Seed Starting Indoors

Phil Peters
Adam's County Master Gardener Program

Many gardeners leave seed propagation to the greenhouses. Either they donít have the time, or they lack the confidence to set out on their own; some have had bad luck in the past and are frustrated. Seeds that donít germinate, or germinate, then die; certainly do nothing for the ego. Yet starting seeds is rewarding and can be lots of fun.

There are probably as many ways to start seeds indoors as there are gardeners who do it. It can be as simple as planting the seed in a cut off milk carton set on a sunny window sill, or it can be as elaborate and scientific as you wish to make it. Here are some suggestions that will bring sure-fire results without being hard on your wallet.

There are only four requirements for successful seed starting: 1) fresh seed, 2) sterile growing medium, 3) proper lighting, 4) proper moisture level.

Fresh seed is critical. When purchasing seed, be sure the package clearly states that it is seed "packaged for 2010." If it is not labeled for 2010, donít purchase the seed. Out of date seed does not have the same germination rate as fresh seed and will only lead to frustration. Purchase seed from a seed company or garden center that has a reputation for quality.

A sterile growing medium (soil) is essential. Using soil from the back yard is a recipe for disaster since it brings in too many potential problems that can keep the seed from germinating or killing it shortly after does. Damping off is the most obvious fungus that enters in this way. The seed sprouts, the plant grows and inch or so, then mysteriously, one morning it is lying on the ground; the bottom of the stem died and could no longer support the plant. I use an inexpensive oscillating fan to keep the air moving and prevent this problem

Purchase sterile seed starting medium from the garden supply store. It is possible to sterilize your garden soil in the oven. This is a long, smelly operation, and you break down the soil structure in the process. A sterile starter mix has all the nutrients seeds need for proper germination and retains moisture without introducing diseases. You can also spread the starting soil in tinfoil cooking pans (1 or 2 inches deep), or put the soil in peat pots. Punch some holes in the bottom of the pans before filling them with starter mix. Peat pots and peat discs are also a good choice.

While seeds will do very well on a sunny windowsill, they need light for a long enough time to get a good start. Rather than purchase expensive color-balanced lighting, I use fluorescent light tubes in a garage light fixture I hang over the starting trays. You will get good results if you put in one white and one blue fluorescent bulb. Frankly, Iíve never checked which I have in them. After the growing season I put them back up in my workshop over the workbench.

Keep the fixtures very close to the seedlings, since light diminishes rapidly as we move away from the source. I start my seedlings in trays on plywood set up on sawhorses in the basement. I rig the fluorescent fixtures up to the rafters in the ceiling, suspending them on chains from cup hooks screwed into the ceiling. The lights are on inexpensive timers plugged into the wall. Using the chains I can adjust the height of the lights as the seedlings grow. Try to keep the light 2" to 4" above the seedlings. If you are lucky enough to have a sunny window, you don't have to worry about this. Nature will do the adjusting automatically. However, the starts will benefit from longer exposure to light than the spring day provides. I leave the lights on for about fourteen hours per day.

Most importantly, donít overwater your seedlings. This is the single most common cause of failure. I use commercially made sponge plugs set into Styrofoam blocks for my seed starts. Several popular seed catalog companies supply these starting trays. They are a miniature greenhouse, in effect, coming with a tray, Styrofoam insert with holes for the plugs, and a clear plastic cover with adjustable vents. It is impossible to overwater with these plugs.

You can be quite successful if you use peat pots filled with sterile starting soil, or the peat discs that you soak before placing the seed in them. However, with these you must be very attentive and not allow them to remain soaking wet. If the peat dries out completely, it can suck the moisture out of your plants. Donít let the medium dry out completely. It should be damp but not wet. If you use the tinfoil pans, punch holes in the bottom before you start. Why? So you can water your seedlings from the bottom up.

 If you use aluminum trays, punch holes in the bottom so you can set them in a pan of water. Let the water percolate up through the potting mixture. Then remove the tray and let it drain. This prevents damaging the emerging seedlings. It also prevents water from accumulating on the leaves and attracting disease.

So get out your gardening gloves and let the summer fun begin!

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