By the middle of February many gardeners are getting cabin fever
and can’t wait to get outside into their garden. A good way
to get over the winter hump is to start flowers and vegetables from
seed indoors for later transplant. Growing plants from seed is inexpensive,
easy, and efficient. The biggest advantage is a much wider variety
of plants and cultivars are available from seed than from ready
to buy transplants.
Materials needed to begin seeds indoors are not expensive or elaborate.
The minimum supplies required are: clean containers with drainage
holes (pots, flats, peat pots, plastic cups, or the bottom of milk
cartons with drainage holes punched in), clean potting soil or seed
starting mix (do not use garden soil from outdoors), light (either
natural or shoplight with new cool white florescent bulbs), and
Transplants can be successfully grown in the natural light of a
south or west window, but most gardeners prefer using artificial
light to supplement the natural light. Artificial light alone is
also very effective. The key to using artificial light is keeping
the light source within two to four inches of the top of the plant.
As the plants grow, the lights should be raised to maintain the
2 to 4 inch space between the plants and light. Cool white fluorescents
provide adequate light for seedlings and will not get too hot. Make
sure you purchase new fluorescent bulbs each year because fluorescents
dramatically decrease in light output as they age.
Most germinating seeds and young seedlings prefer air and soil
temperatures of 65 to 75 degrees Fahrenheit. The temperature should
be lowered 5 to 10 degrees after the first set of leaves appears.
Reduced temperatures promote shorter stockier plants.
Plants with a long interval between planting and flower or fruit
production, such as impatiens, broccoli, and tomatoes, are ideal
candidates for starting indoors.
Before starting seeds indoors planting date should be calculated
based on optimal transplant time. Figuring the date to start seed
takes a little arithmetic or, for the math impaired, counting weeks
on the calendar.
Base your calculations on the average last spring frost date, which
is April 25 in northern Illinois. [Editor’s note: Be aware
that this date is an average, which means that 50 percent of the
time , the last frost comes after this date. In recent years, it
has been common to have frost even in mid-May. Take this into consideration
when timing planting]. Southern Wisconsin gardeners or Illinois
gardeners in colder pockets should use May 5 as their average frost
date. Cautious gardeners use May 5, so they don’t have to
worry about a late frost. Keep in mind that the plant’s tolerance
to cold temperatures determines transplant date. For example, tomatoes
are damaged by frost and must be transplanted on or after the frost-free
date. In contrast, broccoli are very cold hardy and may be transplanted
outside 4 weeks before the average last frost date.
Check the seed packet or catalog for the recommended sowing time
and transplant time. Starting from the outdoor transplanting date,
count back the number of weeks the plant will need to germinate
and grow to the proper size in order to get the seeds sowing date.
Here’s an example. Tomatoes need five to eight weeks to germinate
and grow to transplant size. Counting back or subtracting seven
weeks from the last frost date of April 25 gives a start date for
tomato seeds of March 5. If you think late April is too early to
put tomatoes outside, then push the seed sowing date back a couple
of weeks to produce May transplants.
Plant the seeds in pre-moistened potting soil at the depth listed
on the seed package or, in lieu of directions, at a depth two times
the seed’s diameter. Because most people have difficulty thinning
out extra plants, the seeds should be spaced an adequate distance
apart to give the seedlings room to grow. (An easy way to thin seedlings
is to cut off the extra plants at the soil line using small scissors.)
Many gardeners cover the newly sown flats or pots with plastic until
the seeds germinate so that moisture is maintained in the potting
Seedlings should be watered sufficiently to keep the potting mix
evenly moist, but not wet. Wet soil creates two problems: cold that
inhibits germination and root growth, and dampness that is a good
medium for fungal disease development.
Quarter to half strength fertilizer at should be added with the
water once a week after seedlings have true leaves. Use a complete
fertilizer with nitrogen, phosphorus, and potassium. Excess fertilizer
will burn tender roots and promote weak spindly growth.
February - March 2004: Seed Starting
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