Indoors Seedling Planting, Germination, and Care
Mother Nature has her own way of germinating seeds. In the field, she provides
warmth from the sun, moisture from the clouds, and nutrients in the soil.
Mother Nature also has a way of disappointing us from time to time, by either
not bringing one of the essential ingredients, or bringing too much all at
Some seeds are best planted directly into the garden. Some plants are better
of, if they get a healthy head start indoors. The length of growing time
in your area may be shorter than the time the plant needs to bear fruit or
to flower, making an indoor start a necessity.
The steps below will ensure and maximize successful indoors planting and
Why Start Plants Indoors:
Many flowers and vegetables are started indoors. But, do you know the reasons
and benefits that will help you determine which plants to start indoors?
First, the growing season in many areas is shorter than the time the plant
needs to produce flowers or fruit. Indoor planting allows many gardeners
to grow plants and varieties that are not native to their area.
Extending the harvest is another major reason why gardeners start plants
indoors. Many flowers and vegetables produce weeks earlier, if started indoors.
Marigolds for example, benefit by flowering earlier than if direct sowed.
They will continue to produce flowers right up to the first frost.
Everyone wants that first tomato or cucumber of the season. It tastes so
delicious, and we can hardly wait. And, there is friendly neighborhood pride
and bragging rights, associated with being the first to produce home grown
tomatoes for the season.
Healthier seedlings become stronger and better plants. Give a seedling a
healthy start, and it will pay you dividends all season long. That healthy
start often comes from a properly controlled, indoor environment.
Simply because it's fun. Like any hobby, gardeners really enjoy every aspect
gardening. There's a challenge to growing difficult to start petunias
or peppers, and putting out a seedling that is better than you can find in
any gardening store. It also extends the hobby into those late winter and
early spring months, when most gardeners are chomping at the bit to get some
dirt under their fingernails.
When to Start Indoors:
The general rule of thumb, is to start transplants indoors six to eight weeks
before the last frost date for your area. Some plants, such as peppers and
petunias, require even more time. Other plants, like the cabbage family and
head lettuce, require less. Some people make a series of plantings, especially
for lettuces and cabbages, to create succession plantings and to extend the
harvest. Ten heads of lettuce in two weeks is just too much for most families.
But, a couple heads a week is just right.
Gardening Tip: Check the instructions on the back of the seed packet.
It usually provides a recommendation of indoor planting times, and "days
to germination". Experience will help you to fine tune when to start them.
Sprouting seeds indoors is quicker and more successful, when using a heated
Planting and Seedling Germination:
The basic steps of indoor seed starting and germination are:
Viable seeds - Good seeds that are not hollow, and are not so old that
germination rates are poor. Some seed can remain viable for years, if stored
properly. Others normally last only a season in storage.
Soil - Use a good, seed starting mixture, that is light and sterilized.
Water - The soil should be moist, but not soaked.
Warmth - Growers can easily increase their success by providing the ideal
temperature for germination. The ideal seed starting temperatures vary by
type of seed. Most are between 70 to 85 degrees Fahrenheit. Some seeds, like
peas and early season vegetables, will germinate at a lower soil temperatures,
even as low as fifties. Sprouting seeds for other garden plants, like pumpkins
and peppers, requires temperatures on the higher end to induce them to sprout.
Seeds can be germinated outside of their ideal range, but the further away
from the ideal range for the particular seed, the lower the germination rate.
Garden Tips: Test your seed for viability in advance, especially if
you have saved seed from last year. Plant a few seeds well before the normal
planting time. Count the number you planted and the number that germinate.
The resulting percentage is your expected germination rate.
More on seed germination tests.
Here is our recommended step by step instructions to maximize germination:
Purchase sterilized seed starting mixture. This is a light weight medium
that has all the nutrients your seed needs at birth. Experienced growers
often create their own starting mix, or amend store bought soil. This is
part of the fun of planting for experienced garden hobbyists. Tip for new
gardeners: Stick with the seed starting mix until you gain some experience
Select the right containers. So what's the big deal? If you select a container
that is too small, your seedling can outgrow it's home before you are ready
to transplant. A root bound seedling does not translate into maximum growth.
Large paper mache or peat pots promote more open development of roots, but
separating individual plants later, can result in tearing of roots and increased
transplant shock. Using the individualized seed pots and trays helps to minimize
Fill the containers with the seed starting mix and water thoroughly. Make
sure the soil is wet, but not soaking.
Plant the seeds. Another seemingly easy step. But, new gardeners have a habit
of planting seeds too deep. We recommend planting seeds a little less than
the recommended depth. You can carefully add soil around the seedlings at
a later point if needed.
Provide bottom warmth to the seeds. Some people use a heating mat, while
others put them on top of a warm oven, by the fireplace, or in a sunny window,
skipping the expense of a heating mat or other devices.
Creating a seed incubator is also popular. Create a wooden or plastic enclosure
large enough to hold the containers you are using. Put a light inside the
enclosure. The heat from the light will raise the temperature and create
a greenhouse effect. It is important to measure the temperature to make sure
it does not get too warm. Temperature vary depending upon room temperature,
wattage of light bulb and size for the enclosure.
Now the wait begins! The time required to germinate may be a few days to
a few weeks. For seeds with a long germination period, we recommend you plant
in smaller groups over a couple of weeks. This way if the first group does
not germinate, you won't be waiting three weeks to find out.
Seedling Care and Nurturing:
As your seedling emerges from the soil, most growers breath a big sigh of
relief. Close your eyes, and you can almost see the plant grow and flourish
into it's full beauty, producing an enviable profusion of flowers or vegetables.
As you open your eyes, you will immediately begin a new set of worries,
over-nurturing the newborn seedlings indoors for a short time while the outdoor
weather catches up with your dreams.
Thin Seedlings as needed- - Plants in your garden do not like to be
crowded. Ditto with your seedlings, who need all the sun and nutrients that
they can get. You may want to leave a few extras for a while, as mortality
rate of seedlings can be high.
Let there be light, and plenty of it- - As soon as the newborn seedling
begins to emerge, it seeks light. Newborn seedlings require as much light,
and as direct a light source, as possible. Placing the plants by a window
with a southern exposure is the first step. This alone may not prove to be
enough, for the seedling to grow healthy and strong. First, the sun is not
up as long in the spring as it is in the summer. Second, there are many rainy
spring days with little or no direct sun. You should also acquire an artificial
Grow Light. Place the seedlings under it, on cloudy days and at night.
Let There be Water, in just the right amount- - Provide water to your
seedling every couple of days. Do not soak the soil each night. Overly wet
soil encourages the development of damping off disease. Let the soil dry
out a little on the top, then water thoroughly. Watering from the bottom
is preferred. For seed trays, add water to the bottom of the tray . The soil
will absorb it through the bottom holes in your container...your container
does have holes in the bottom, doesn't it!?!
Feed me, feed me- - The seedling does not need a lot of extra nutrients
in it's first few days of life. Your soil starting mix usually comes with
a balanced formula of nutrients that the seedlings need. After several days,
adding a little liquid fertilizer to the water is helpful, but you do not
need to give it full strength.
If the roots begin to come out the bottom of the pot, it is time to plant
your seedling outdoors, weather permitting. If it is still too cool, keep
the bottom of the tray moist, or put some extra soil in the bottom of the
tray. Or, transplant seedlings to a larger pot. Most plants do not like to
be root bound.
to transplant seedlings outdoors.
Guard against Leggy Plants- - Seedlings are leggy, when their main
stem or stalk grows tall and thin, and can hardly support the leaf structure.
It is caused by insufficient sunlight and a sheltered environment. Indoors,
they do not experience the effect of wind, and do not need to develop structure
to defend against it. Most seedlings do not even experience a slight breeze.
When transplanted outdoors, "leggy" plants can be damaged or broken by the
Garden Tips: Take your hand, or a couple sheets of newspaper and fan
the plants a few times a day. You can even lightly brush the tops of the
plants, brushing back and forth in varying directions. You may notice the
plant growth seems to slow down for a period. What they are really doing,
is building a stronger stem or stalk.
Let there be no Damping Off Disease:
Those of us who have grown seedling indoors for any number of years,
know what "Damping Off" disease. This is a white mold that forms in the top
of the soil. Damping Off Disease flourishes in cold, wet damp weather along
with little sunshine. It quickly spreads across the soil and wilts the seedling.
Take it's habitat away, and the disease can not survive. Plants on the other
hand, love just the opposite conditions. The more you make conditions ideal
for your plants, the more likely you will avoid Damping Off Disease and other
mold and fungal problems.
If you do experience problems, do not give up hope. Here are some things
you can do to minimize or eliminate disease problems:
First, get the plant in direct sunlight if at all possible.
Allow the surface of the soil to dry out, in between watering.
Water only from the bottom.
If you see a white or gray mold, scrape as much of the mold off the soil
Stir the top of the soil without disturbing the roots. It will also speed
Add some soil, although this may or may not produce results.
Increase room air circulation. You can gently blow air on your plant trays
with a small fan.
Avoid sowing your seeds in the basement and leaving them there for a couple
of days. While the trays are conveniently out of the way, this is a perfect
breeding ground for Damping Off Disease.
More on Damping Off Disease