Raising seedlings indoors can be a fun and rewarding hobby. Besides the personal satisfaction gained, raising your own seedlings will give you a head start on the growing season, save you money from buying plants, and most importantly, give you an unparalled selection in varieties not
available at the local nursery.
Begin your own seed starting adventure now!
1. Seed Selection
Carefully read seed packets and garden catalogs for seed germination requirements. If you’re a beginner, be sure to pick seeds labeled as easy or with a short germination time. Order seeds in early winter from garden catalogs to make sure you receive them in time. Check suggested advance starting dates on seed packets and mark your calendar.
Always start with clean containers with drainage holes. A variety of
containers may be used, from recycled yogurt cups to plastic pots or cell
packs. Deli clam-shell containers are particularly nice because they come
with a built-in greenhouse cover. You may also use biodegradable peat
pots. These are recommended for hard to transplant seeds such as cucumber
or zinnia. Be sure to sterilize used containers with a solution of 1 part
chlorine bleach to 10 parts water.
3. Soil Mix
Use a soilless commercial germinating mix for your seed starting. These
mixes are sterile, lightweight and the perfect texture for even fine seeds.
Never use garden soil which contains both weed seeds and fungi, a cause of
damping off. After you become an experienced seed starter, you may want to
experiment with your own mix of peat moss and vermiculite or perlite.
Several hours before planting, moisten the soilless mix with room
temperature water. Soilless mixes do not contain nutrients for plant
growth. Once seedlings have developed their first set of true leaves, begin
fertilizing with quarter strength water soluble fertilizer such as 15-30-15
4. Sowing Seeds
As a general rule of thumb, sow seeds to a depth of 2 to 3 times their
thickness. Tiny seeds and those requiring light to germinate should be
surface sown and gently pressed into the soilless mix. Seeds may be sown
directly into individual containers or sown in quantity in one container
and then transplanted. Gently mist containers after planting. Place
containers in a clear plastic bag. No additional watering should be
necessary until after seeds have germinated.
5. Light and Temperature
Place seeds in a warm location out of direct sunlight for germination.
Most seeds require a temperature of 65 to 75 degrees, while some such as
cabbage and snapdragons require cooler temperatures of 55 degrees. Watch
seeds carefully and once they have germinated remove their plastic covers.
Although you can grow on seedlings in a bright sunny window, fluorescent
lighting will give you a greater chance of success. No expensive equipment
is required. A simple shoplight with two 40 watt cool or combination warm
and cool bulbs will suffice. Keep lights 2-3 inches above plants for 14-16
hours a day. A timer comes in very handy for this.
6. Thinning and Transplanting
Once seedlings have developed at least one set of true leaves it’s time to
transplant or thin. For seedlings planted in individual containers, thin
to one seedling per pot by cutting off unwanted seedlings at the soil line
with a scissors or your fingernail. This prevents the roots of the
remaining seedling from being disturbed. To transplant seedlings into
individual containers, gently tease them apart with a small utensil such as
a plastic plant marker or pencil. Handle them carefully by their leaves
instead of their delicate stems. Poke a hole in the soil with a pencil and
plant seedlings at the same depth as they had been growing. Gently mist to
7. Hardening Off
The last step in seed starting is to harden your seedlings off. This is
a process that prepares pampered seedlings for the great outdoors. About
two weeks before planting outdoors gradually acclimatize seedlings by
placing them outdoors for short periods of time. Start by putting them
outdoors in a shady spot for an hour or two, and then gradually increase
duration of stay and exposure to sun. DO NOT put tender seedlings outdoors
on windy days or when temperatures are below 45 degrees. Seedlings should
have spent at least 1 overnight outdoors before being planted in the
For more information on seed starting be sure to check out Purdue University publication HO-14 Starting Seeds Indoors.(http://www.hort.purdue.edu/ext/garden_pubs.html)