Starting indoors, in a container of well moistened, sterile seed-starting mix, make shallow furrows with a pencil or chopstick about 1/4 in. deep. Sow seeds by dropping them along the bottom of the furrows 1/2 in. apart.
Gently pinch together soil to cover each furrow, covering seeds 1/4 in. deep. Water gently and label each variety. Put container in a warm place, 75-80˚ F. As soon as seed begin germinating and stems start to show above the soil, it’s critical to provide a strong light source such as florescent bulbs or a very sunny window
Day 7 – Seedlings have germinated. First to appear are “baby” or “cotyledon” leaves. Careful labeling of each variety is important as they all look alike.
Day 15 – Seedlings are still tiny with just baby cotyledon leaves, but growing well. Note the nice green color of the baby leaves. This indicates that plants are getting enough bright light to thrive.
Day 30 – The first set of “true” tomato leaves begin to appear above the baby cotyledon leaves. The best example of this is in front of the pencil eraser in this picture.
Now that true leaves have emerged on all the seedlings, it’s time to transplant seedlings to larger individual containers so they have enough room to properly grow and develop. This process is called “pricking out” the seedlings.
To “prick out”: lift seedlings from below, holding each one gently by their baby cotyledon leaves and scooping up entire soil ball from below. We find an old fork works well for this.
If roots have grown together into a clump, gently tease seedlings apart, holding by baby cotyledon leaves.
Transplant each seedling into its own container (at least 3-4 in. in diameter) filled with good quality, well moistened potting mix. Make a hole to receive each seedling.
Insert each seedling into the hole to the base of its cotyledon leaves.
Tomato seedlings will readily grow new roots along their buried stems and the resulting plants will be sturdy and vigorous. Gently water in the seedlings to settle the plants.
Here are examples of what healthy and cold stressed seedling look like. Remember that seedlings need to be kept at about 65 – 70 degrees after they have true leaves and until they are ready to go into the garden.
When spring weather has warmed up and night temperatures are regularly in the 55 degree range, it’s time to plant well rooted, established seedlings outdoors. First plan to acclimate your plants: move them outside into the sun, first for a few hours , then gradually increasing over a weeks’ time until they are in full sun all day. this process is called “hardening off” and it avoids transplant shock
At transplanting time, if hardened off young plants are more than 6 in. tall, remove the bottom branches before planting. New roots will form along the buried stem.
Prepare the hole to receive the seedling
Tip out plant by overturning pot to squeeze or tap out the entire root ball. Note the snipped off lower branches on this example ready to go into the ground.
Settle the seedling into the hole, so the entire stem will be covered up to where leafy branches begin. Pull soil around the plant and firm.