Wild West District Blog
By Ron Honig- Horticulture Agent
Starting Garden Transplants from Seed
Gardeners who have always wanted to grow their own transplants still have time to produce their warm-season sets before planting time. This recent period of warm late-winter weather has no doubt made gardeners antsy to begin outdoor work. Producing one’s own garden plants for transplanting in May is a good way to satisfy a green thumb.
Following is a good set of guidelines for starting vegetable and flower garden transplants from retired K-State Horticulture Expert Ward Upham.
Purchase Recommended, Quality Seed: Start by taking a look at K-State’s recommended varieties at http://www.bookstore.ksre.ksu.edu/pubs/L41.pdf .
Upham says these plants have proven themselves across the state of Kansas and this is a good place to start when deciding what to plant. However, also talk to your neighbors, friends and your local garden center about what has worked well for them.
Obtain your seeds from a reputable source including garden centers and seed catalogs. If saving old seed, remember that most seed remains viable for about 3 years, however germination decreases as seed ages.
Determine the Date to Seed: Upham tells us there are two pieces of information that need to be known in order to determine the date to seed transplants: the target date for transplanting outside and the number of weeks needed to grow the transplant. Generally, it will be 6 to 8 weeks from planting seed until a plant is ready for transplanting.
Warm-season crops like tomatoes, peppers and most annual flowers are usually planted about early- to mid-May in southwest Kansas.
Sowing Seed: Garden soil is not recommended to germinate seed as it is too heavy and may contain disease organisms. Use a media made especially for seed germination.
Keep Seed Moist: Seed must be kept moist in order to germinate. Water often enough that the
media never dries, but use a container that allows excess water to drain away. Using a clear plastic wrap over the top of the container can reduce the amount of watering needed. Remove the wrap after the seedlings emerge.
Light: Upham says most plants will germinate in either darkness or light but some require darkness such as Centurea, Larkspur, Pansy, Portulaca, Phlox and Verbena. Plants requiring light include Ageratum, Browallia, Begonia, Coleus, Geranium, Impatiens, Lettuce, Nicotiana, Petunia and Snapdragon.
All plants require adequate amounts of light once emergence occurs. South facing windows may not provide adequate amounts and so fluorescent or LED fixtures are often used. Suspend
fluorescent lights 2 to 4 inches above the top of the plants. LED lights are much more variable.
Upham recommends using LED lights that are designed to grow plants and follow the manufacturer’s recommendations.
Regardless of the type of light used, leave the lights on for 16 hours each day.
Temperature: The temperature best for germination is often higher than what we may find in our homes especially since evaporating moisture can cool the germination media. Moving the
container closer to the ceiling (top of a refrigerator) can help but a heating mat is best for
consistent germination. A list of common plants and their optimum germination temperature can be found at the Extension office.
After plants have germinated, they can be grown at a cooler temperature (65 to 70 degrees during the day and 55 to 60 degrees at night). This will help prevent tall, spindly transplants.
Plant Movement: Plants react to movement. Brushing over the plants with your hand stimulates them to become stockier and less leggy. Approximately 20 brushing strokes per day is all that is recommended, but it will not compensate for lack of light or over-crowding.
Hardening Transplants: Plants grown inside will often undergo transplant shock if not hardened
off. Plants are hardened off by moving them outside and exposing them to sun and wind before
transplanting occurs. Start about two weeks before transplanting and gradually expose the plants to outside conditions. Increase the number of hours and degree of exposure over the two-week period.
