One can start your tomatoes begining 6-8 weeks before setting them out in just about any type of container that can provide drainage. Just make sure to start with good seed and a sterile soil mix. I like to use a half-peat moss, half-vermiculite mix. Using a sterile mix will reduce the potential for soil borne disease problems.
Pre-moisten the mix slightly before planting. Plant seed about 1/4" (7mm) deep, cover with soil and water.
Seed should emerge in about 3-5 days at a temperature of 75-80F/24-27C degrees(min 50F/10C max 95F/35C). Optiumum temperatures for growth are 65-80F/18-27C days and 60-65F/16-18C nights. During germination, place them on the top of a refrigerator near the back to act as a heating source. Wait till after the seeds have germinated to put them in light as some genotypes (or varieties) require dark for germination to occur.
Keep the soil moistened till germination. When the seedlings start growing, allow the soil surface to dry slightly between waterings. I gauge watering by lifting the containers to check how heavy they are. I try not to water past 3pm. If seedlings sit overnight in cool and wet it can increase the chance of a disease problem or mold. That said, never let the seedlings wilt. If one misses a watering during the day and finds they needing water late afternoon, go ahead and water them.
Wait till the first "true leaves" appear to fertilize with a mild or dilute fertilizer solution that is based on a higher phosphorus content (P=the second number of analysis). These are often called "Starter" or "bloom booster" fertilizers and will work well for this purpose. P helps in fruit and root growth but it's also been found that much of the P in the fruit is acquired early during seedling in growth. I suggest using 1/2 of what the label recommends. One can always fertilize more. This way there shouldn't be any problems.
To start seed:
- good seed
- clean containers
- sterile soil mix
- warm temperatures for germination (75F/24C)
- once they emerge a good light source
Leggy plants can result from poor light, excessive watering, high nitrogen, warm temps or combinations of them. Cooler temperatures can slow plant growth down as well as cutting back on water and fertilizer. Light can be supplemented with flourescent shop lamps. If the plants are leggy when you plant thats, okay, just carefully burry the stem into the soil and roots will form along it.