Growing seedlings inside is a combination balancing act and race against
time. Nevertheless, it's one of my favorite indoor sports.
I'm going to assume you're growing annuals, or perennials that require
no special prechilling treatments.
And these are my methods of doing things... other gardeners have
equally good methods that work for them.
Problem #1: Seeds have to be moist enough to germinate, dry enough
that the fungi don't move in, in soil damp enough to keep them going,
but with enough air spaces that oxygen can get to the seeds and
General solution: a well-drained potting soil, and plastic pots
with good drainage holes. Keep soil about as moist as a sponge you'd
use to wipe off the kitchen counter.
Problem #2: Drought and drown. Most of us don't have the time
to watch seedlings really, really carefully and water them every
time they need it. Plus some of us (ahem! who me?) have minds
like sieves and just plain forget to water now and then. A
seed that's started to germinate and then dries out is dead.
General solution: Keep the humidity up so the soil doesn't dry
out so rapidly. If you've got seeds in soil, cover with
plastic wrap so the tray doesn't dry out. Once you see the
first signs of seedlings, though, you need to remove the cover
and start paying closer attention.
Problem #3: The seedlings come up, they look wonderful, and
then start flopping over, with a pinched stem at the soil line,
just like a tiny lumberjack has been clearcutting. It's the
dreaded "damping off" group of fungal diseases.
General solution: Instead of covering the seeds with soil,
cover them with a thin layer of sand (yep, like you give the
kids for the sandbox) or milled sphagnum moss. Keep the
air circulating, not stagnant, once the seedlings are up
(which, of course, causes some water loss... try a combination
of a humidifier or steamer and a small fan). If you see
damping off, use chamomile tea for watering (haven't tried
this, but some very good gardeners in this group swear by it)
or one of the commercial fungicides made for this purpose.
Personally, I haven't needed to resort to either remedy... I
find sand or sphagnum plus good air circulation is plenty
Problem #4: watering. The soil is so dry when you put it
in the pots, and then you plant the seeds, and try to water,
and the seeds float right out. Later, the trays are either
floating in water or the top is damp and the bottom soil is
Solutions: Fill the trays with soil, then set them in a shallow
pan of water for several hours, till the soil is moistened all
the way through by capillary action. Let the excess water drain
from the trays for several hours before planting. Plant the
seeds directly on top of the soil, then cover with a bit of
sand or milled sphagnum. Water by misting or by bottom watering
until the seedlings are up.
Problem #5: The packet says they ought to be up in 14 days, and
it's been 3 weeks. Etc.
Solution: germination is also cued by temperature. At the
optimum germination temperature, the time for germination is
minimized. For most of our common garden plants 70-75oF *soil*
temperature during the day, and 65 or so at night is about
ideal. Some plants must have cooler temperatures; others must
have warmer temps (the packets usually have this information).
Folks who keep their house at 65o will generally have soil
temps about 62o if they leave the trays uncovered, and the seedlings
will be slow to germinate, and often more prone to damping
off. While the seeds are germinating, many people find the
top of the refrigerator, the top of the water heater, or
the spare bathroom with the register open and the door closed
gets the soil temp up to the proper levels. Other folks
resort to heating mats of various designs. Be SURE to use
mats (and other electrical equipment) designed for use in wet
places and connected to GFI receptacles. Fried gardener is
not a tasty dish.
Problem #6: How much light? When? How? What if the
packet says germinate in the dark? Aren't you supposed to
start seeds in the dark and put them in the light later?
Solution: think about it. If seeds had to germinate in the
darkness for several days, they sure wouldn't grow outside!
(There are a few wierd plants with this dark/light germination
trigger, like a certain substrain of Grand Rapids lettuce. But
they're rare.) Even seeds in the soil get a significant
amount of light. The red wavelengths that trigger germination
can penetrate 18" of good soil.
Seedlings need light... lots more than most people think...
pretty much from the start. South or west-facing windows
are the old standby, but the windowsill is often too chilly.
Most folks opt for fluorescent lights, usually a 4 ft
shoplight fixture placed about 3" above the tops of the
seedlings (yes, you need to keep raising the light fixtures
as the plants grow.) Lots of light means nice stocky, dark
green plants that grow quickly. No, you don't need expensive
"grolight" tubes. But you do need to replace the tubes
after they've been used for 3-6 months, because the light output
drops greatly. The $0.99 tubes from the discount stores work fine.
18 hours a day for light is plenty. 24 hours a day screws up
the flowering times for some plants.
Problem #7: They're growing! They're growing! Now I've
got to transplant them, don't I? They're too small! I'll
kill them! Can't I just give them more fertilizer instead?
Solution: I sow seeds in rows in my seed trays, trying to
get a single file line of plants. (well, I *try*
. I don't
.) When the seedlings have two true leaves (the
first pair are cotyledons, seed leaves, and then you wait
for two more leaves to appear), they need to be transplanted
to give them room to grow. I use the "pony packs" nurseries
use... I like the size that's about 6 plants per pack. You
can buy whole sheets of these and the trays they fit in.
I take a plant label and scoop down beside a line of seedlings,
lifting a little bunch of them at a time...maybe 6-10.
Carefully separate one from the bunch by holding on to a
the stem!), and shaking a bit, pulling
the bunch apart. Put the seedling down on top of a
compartment of the pony pack (already filled with soil),
and poke the roots down into a premade hole in the soil gently
with a finger or a blunt pencil. Just one poke does it once you
get the rhythm.
As soon as possible (within 30 min or so), water the tray
gently from the top with a very fine spray of tepid water.
Baby bath water temperature is fine. Let the tray drain,
then water again. And again, until you're sure the soil
has settled around the roots and the soil is wetted through.
Return the tray to the same temperature and light the plants
were in before. Be really careful watering for the next
few days until the roots have had a chance to start growing
into the soil, lest you wash out the plants.
Problem #8: How about some fertilizer now? They're
Solution: Greenhouse growers can use fertilizer profitably
on their plants, because their goal is producing blooming
sized plants for the consumer. They can afford the soil
tests that tell them what and how much they need to add.
As a home gardener, I'm trying to produce plants that
will grow well in my garden. I've found that, for most
plants, I'm better off NOT trying to grow them like the
pros do. Instead, if the plants get to the stage where
the roots are pretty well filling their compartment, I
don't fertilize... I transplant. Either to the great outdoors,
or to a little bigger pot. If you do transplant to a
larger pot, choose one that the current roots will take
up at least 1/3 of the volume of the pot. Overpotting is
often a death sentence unless you're really persnickety about
Problem #9: Everything looks great, and I want to plant them
out this weekend.
Solution: Whoops... probably you forgot to start "conditioning"
the plants to the great outdoors a couple of weeks ago. Outdoors
generally has lower humidity, less frequent rainfall and higher
light levels, and if you plant your babies out directly, they
may wilt. Instead, start taking them outside in the shade
for a few hours a day... then letting them have some direct
sunlight for a couple hours a day, shade the rest. Let them
wilt just a tiny, tiny bit while they're outside. Give them
at least 3-4 days of this sort of "abuse" before you plant them
out. This is called "hardening off", and it generally results in
plants that just keep right on growing without breaking stride.
Problem #10: It all grew! I don't have room for it all! I'm
going to be awash in zucchini!
Solution: Don't plant it all. Palm the extra seedlings off
on friends, relatives and neighbors. Put them on the curb with
a "free to good home" sign. But don't crowd up your plantings
just because those seedlings look so small now, and you've got
153 tomato seedlings that you've grown. You'll get better
yields per plant by giving them the room they need to grow,
and besides, who wants to spend all of August canning tomatoes?
Kay Lancaster firstname.lastname@example.org