Estimate How Many Seeds to Plant

Examining your seeds, you note that you received 350 in your tomato packet with a germination rate of 90 percent. This number means that of your seeds, 35 are anticipated not to produce. But that is still a lot of seeds, even if you wanted to grow a dozen plants. Using the end of a pencil, you poke a hole approximately four times the diameter of the seed and sow two. Sprinkling vermiculite over the top of the seeds, you are content with your work. In the end, you decide to start twenty because it's your first time and you want to have backups. At least if they all start, you can give away extras to friends and family to grow in their yards!

Lighting and Temperature

Ensuring your plants have the right amount of light and a regulated temperature is essential for proper germination. To begin, let's examine light options for your seeds.

Are you planning on sprouting your seeds with natural sunlight or with an indoor light? It is possible to use sunlight and supplement your home lighting. Still, there are things to consider, like how some seeds prefer darkness to germinate. If some of your plants need shade, consider adding a cover to the container in place of lighting.

Growing in Natural Light

Were you planning on using natural light for at least part of your germination? Make sure you have a south-facing window exposing them to indirect sunlight. Direct sunlight may be too much in the early stages of growth. 

Why a south-facing window? In the northern hemisphere, this is the side that will receive the most sunlight and, as such, is the favorite spot for most plants. Aim to provide them a cycle of approximately 15-hours of light and 9-hours of darkness, but every plant is different. Schedule your supplemental lights to come on a few hours before sunrise and turn off a few hours after sunset.

Also, as your seeds germinate and begin to sprout their first leaves, be sure to turn the tray often. Plants like to reach towards the light (i.e., sun, lamp, etc.), and by rotating the container daily, the stem develops evenly. The last thing you want is vegetables with stems so weak they struggle to hold the weight of their produce.

Growing Under Fluorescent Lights

When growing under fluorescent lights, aim to keep the bulb a few inches above the tops of the seeds and seedlings. As the plant grows, it will reach up towards the light above it. If it is too far away, the plant will devote more time reaching for the lightbulb than developing a sturdy base. The resulting leggy plant will still produce, though weakly.

Please note that keeping plants too close to high power lights (i.e., High-Pressure Sodium or Metal Halide) can also be detrimental. The heat produced by these lamps may be too much for the tender seeds. The goal should be to keep your seeds warm but not too hot. Aim for a daytime temperature between 65-75F (18-24C). Don't let the night time temperatures fall below 55F (13C). An excellent way to maintain these temperatures is to place a heating pad under the tray.