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By Skip Richter
Contributing Writer
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Seeds are incredible things!
Those tiny dry bits of organic matter cast from the
plant seem lifeless and insignificant. Yet seeds are far
from lifeless and are the most significant part of a
plant. Examine a typical seed packet. The front displays
a photo promising beautiful, bountiful results. The back
offers instructions to guide us toward achieving this
promise. Inside, the contents resemble small pebbles or
bits of organic debris. Yet in each one a harvest lays
waiting.
You’ve probably heard the old adage, “Man can count the
seeds in an apple but only God can count the apples in a
seed.” A single seed holds the potential for years of
harvests of innumerable flowers and fruit.
I love the winter planting season. Cold, wet weather
conditions limit outdoor gardening activities so I head
out to the greenhouse to begin my spring garden. Out of
the freezer come the various seeds I’ve collected and
stored from the past year: a wildflower that looked
different in color and plant form than the ones around
it, some squash that grew in a mixed planting (who knows
what might come of this!), seeds from a friend’s flower
garden, and the reseeding lettuce a gardener shared with
me a few years back that I still grow each year.
I also have numerous seed packets ordered from various
companies, a smorgasbord of vegetables, flowers and
herbs. There are always way more than I have space for,
but I know you can relate, right?
It’s great winter therapy to plant seeds. Despite the
weather outside, seeds promise the arrival of spring,
bountiful vegetables and beautiful flowers. Planting
seeds is an act of faith and a renewal of the hopes and
dreams of any gardener. Seeds look to the future.
Planting a seed sets the stage for a delicious meal or a
beautiful bouquet months from now. I recall a shadowbox
with small, colorful dried zinnias in it when I was a
child. It was a gift from an aunt to my mom years
earlier. Looking at those flowers now I can’t help but
wonder about the day my aunt held the seeds in her
hands. I wonder if she could imagine that years later
they’d still be adorning a home.
You can start vegetables, flowers, ornamental grasses,
woody ornamentals or even fruit and nut trees from seed
if you provide a few simple conditions for their
success. The following are a handful of common questions
that cover some of the important factors in success with
seeds:
What types of plants can and can’t be grown from seed?
Almost any plants can be grown from seed although some
types are very difficult, with complex and exacting
germination requirements. Some plants seldom produce
seed and others fail to produce viable seed.
Many fruit trees are propagated by grafting, budding or
from cuttings in order to get a genetic duplicate of the
desired variety. If you plant these fruit trees from
seed they will end up being similar in some ways to the
“mother plants,” but not identical. For proof, take a
look at your children or your parents. See what I mean?
While such fruit plants can be grown from seed it takes
many years for the seedling to reach a mature, bearing
age.
Hybrid cultivars won’t produce plants true to the parent
plant. If you wish to save seed, choose cultivars that
are open pollinated, as opposed to hybrids.
What is the best temperature for starting seeds?
That depends on the type of seed you are planting. As a
general guide 70-75 degrees is good for many types of
seeds. Some prefer cooler temperatures and others prefer
warmer. Some are forgiving of a fairly wide range in
temperatures and others are more exacting.
While each species has a minimum and a maximum
temperature for germination, each also has an optimum
temperature for fastest germination. Tomato seeds, for
example, will germinate from a minimum 50°F to a maximum
of 95°F, but the optimum temperature is about 80°F.
Check the seed packet or an online reference on seed
germination to determine the best temperature for the
seeds you want to start.
A warming mat beneath seeding trays will provide a fast
boost for seeds started in cooler areas such as an
unheated greenhouse.
What is the best growing medium?
Most garden seeds germinate best in a loose growing
medium composed of equal parts peat moss to hold
moisture and either perlite or vermiculite to provide
improved aeration and drainage. There are special seed
starting mixes available which are finely ground, making
it easy to plant small seeds at a consistent depth. Use
fresh seed starting mix to avoid some of the common
disease problems which can devastate the tender
seedlings.
When starting seeds of woody plants I use a mix of 50
percent screened compost and 50 percent soil from the
site where the plants will be growing.
How deep do I plant the seed?
As a general rule of thumb, plant a seed at a depth of
about 2-3 times its width. That said, some seeds need
light to germinate. A few examples include echinacea,
ageratum, petunia, coleus, Salvia splendens and
nicotiana. These seeds should be scattered on the
surface and gently pressed into contact with the growing
mix. Check the seed packet for planting depth and
whether the seed should be buried or left on or near the
surface.
A tip for planting small seeds at a proper depth is to
press them onto the soil surface and then sprinkle a
very thin layer of fine grade horticultural vermiculite
or seed starting mix over the top of them. This makes it
easy to barely cover the seeds.
How do I water the seedlings properly?
Start by wetting the seed starting medium prior to
planting. If the mix is dry it may initially repel water
so moistening before planting is important. After
planting, use a mister nozzle to gently wet the planted
seeds. Other types of nozzles tend to blast the seeds
out of the mix with either strong streams or large
droplets.
An alternative is to set the planted trays into a tray
of water and allow the moisture to wick up into the mix.
Then remove the tray and allow it to drain out all
excess water. The idea is to keep the seeds evenly
moist, not soggy wet, until they germinate. I like to
place the moistened tray into a large clear plastic
trash bag or dry cleaner’s bag and fold the end over to
hold in moisture.
I put something in the trays to hold the plastic off of
the soil surface such as a plant label or a piece of
coat hanger bent into a hoop. This creates a moist
chamber ideal for germination that generally won’t
require rewetting until the seedlings are up. Special
seeding trays with clear plastic covers are available at
garden centers. They work great! Once seedlings emerge,
remove the plastic bag or clear plastic tray cover. Then
water as needed to maintain even moisture.
When a seed starts to absorb moisture a complex chemical
reaction begins that eventually leads to the emergence
of a root and a shoot. Once started, the seed is no
longer a tough dry storage container with a dormant
embryo, but is a very fragile new emerging life. If the
seed dries out even briefly once the germination process
begins, it will die. If kept too soggy wet, it will
often succumb to root and stem rot diseases.
How much light do seedlings need?
Seedlings require bright light to grow stocky and
healthy. Sunlight is best but direct sun is not
required. If you can’t give them sunlight, provide very
bright fluorescent light. I use two 4-foot shop fixtures
each with one cool white and one warm white fluorescent
tube. These are suspended over the seedlings and raised
2 to 4 inches above the growing seedlings by chains that
allow me to adjust their height as the seedlings grow. A
plug-in timer set to run 14 to 16 hours a day provides
adequate light for the growing seedlings.
Do I need to fertilize the seedlings?
The germinating seed doesn’t need fertilizing but the
growing seedlings do. Once the seedlings get their first
true leaf (the “seed leaves” that emerge from the soil
first don’t count), begin to fertilize them with a very
dilute soluble plant food at the low “constant feed”
label rate or a seaweed and fish emulsion solution.
Avoid excessive fertilization as this will contribute to
the excessive, lanky growth that results in weak
transplants.
What about seeds that require special pre-treatments?
Some seeds require cold, moist conditions for a period
of time prior to germination. Many of our deciduous
landscape ornamentals, fruit trees and shade trees are
among these plants. Once again, a good reference book or
Web site can tell you which species have such
requirements. Place these seeds in moist sand in the
refrigerator and leave them there for a couple of
months. Then remove the seeds and plant them.
An alternative to this process is to plant them outdoors
in the fall and allow winter rains and cold weather to
prepare the seeds for germination. Cover the containers
with a piece of hardware cloth to prevent marauding
squirrels from digging in the pots and spoiling your
plans!
Other seeds have hard or impervious seed coats that slow
the movement of moisture into the seed to initiate the
germination process. Bluebonnets and Texas mountain
laurel are examples of seed with hard coats. This is
nature’s way of making sure all the seed doesn’t sprout
in one season. There are several methods of scarifying
these seed coats to weaken them and to speed
germination, including nicking with a file, sanding the
edges and even using a sulfuric acid solution for a
specified period to damage the seed coat.
How do I prepare my seedlings for transplanting?
When it is nearing time to plant the seedlings outdoors,
gradually acclimate your seedlings to outdoor
conditions. A sudden move from their warm, luxurious
life indoors to the garden where nighttime temperatures
can still drop into the 40s will shock the plants and
slow growth to a standstill. Move them outdoors during
the day to a very bright spot in the shade and bring
them in at night. Over a period of a week or two,
gradually move them into more direct sun and leave them
out longer to acclimate them to the cool evening
temperatures.
Don’t let the winter weather get you down. Gather some
seeds, growing mix and planting trays and head to the
greenhouse or make room for planting at an indoor table.
Imagine your best garden ever as you start your spring
garden indoors. It’s all there in the seeds!
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