by Tanya Wohlsclagel, Master Gardener
Did you ever sit inside, watching the snow fall, wondering how you will ever make it to spring? Still months or weeks to go before you can get the spade into the ground and get back to work on your next gardening project. Winter used to be long and boring for me, but now, beginning as early as December, the glossy and colorful seed catalogs start filling my mailbox. Time to get busy planning for another year! Many of the seeds you choose can be direct seeded outdoors when the temperature warms. Others need more time and must be started indoors. To my delight, some need to(or in a pinch could) be started as early as January!
Growing your own plants from seed is more economical, gives you a broader selection of plant varieties, can give you a jump on growing certain plants and is a nice hobby for gardeners in the winter and early spring. In the following text, I will give you some information on how to successfully grow plants from seed indoors.
Some people do have success growing on a windowsill. Unfortunately, I am not one of those people. The problems I experienced with tiny, emerging seedlings is that they did not get enough light. This caused most plant varieties to stretch and fall over. If you are lucky enough to have a large, south facing window or a south facing sun porch, then you likely could grow well. I am lacking good south windows so I grow with fluorescent lights in my basement. I use one “grow” tube and one cool tube that I purchase from the hardware store to give the full spectrum of light that the plants need. The “grow” tube could also be a “plant tube”, “aquarium tube” or just a “warm” tube. It is important that the fluorescent light be on an adjustable chain (fig 1) or be in an adjustable plant stand (fig 2) so you can raise the light as the seedlings grow. Keep the tubes within 6 inches of the top of the plants. The basement is a nice growing area because it is slightly cooler than room temperature that is in the rest of my house. Most seedlings prefer 60-65 degrees F. Warmer and they may become leggy (tall and spindly) I also make sure I do not use old tubes. Tubes loose their effectiveness over time, so be sure to replace them every 2 years. The fluorescent lights should be placed on a timer or you can turn them off and on, giving the plants 14 to 16 hrs of light per day.
Something that took me a long time to realize is that plants germination requirements vary greatly and are sometimes far different from their growing requirements. For example, the Geranium seeds I bought from Vesey's Seeds need to be covered lightly, kept at 75 degrees and kept in total darkness until they germinate. Wave Petunias on the other hand, need only to be pressed into the soil surface, kept at 75 degrees and do not desire total darkness.
Many seeds like warm temperatures and it can be difficult to get these temperatures in your house during the winter. Consider buying a heat mat. I purchased mine from Halifax Seed about 6 years ago for around $30. It will give you a constant, appropriate temperature source of bottom heat that most of your seeds will enjoy. When you germinate, warmth and moisture are generally the most important things with which with to be concerned. Once germinated, bright light, cooler temperatures, nutrition, moisture and infection control are the most important things to consider.
To grow from seed, you will need a good quality growing medium. I like Pro-Mix. I have tried many other types but I have found I have had the most success with Pro-Mix. You will also need a good fertilizer. I like “Miracle Grow Quick Start”. It is designed for seedlings and does seem to work better than an all purpose fertilizer.
To begin, mix weakly with half of a cap of fertilizer into a 1 gallon jug of water. Seeds do not need fertilizer to germinate but as soon as the seedlings start growing, nutrition will already be taken care of. Put some Pro-Mix into a big bowl or bucket and add enough water to moisten the soil. This will take some good mixing, a good amount of time and a surprisingly large amount of water. You want the soil to be very moist, but not dripping. If you squeeze the soil, it should at that point, drip. Put the well moistened soil into new or very clean, sterile containers. The container that I prefer for this step is the one celled seed pack. Fill the container to ½ or 2/3 full. Gently firm soil in place.
Start seeds at the appropriate time. Some need to be started 10-12 weeks before last frost date and some need to be planted 4-6 weeks before last frost date. Though eager to start seedlings, I do mostly try to plant at the suggested time. Planting too early will occupy more space and the plants may need to be transplanted into bigger pots.
A majority of your seeds will need to be sprinkled onto the soil and then covered with a thin layer of moist soil, but check the individual seed packet because as mentioned before, the requirements do vary. Some seed packets will have very little information or no information but the internet can provide you with lots of tips and details on the specific plant you want to grow.
Once your packs are seeded, place them in a seed flat that is solid (no holes), add a little water to the bottom of the flat and place a clear dome over top. (fig 3) Place the flat on a seed heat mat, if you are using one. This flat with a clear dome is useful in keeping the seedlings from drying out. If you don't have one, put your pack in a clear plastic bag and loosely tie the top.
Monitor your packs every day. If the soil surface begins to dry, add water to the bottom of the flat. As soon as many or most of the seedlings begin to emerge in a particular pack, remove the pack from the dome and put under your lights. A seed flat is useful here too, for future bottom watering.
Continue to monitor your seedlings at least once per day. (fig 4) Now that they are no longer in the dome or in a bag, they will dry more quickly. When water is required, always water from the bottom. If your seedlings are in a flat, pour water into the flat. Don't add more water than the soil will absorb. If you add too much, pour it off. Plants will die if they sit in water for too long. The reason to water from the bottom is so the water stream will not flatten your seedlings and it is also your best defense against “damping off”.
Damping off is an invisible fungal infection which will cause new seedlings to topple over at the soil surface and die. There used to be a water additive product on the market called “No Damp”, but since it has been removed from store shelves, indoor seedling growers have had to use other forms of control.
Bottom watering is important to reduce splashing and moisture at the soil surface. Though you don't want the plants to dry out to the point of wilting or stress, it is good to allow the soil to dry a bit between watering. A sign that your conditions are too moist is the presence of green algae on the surface. (fig 5) Though harmless in small quantities, it may become so thick that it keeps plant stems more wet, risking rot. To resolve, gently cultivate the soil surface. Putting a fan on your seedlings on a low setting is helpful too. Always use sterile soil and sterile equipment. Sanitize your work areas, grow areas and tools every year. Don't plant seeds deeper than needed and do not overcrowd your containers. Do not over or under fertilize or your plants will be stressed and more susceptible to infection. Fertilizing once per week is enough, I use half strength while they are small. If a damp off infection occurs, remove the infected plants immediately, sanitize the area and do not handle healthy plants with contaminated hands or tools. One last defense against damping off is to sprinkle cinnamon, a natural anti-fungal, on the soil surface.
As your seedlings grow, you will first see the seedling leaves, or cotyledons. Soon after, true leaves will emerge and the seedling leaves will wither away. Now is the time to prick your seedlings out.
I always start the seeds in a “one cell pack” because I want to choose which plants to grow on in multi- cell packs. This will also ensure you will have a plant in every cell.
Move your pack to a work area. Make sure the soil is moist. Prepare your 4, 6 or 9 unit cell packs by gently packing full of well moistened soil and then using your tool, make a hole to the bottom in all of the cells. Your tool could be any kind of pointy thing. I like to use a sharpened but dull wooden pencil. Grasp a plant by a true leaf with your index finger and thumb. Place your lifter (pencil) in the soil under the plant and with effort by both hands, gently lift it out. Guide the roots into the hole in the cell. Plant the plant at the same level it was before and gently firm soil around the roots with the pencil. Be careful to never plant the plant deeper than it was. (there are just a few exceptions, such as tomatoes) Also be careful to never handle the plant by its stem. You may crush the delicate cells and it may topple the plant over.
Continue to do this for every seedling that you wish to grow. If there are any left over, it is nice to continue to grow them for a few days just to be sure that every plant you pricked out survives. Continue to monitor your seedlings daily, water when necessary, fertilize weekly, practice infection control, keep the lights within 6 inches of the plant leaves with 14 to 16 hours of lights per day. Increase the fan speed and turn it onto oscillate so the plants will become more rugged and sturdy.
When the plants are big, and hopefully healthy and vigorous, it is time to move them outside. But just think about the comfortable life they have had as you babied them for months! Regular amounts of water, relatively constant temperature and a gentle breeze from the fan. Before they go outside into the elements, they will need to be hardened off. Start by putting the plants in the shade, outdoors. Gradually increase the time outside, and gradually move into the sun. Don't allow the seedlings to wilt and protect the seedlings from strong wind and heavy rain. After a few days of gradually introducing your seedlings to the outdoors, the plants are ready to transplant into their new location.
Starting plants from seed is a fun and rewarding hobby that can be done while the ground is still frozen and the snow is falling. With some planning and following a few rules, you can grow sturdy plants of varieties that you just can't find at local nurseries, at a fraction of the cost. Get growing!