It’s finally time! You’ve chosen the varieties, made the space and have all your supplies on hand. Plant!
If you have a self-watering seedling system, fill the reservoir with water and put the wicking mat in place first. Place the cell tray on the wicking mat before you fill it with soil-less mix. Fill each seedling cell or container with the moistened medium to the top edge. Press the mix lightly into the cell. Unless you are prepared to sacrifice the extra plants, plant only one seed per cell. I know from experience, that most gardeners cannot bear to cut off the stem of the least hardy baby plant if more than one germinates in a cell. This can lead to trying to transplant very tiny seedlings and often damaging the healthiest seedling left behind. If there is no sign of germination within a week in any individual cell, then plant an additional seed in that cell. Press the tomato seeds 1/8” into the soil-less mix or cover them with a small amount of additional medium. The seeds need to have contact with the soil to germinate; this can be achieved by sprinkling water lightly on the top of each cell. A tip: if you’ve had problems with Damping Off disease in the past, consider top dressing your newly planted seeds with finely milled sphagnum moss. Place your trays on the warm area. Some people like to put a plastic dome over the top of each cell tray. If you’re concerned that the cells may dry out this can be a good idea, but the dome should be removed as soon as sprouts appear.
Watch Me Grow! If the conditions are right, tomato seeds can germinate in 4 days! As soon as you see green growth from 50% of the cells, it’s time to provide the sun. If you wait too long, the stems will start reaching for brighter light. Place the seedlings under grow lights for 12-16 hours per day – use a timer. Now is the best time to provide air movement to prevent Damping Off disease. You may continue to keep the soil warm to improve root growth (although it is not necessary), but keep the air around the top of the plants cool. Air temperature that is too warm (above 60° at night or above 70° during the day) will also make the stems tall and leggy.
They’re up and growing! In just 7 days we have 90% germination!
No Wet Feet Please Keep the soil moist but not wet. Soggy soil can lead to disease problems and poor root growth. In the beginning, you will not need to water very often. As the plant roots fill in the soil area of each cell, you may need to water every day. If you’re using a self watering system, just check the reservoir regularly.
Feed Me! Feed Me! Feed Me? Each seed is a fully contained next generation plant. Until actively growing and the first ‘true leaves’ appear (http://gardening.about.com/od/gardenprimer/ss/SeedStarting_9.htm), there is no need to add fertilizer to the seedlings. Once you see the first leaves that actually look like tomato leaves is when to start feeding your young plants. Most seedling fertilizers (2-4-2) are water soluble and can be added when you water (or added to the reservoir). A balanced (even numbers of N,P and K) fertilizer or one that is lower in Nitrogen than Phosphorous and Potassium will work fine if that is what you have on hand. Start with one half the recommended dilution. As the plants grow, you may be able to ‘read’ its needs by how it looks (discussed later).
Pet Me Please. Everyone laughs . . . but it’s a great idea! Start petting the tops of your seedlings as soon as they have 2 sets of leaves. You want those wimpy little babies to grow into sturdy, strong plants that produce baskets full of tomatoes. The stem’s cell wall will not become sturdy until there is an environmental reason to do so. If you touch them, they bounce back and the cells become stronger. Think of it like a weak muscle on your arm; if it is not exercised with resistance – it cannot grow strong. So go ahead and laugh, but then go pet your plants!