By Dr. Mercola
If you're growing your own vegetables, now is the right time to start
your lettuce. Lettuce of all kinds thrives in cool temperatures and
consistently moist soil, so spring and fall, when temperatures are
between 45 and 75 F, are the best times to grow them. Popular lettuce
types include:
Loose-leaf varieties — Fast-growing delicate leaves
that grow from a central stalk; cutting the outer leaves rather than
pulling the whole head will allow the plant to keep growing new leaves
to replace what you harvested
Butterhead (Boston) — Soft, tender leaves with white heart; requires cool weather and optimal soil quality to thrive
Mesclun blends — Spicier greens such as radicchio and mustard add flavor and color to your salads
Romaine — Heat-tolerant with crunchy long leaves. Use red or red-speckled varieties to add color to your meal
Crisphead (iceberg) — Heat-hardy with thick, crunchy leaves, high in fiber but low in overall nutrition
When and What to Plant for Spring
First, check your Farmer's Almanac (The Old Farmer's Almanac is now available online1)
to find the last frost date for your local area. Lettuce should be sown
six weeks before the last frost date. Ideal soil temperature is between
55 and 75 F. Within this range, seeds will sprout in two to eight days.
If your seeds resist sprouting, they're probably too old. Lettuce
seed should be replaced annually. Fresh seeds have a germination rate of
about 80 percent, and a single standard seed packet will produce about
80 heads of lettuce.
Make sure your soil is rich in humus and retains moisture well, as
the soil should never be allowed to dry out. Lettuce also needs plenty
of nitrogen. To ensure a continuous spring crop, plant your lettuce as
follows:2,3,4
1. Plant seeds in cold frames six weeks before your last spring frost date. 2. At the same time, start another batch
of seeds indoors under growing lights. When the seedlings are three
weeks old, place them outside for two to three days to adjust before
transplanting them into your planting bed.
For the first few days, use a shade cover to protect the tender
plants from excessive sun and wind exposure. Reducing watering and
exposing the seedlings to lower temperatures for three days before
transplanting them into your garden will toughen them up further. 3. Two weeks before your last spring
frost date, direct seed another batch in your garden. If the weather
threatens to warm up considerably, be sure to use more heat-tolerant
varieties.
Be mindful of the fact that if the soil is too warm, germination may
not occur. You can encourage germination by placing the seeds on wet
blotting paper and refrigerating them for five days before planting
them. 4. As the seedlings begin to grow, you'll
need to thin the lettuce to allow adequate growing room. Begin thinning
when the seedlings have four leaves.
Thin leaf lettuce so the plants are 4 to 6 inches apart; butterheads, 3
to 5 inches; romaine varieties need about 10 to 12 inches; and head
lettuce needs about 12 to 16 inches. Rows should be about 18 inches
apart. 5. Water daily. The soil must not be
allowed to dry out as this will make the leaves thin and bitter. Lettuce
has shallow roots, so the soil surface should be kept moist but not
soggy. Adding a thick layer of mulch will help retain water and cool the
soil. If the weather gets too hot, put up a shade cover.
Fall Crop Growing Tips
For a fall crop, find the date of your first fall frost and start
planting seeds eight weeks before the frost date. Direct seed batches
every one to two weeks for a continuous fall crop. Once you're a month
out from your first frost date, be sure to sow only cold-tolerant
varieties such as the following.5
Alternatively, use a mixed seed packet, which can contain a dozen or more varieties. The hardiest ones will survive.
Green Forest
Hyper Red Wave
Merlot
Midnight Ruffles
New Red Fire
Oscarde
Panisse
Pablo
Red Salad Bowl
Salad Bowl
Winter Marvel (Bibb variety)
Winter Wonderland (Romaine)
Planting and Harvesting Tips
If you're using a planting bed, loosen the top 10 inches of soil and
mix in about an inch's worth of compost. Seeds should be planted at a
depth of about one-fourth inch, with 1 inch between seeds.
If you want, you may simply scatter the seed across your planting
bed, but be sure to thin and transplant the seedlings as they start to
pop up.
Lettuce can also be grown in containers, or you can add them to your
flower beds as edible greenery. Growing several different varieties and
planting a new batch every week or two will provide you with fresh salad
greens for several months out of the year.
Adding compost or fish emulsion once or twice during growing season
will promote speedy growth. If the soil is too dry, the plants can start
seeding early, at which point they tend to get really bitter. Pull and
discard any plant that goes to seed.
If you want to save seeds, save only those from the very last plants
that go to seed, as early seeding is an undesirable trait. To prevent
the seed head from toppling over, you may need to stake the plant. Once
the seed pods are plump, gather them and store in a paper bag in a cool,
dry place.
Harvesting is simple: If you need the whole head, simply cut the head
off near the soil line. Alternatively, just cut some of the mature
leaves from the outside with a pair of scissors, leaving the center in
place. New leaves will continue to fill in.
The best time to harvest is in the morning, after they've had time to
plump up with water overnight. Rinse with cool water and pat dry before
storing in the refrigerator.
Harvesting your lettuce while still immature is a simple way to get
more nutrition out of your lettuce. After about two to three weeks, when
the plants have reached a height of about 2 inches, they're considered
microgreens. At a height of about 4 inches, they're known as "baby
greens."
Both microgreens and baby greens are packed with higher densities of nutrients than full-grown vegetables.
Addressing Pests Without Chemicals
Common pests and ways to address them without toxic pesticides are as follows:
• Slugs — Signs of a
slug problem include smooth-edged holes in the outer leaves. Simple
remedies include collecting them by hand (use gloves), trapping them in
beer traps, or spraying cold coffee on infested plants until you see no
further sign of infestation. When these approaches fail, I have had
great success with Monterey Sluggo, which is OMRI certified for organic
gardens. • Aphids — Aphids are
typically found in the folds between leaves. Simply spraying them off
with cool water can help. Ladybugs and syrphid fly larvae6
(also known as hover flies or flower flies; often mistaken for bees and
wasps) are natural predators that can quickly suppress an aphids
infestation.
You can tell you have active syrphid fly populations in your garden
if you see black oily smears on plant foliage. This is the excrement of
the larvae. If you don't have an active syrphid fly population, you can
buy live ladybugs (available online) and apply them to your garden.7
Before releasing them, refrigerate the live ladybugs for 30 minutes.
It's best to release them in the evening, so be sure to time it
properly. Spray some water on the lower portion of the area infected
with aphids, then sprinkle the chilled ladybugs on the lower half of the
plant. The chilling will slow the ladybug's metabolism, basically
putting them to sleep for the night.
As the sun warms them up in the morning, they'll start scavenging
for food and laying eggs. So, even though many will fly away, the eggs
will hatch larvae that continue feeding on the aphids, and the grown
ladybugs will continue the lifecycle of laying eggs and controlling
pests in your garden. • Cutworms (moth larvae)8 — You
will typically see these caterpillars in your garden in the evening,
after dusk, which is when they start to feed. During daylight hours,
they can be hard to find as they curl up in different hiding spots.
Cutworms can do severe damage, as they chew through the plant's stem at
the very base of the plant. They also feed on plant roots. Usually,
infested plants cannot be salvaged.
To prevent cutworms, place a 4-inch-tall plant collar made from
cardboard around each plant stem. Save and reuse toilet paper tubes for
this purpose. Simply cut the tube in half, lengthwise, and down the
center to slip it around the plant. Another alternative is to pick off
the cutworms by hand. Go out after dark and use a flashlight to find
them.
Place the cutworms in a bucket of soapy water. Repeat every few
nights until the infestation is under control. Other chemical-free
treatment alternatives include the following:
◦ Sprinkle used coffee grounds or ground up egg shells around your plants ◦ Sprinkle diatomaceous earth around each plant ◦ Use oak leaves as mulch around the plants ◦ Plant tansy near cabbages to ward off cutworms ◦ Fireflies are a natural predator to cutworms, so if you have them in your garden, consider yourself lucky
Preventing Plant Disease
While lettuce needs moist soil, poor drainage can lead to soggy soil
that promotes bottom rot and gray mold. As a general guide, only plant
lettuce in the same spot once every three years. This will prevent many
soilborne diseases. To avoid bottom rot, make sure the soil is moist but
well drained. Planting your lettuce on ridges elevated about 4 inches
can be helpful.
Also avoid wetting the leaves when watering. Gently fold the leaves
off to the side with one hand and only water the soil. Gray mold
produces grayish-green or dark brown spots on the leaves. Any infected
plants should be pulled and discarded far from your garden to avoid
spreading.
Regrow Romaine Lettuce in a Bowl of Water
As seen in the video above, regrowing romaine lettuce requires
nothing more than a shallow bowl and some water. Once you've cut off the
leaves, leaving a couple of inches' worth of the head, simply place it
in a bowl with one-half inch of water. Replace the water daily. New
leaves will begin to sprout from the center, eventually regrowing the
entire plant.
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