Spring is right around the corner and soon it will be time to start planting items in our gardens. While most plants can be direct seeded into the garden, many plants will benefit from being started inside then transplanted into the soil. This allows for more hardy plants and an earlier harvest.
The first step is to determine what you want to grow in your garden. There are many options available to assist you with selecting this year’s varieties. You should always obtain your seeds from a reputable source such as garden centers and seed catalogs. If choosing seeds from a business that does not specialize in plants, pay special attention to the package date to make sure the seed was packaged for the current year. Though most seed remains viable for about 3 years, germination decreases as seed ages.
Now you need to determine the date to plant your seeds. There are two pieces of information that needs to be known: the target date for transplanting outside and the number of weeks needed to grow the transplant. The target date for transplanting the cool-season crops such as broccoli, cabbage, cauliflower and onions is early April. I use April 10 as a rule of thumb but that can vary a week either direction depending on the weather. Warm-season crops like tomatoes, peppers and most annual flowers are usually planted about May 10. While the time from planting the seeds to transplanting to the garden varies depending on the species, 6 -8 weeks is a good estimate to use.
Do not use garden soil to germinate seed as it is too heavy and may contain diseases. Use a media made especially for seed germination. There are many options for containers you can use to start seeds but whatever you use should be sterile and free from harmful chemicals. While there are many commercial containers available, I have found that 16oz plastic containers that cottage cheese or sour cream come in work well for larger plants and yogurt containers are great for smaller plants. A few holes in the bottom for drainage allow me to repurpose these containers instead of throwing them in the trash. Their larger size also greatly reduces how much re-planting of transplants that I am required to perform.
Seed must be kept moist in order to germinate. Water often enough that the media never dries. 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.
Most plants will germinate in either darkness or light. All plants require adequate amounts of light once emergence occurs. South facing windows may not provide enough light so fluorescent fixtures are often used to provide additional light. Fluorescent lights produce much less heat than incandescent bulbs allowing them to be placed very close to the plants, 2 to 4 inches, increasing the amount of light received. Additional light produces stronger plants. Young plants do not react to day length, so lights can be left on as long as desired. Sixteen hours of light each day usually is sufficient. You can use a timer to automate the process.
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. 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.
Seedlings will need some fertilization for best development. Use a soluble houseplant fertilizer available in garden centers or plant supply sections of department stores. Young seedlings are easily damaged by too much fertilizer so apply at about half the recommended strength a few days after seedlings have germinated. After that, fertilize according to the recommendations on the fertilizer label.
Plants react to movement. Brushing over the plants with your hand stimulates them to become stockier and less leggy. Try 20 brushing strokes per day. Brushing will not compensate for lack of light or overcrowding. Plants grown under inadequate light will be spindly regardless of any other treatment.
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.
For more information on this or other weeds in your lawn, check out our guide sheet G6570 Starting Plants Indoors From Seeds on line at http://extension.missouri.edu/p/G6570 or stop by your county Extension Center to obtain a copy.