the end of the outdoor growing
season. Pot the seedlings into individual 4- to 6-inch containers and
enjoy fresh basil all winter harvested from your windowsill.
Pests
and Diseases
You may find a few aphids or Japanese
beetles that like your basil as much as you do. To circumvent aphids,
wash them off the plants with a strong spray of water from the garden
hose. Pick or knock Japanese beetles off into a jar of soapy water and
discard.
Fusarium wilt is a soil-borne fungus
that causes yellowing of foliage, discoloration of the stems, reduced
height and eventual wilting of the entire plant. If you plant basil in
the same garden place year after year this could be a problem. Seed
companies have addressed this problem by selling Fusarium free seed. Be
sure to check the seed packet for Fusarium tested seed. The best cure
is prevention. Because it can overwinter in the soil, don’t plant basil
in the same location every year. Avoid excessive watering and provide
proper drainage that will reduce the spread of Fusarium wilt. The only
variety resistant to Fusarium wilt is ‘Nufar.’ Researchers are working
towards breeding Fusarium resistance into many of the common basil
varieties on the market.
The South
Carolina
Nursery and Landscape Association has many experts who can assist
you. A list of
these individuals who
reside
nearest to you can be found in the membership
section on this web site. You may also view past articles here.