top of page

Starting Seeds Indoors

If you want to grow plants from seed for your garden this spring, February is the time to start – planning and planting. There is a little more to it than dropping a seed in soil but reading this article will help you learn how to grow seeds successfully indoors.

Jim Lakin, M.D., Master Gardener

Starting Seeds Indoors

By February anything that’s green and growing is a welcome rebuke to the unending whiteness outside.  Of course, you can run to your favorite nursery and buy a big, beautiful blooming house plant, but I find great joy following a more quietly satisfying route---starting my own plants indoors from seed.  It really is not all that difficult if you pick the right plant.  


Different seeds require different treatments to wake up and start growing.  Some need to sit in a moist cold environment for 4 to 8 weeks—stratification.  Others, with tough coverings need to be roughed up a little bit to get going--scarification.  Other seeds benefit from an initial soaking in water to loosen up the coating.  Others need a few minutes in boiling hot water to kick start the germination process.  You can find out if the seed you select needs any of this “special handling” by consulting the catalogues of the seed companies from which you purchase them.  If you are picking up a packet locally, be sure to carefully read the fine print for any recommended pre-planting treatments.  Many commercially processed seeds are ready to sew without further ado.


Once your seeds have been through pre-treatment, you will need a container with good drainage.  This can be as simple as a plastic food container or milk carton bottom with a liberal number of holes poked in the bottom or more elaborate seed germination trays available at local garden stores or garden departments of “big box” wholesalers.

Cell flats can be ideal yet inexpensive reusable germination containers

If you are shopping for containers, also pick up some seedling mix.  There are a number of mixtures commercially prepared for germination.  Later, as the plants grow, you’ll want to transplant into potting soil.  Do not use garden soil or top soil.  These are way too heavy and you’ll get lousy germination results.  Plant your seeds to a depth roughly equal to the diameter of the seed.  You will want to place a transparent cover e.g., clear plastic, Saranwrap, over the container to keep up the humidity until the plants develop. 


What to do next depends on how much you want to invest in the process.  If you have a sunny window-sill that stays close to room temperature around the clock, that may be all you need.  Most folks have better results using grow lights which permit setting up away from windows, which tend to get drafty. Run you lights 12 hours per day.  Also, the addition of seedling heating pads can help a lot especially if you keep the thermostat turned down in the house.  Keep the medium moist.  Check at least every two days and water as needed.  It may take several weeks before you see those little green guys popping out of the soil.  Germination times vary widely.  Again, read the fine print on the seed packet for guidance.

Seedlings growing vigorously in a warm humid environment

Once the seedlings have appeared, be sure to keep the germination media moist, the grow lights on and let nature take its course.  After a few weeks, the root system may have completely filled the medium.  It’s time to transplant.   If you are using germination trays, you usually can pop the small plant out with a spoon or other small scoop.  Transplant them into well-draining pots.  I usually use 4-inch diameter light plastic ones which are cheap and readily available.  As the plants get bigger consider adding a small amount of liquid fertilizer diluted to one-fifth to one-tenth of the manufacture’s recommended concentration.  Continue to keep them warm and watered with ample light.  Then, start watching for the trees to green, the birds to sing and the last frost to pass.  Once that happens, it’s time to transplant your beautiful plants into the garden!


For more information, check out the University of Minnesota Extension:

https://extension.umn.edu/planting-and-growing-guides/starting-seeds-indoors/


Photo credit: University of Minnesota Extension

bottom of page