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Table of Contents
Why Start Your Own Plants from
Seed?
It's fun. It's easy. And there are lots of
advantages over buying plants from your local greenhouse.
- Inexpensive. Depending upon what type of plants
you're growing, a packet of seeds usually costs $1 to $2,
and enables you to grow from 15 to 100 seedlings.
- Broader Selection. You have many more varieties to
choose from, including both heirloom varieties and new
hybrids that are genetically bred to be disease
resistant. Most of these special plant varieties are not
available at your local nursery.
- Higher Quality Plants. Your seedlings will thrive on
your individual attention and tender loving care. With a
healthier, stronger start, they will yield more flowers
and fruit with fewer problems.
- Timed to Fit Your Schedule. Rather than depending on
what's available at your local greenhouse, you can start
your own plants from seed at almost any time of the year.
Start your seedlings extra early to get the first flowers
weeks earlier than would otherwise be possible. Stagger
your plantings so you always have a fresh window box
display in summer.
- Beyond all these great reasons for starting your own
seedlings, you can enjoy the simple satisfaction of
nurturing your plants from tiny seedlings into beautiful
and productive plants.
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Step-By-Step Seed Starting
Here are some things you will need:
Click on the seed packet below for a short video
(Black and white QuickTime movie: 913K)
Here are some things you will need to know:
- Plan ahead
Mail-order seed catalogs give you ideas, information
and lots of pretty pictures. They also provide important
background information on each seed. Look for varieties
that are rated hardy for your growing zone and those that
are appropriate for your growing conditions.
If you're a beginning gardener, the place to start is
with easy seeds that are quick to germinate, and don't
require a lot of extra fuss. It's easy to get carried
away and order too many different seed packets
(especially when you are ordering in the middle of
winter). If you are starting seeds for the first time,
you should probably limit yourself to starting no more
than 10 different types of seedlings. Some easy to grow
plants are:
- Marigolds
- Pansies
- Sunflowers
- Kale
- Petunias
- Impatiens
-
- Containers
You can start your seeds in almost any container as
long as it is at least 2-3" deep and has drainage holes.
You can use recycled egg cartons or milk cartons to start
seeds. There are lots of different seed containers on the
market, including peat flats, jiffy pellets, flats with
individual growing cells, and self-watering seed trays.
You may want to start with small containers and then
transfer to 4" or 6" plastic pots, milk cartons, or
homemade paper pots.
- Soil
Seedlings thrive in a moist spongy growing medium.
Soil-less mediums are better than garden or potting soil
because they retain moisture, provide good aeration, and
reduce pest and disease problems. You can purchase a
ready-mixed blend, or mix your own special blend using
equal parts of vermiculite, sphagnum moss, and
perlite.
- Windows and grow lights
Most seeds don't require light for germination, but
you will need to provide a source of bright light as soon
as they germinate. One of the most common mistakes is
relying on sunlight from an east, west, or north window.
In late winter, the amount of light (both in intensity
and duration) coming through these windows is inadequate
for seedlings. A window with a southern exposure is best,
but for some types of plants you may still need to
supplement with a fluorescent light.
- Group your seeds
Once you have received your seeds, group the ones with
similar temperature needs together. Also group by length
of time to germination and weeks to transplant
size.
- Timing
Plants grow at different rates, so timing is very
important. Some seeds need to be started as much as 12
weeks before they are transplanted into the garden.
Others need only 3 or 4 weeks. Make a weekly schedule
before you start planting. In general, seeds are started
anywhere from 3 to 8 weeks before the last frost date in
your area (call your local extension agent if you're not
sure of this date). You can find the timing
recommendations on the seed packet.
If you are using a greenhouse or a very warm growing
room, you should start your seeds a week or two later
than what's recommended on the seed packet. Heat promotes
faster growth and you may find yourself with giant plants
waiting to be transplanted much sooner than you wanted.
Special self-watering systems can hasten growth, so you
may sow seeds a little later than recommended if you use
these.
Your growing space is another consideration. If you
start your seeds extra early, you will need to transplant
them into larger pots after 3-4 weeks. Otherwise, the
plants will become weak and floppy with entangled roots.
Larger pots will take up more space than seedling flats,
so you'll have to plan for the extra window or light
space. The alternative is to sow individual seeds into
large pots to begin with, delay seed starting and
transplant very small plants directly into the
garden.
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Plant Your Seeds
You're now ready to sow your seeds. Look one more time at
the seed packet for planting depth. Some seeds like petunias
are so tiny they should be scattered on top of the soil and
left uncovered, while some seeds like snapdragons actually
require exposure to light to germinate. Most seeds should be
lightly covered with soil. The general rule of thumb is to
plant seeds at a depth that is 3 times their size.
Lightly moisten your growing medium with warm water
before placing it in the containers. Fill your flats or
containers, and tamp down to compact. You can scatter many
seeds in each container or place one or two seeds into each
growing cell. Cover with the recommended amount of growing
medium. Label each flat, row, or container with a wood or
plastic marker so that you can identify them later.
- Temperature
When seed packets talk about temperature requirements,
they are talking about soil temperatures, not the
temperature of the air. You can buy special heat mats,
but usually a warm place, like on the top of a
refrigerator will provide sufficient heat. After
germination, most seedlings grow better at cooler air and
soil temperatures. If too warm (over 75 degrees), the
seedlings will grow too fast and get weak and leggy. Most
seedlings will grow fine at air temperatures as low as 50
degrees as long as the soil temperature is maintained at
about 65 to 70 degrees. You can do this with a heat mat,
and a soil thermometer can be used to periodically check
the soil temperature if desired.
- Moisture
Consistent moisture is required for germination. It's
important to keep the soil moist but not soggy. There are
different ways to achieve this. Some gardeners cover
their flats with clear plastic until the seeds germinate
to help retain moisture. Some self-watering seed-starting
systems employ a special capillary matting and a clear
plastic cover to ensure consistent moisture. Once seeds
have sprouted, remove any plastic covering to reduce the
moisture and humidity levels.
Check soil moisture every day. Again, the soil should
be moist, not wet. You may need to water every day, or go
2 or 3 days between waterings. This depends on the type
of container you're growing in, air temperature, and the
humidity of your home.
- Light
Once your seeds have germinated, they'll need to be
placed in a south window or under lights immediately.
Check your seeds daily! Seeds that germinate and start to
grow without adequate light will become tall and leggy--a
condition that's hard to correct.
Most seedlings require 12-14 hours of direct light in
order to manufacture enough food for healthy stems and
leaves. The characteristic legginess one sees in a
windowsill planter, indicates the plants are not
receiving enough intensity or enough hours of light. If
you are growing in a south-facing window, you can enhance
incoming light by covering a piece of cardboard with
aluminum foil and placing it in back of the containers.
(The light bounces off the foil and back onto the
seedlings.)
If you don't have a south window, you'll need to
supplement with grow lights. When growing seedlings under
lights, you should use a combination of cool and warm
fluorescents or special broad spectrum influorescent grow
lights. Incandescent bulbs produce too much heat in
relation to the light given off, and the light lacks the
"blue spectrum" needed to keep plants stocky. Because
plants need high light intensity, you should keep the
bulbs very close to the plants - no more than 3" away
from the foliage. The bulbs should be left on for 12-14
hours per day if you have no other light source. If
you're growing in a window, you could turn on the lights
around 4:00 pm to add an additional 4 hours of quality
light.
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Caring for Seedlings
When your plants are up and growing, you may need to do
some thinning. If you have planted several seeds in each
container, you can do one of two things. Some gardeners
can't bear to part with even one seedling, so they prick out
the extra seedlings and very carefully plant each into a
separate container. Or you can eliminate the extra seedlings
and keep the most vigorous one in each container. You can
snip off the extra seedlings with your fingernail or sharp
scissors.
- Fertilizing
Once your seedlings have developed their first "true
leaves", it's time to start feeding them (the first 2
leaves are called "cotyledons". The second 2 leaves are
the "true" leaves.) Because seedlings are tender, they
don't need a full dose of fertilizer. Baby them by
watering once a week with a fertilizer mixed to half
strength. Continue this dilute feeding for several weeks
before starting with a full-strength fertilizer.
- Transplanting
You may need to transplant your seedlings into larger
pots if they start to get crowded and it's still too
early to put them outdoors. Don't wait until the plants
are a tangle of foliage and roots. The less you rip and
tear the roots, the better your plants will survive the
move.
Carefully dig around the seedling with an old spoon or
your fingers. Some growing cells can be popped right out
of the growing flat intact. Place the seedling into a
larger pot filled with transplant mix or potting soil and
water well. Return them to the grow light or
window.
- Hardening off
Once the weather has warmed up, it's important to
"harden off" your plants by gradually exposing them to
the outdoor weather. Your seedlings have been pampered
with warm temperatures, light and water. The weather
outside is not so kind, especially in the spring! A week
before you transplant outside, reduce watering and stop
fertilizing. Place the plants outside for one hour each
day, on a protected porch or in the shade of a tree.
Bring them inside each night. Repeat each day, gradually
increasing the amount of time they are exposed to the
outdoors. Avoid wind and hot sun.
- Planting
After they are hardened off, your seedlings are ready
to be planted into their summer locations out-of-doors.
Choose a cloudy day or the evening of a sunny day. This
will decrease the shock and give your plants a chance to
adjust. Water well when planted and for the first several
weeks, and once a week thereafter, unless sufficient rain
has fallen.
- Enjoy your bounty of beautiful flowers.
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Troubleshooting: Common questions
about seed starting.
Q. Only 1/4 of my seeds germinated. What went
wrong?
A. A number of factors affect seed germination. Check the
seed packet to determine if all the requirements for
temperature and light were met. If the soil was cold and
excessively wet, the seeds may have rotted. Dig up one of
the seeds and examine it. If it is swollen and soft, the
seed has rotted and you'll need to start over. If the soil
was too dry, the seeds may not have germinated or may have
sprouted and then dried up.
Q. My seedlings are spindly. What can I do?
A. Plants grow tall and leggy when there's insufficient
light. Use grow lights as recommended in our section on
lighting. You can also lower the temperature in the room and
reduce the fertilizer to slow the plants' growth.
Q. The leaves on my tomatoes are starting to look purple
along the veins and on the underside of the leaves. What's
happening?
A. Purple leaves are an indication the plant is not
receiving enough phosphorus. If you have been using a dilute
fertilizer for the first 3-4 weeks of the seedlings life, it
may be time to increase the fertilizer to full strength. The
phosphorus content (the middle number on the fertilizer
analysis) should be at least a 3.
Q. My seedlings were growing well until all of a sudden
they toppled over at the base.
A. When seedlings become discolored on the lower stem and
topple over, they've probably been killed by a soil borne
fungus-a condition known as "damping off." It is difficult
to eradicate once it's present in the soil. You can avoid
the fungus by using a sterile, soil less growing medium, and
keeping your growing containers in a room where there's good
air circulation. Soil that's too wet or too cold is also
susceptible to damping off. If you see signs of this fungus,
transplant the healthy plants out of the container, and
compost or throw away the diseased plants and soil.
Q. I've got mold growing on the top of the soil. It
doesn't appear to be hurting my plants, but should I be
concerned?
A. Mold is an indication that the soil or growing medium
is too wet. Withhold water for a few days and try to
increase the air circulation around the containers by adding
a small fan or opening a door. The mold won't harm your
plants as long as you can improve the growing conditions
right away. You can also scrape some of the mold off or try
transplanting into fresh growing medium.
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Information adapted from a bulletin published by the:
Gardener's Supply Company,
128 Intervale Road, Burlington, Vermont 05401
1/800/863-1700.
For other links to garden seed and supply catalogs, see my Garden
Sources.
Animated gifs are from The
Ultimate Animated Gif Site.
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