BUFFALO, Minn. — Growing your own seedlings is a great way to try out new varieties of plants that you may see in seed catalogs but are not available at your local nursery. It can also be more economical than purchasing seedlings.
Growing plants from seeds is easier than most people think. The trick is planning ahead so that your seeds have adequate time and optimal growth conditions. Most seeds need 4-8 weeks of indoor growing time before they are ready to plant out, so March is the ideal seed starting time in Minnesota.
Seeds should be started in an area with good air circulation but no large temperature fluctuations or cold drafts. While many people try to start plants on windowsills, the radiant cold-heat fluctuations are not good conditions for seedling growth, and many windows provide inadequate light. A basement or interior corner of the house lit with artificial lights is an ideal location.
Both florescent and LED bulbs can be used in place of commercial “grow lights”, which tend to be more expensive. Using either two “cool” or a “cool and natural” spectrum combination will provide adequate light for seedlings. Plants should be 2-4 inches from the light while growing, so it’s important that either the lights can be raised and lowered by hanging them from adjustable chains, or that shelves can be adjusted as plants grow taller. Seedlings need at least 8 – 12 hours of darkness daily to mimic outdoor conditions. An automatic timer can be useful in assuring adequate but not too much light exposure.
Heat mats are beneficial, especially when starting tomatoes, peppers, eggplant, and other plants that prefer warm soil conditions. Electric heat mats are available online or where seed starting supplies are sold. Heating pads for human use are not safe around moisture and do not provide the same level of temperature control, so they should not be used.
A seed starting mixture is lighter than typical potting soil and is easier for tiny roots to establish themselves in. It can also be mixed with light texture potting soil. Check soil moisture about ½ inch below the top daily and only water as needed. Be careful not to overwater, as tiny roots decay quickly in constantly wet soil. Spraying seedlings with a mister can be helpful in dry, indoor conditions.
Seeds should be started in small containers. Several seeds can be planted in each space, then thinned out as needed. Domed covers that have openings to allow for air circulation can be useful but are not necessary.
Seedlings should be hardened off about 2 weeks before you plan to plant them into your garden beds. Start by putting them outside in a sheltered location for a few hours, then bringing them in overnight. Gradually increase the exposure to direct sun and the time outside until the temperatures are right for planting into your garden.
You can find more information and resources for starting seeds at home at the University of Minnesota extension website: extension.umn.edu/planting-and-growing-guides/starting-seeds-indoors
— Jamie Stang, Wright County Extension Master Gardener
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