1. Choose appropriate tomato varieties
Take time to find out about different tomato varieties. Grow types that are suitable for your climate and soil conditions. Ask local gardeners and nursery workers for recommendations. You can also gauge your selection on whether you’ll set plants in the garden or grow them in containers.
2. Start seeds at the right time
Check your local frost dates. Start tomato seeds about 6-8 weeks before it’s safe to set out plants in the garden. This allows time for germination, re-potting, and hardening off.
3. Use sterile containers
What’s most important no matter what type of container you use is that it is clean. Wash cells, cups, or trays in a light bleach solution before filling with potting soil. Make sure containers have holes in the bottom for drainage.
4. Use sterile potting mix
The starter mix’s main jobs are to get the seeds to sprout and to keep them disease-free until they have 2 sets of leaves. The best choice is a sterile potting mix, rather than soil from your garden, which is packed with fungi and bacteria. Choose a potting mix that is lightweight, holds water, and is light on fertilizer. Moisten mix before planting seeds.
5. Plant at appropriate depth
Use a pencil to poke a small hole for each seed. Plant a seed at a depth 4 times its diameter. Cover seeds with pinches of moistened soil.
6. Let there be light
Place containers in a sunny window or under grow lights. Tomato seedlings need 12-16 hours of light a day.
7. Check soil moisture daily
Mist or water them regularly but don’t overwater or roots will rot. Tomato seeds sprout in 5-10 days.
8. Re-pot seedlings
Once tomato plants have 2 sets of leaves, move them to a larger pot to help them build strong root systems.
9. Watch for and fix problems
Tomato seedlings are subject to damping off (cause: fungi in the soil), leggy growth (cause: poor lighting; too much heat or fertilizer), slow growth (cause: too cold; need for fertilizer), seed rot (cause: overwatering), or stuck leaves (cause: natural). To head off problems, plant tomatoes in sterile soil. Monitor them diligently and keep an eye on conditions – regulate air temperature, water, light, and fertilizer to keep seedlings healthy.
10. Harden off seedlings
About 7-10 days before planting tomato seedlings outdoors, acclimate them to temperatures, sunlight, and wind. Place them outside in shade or a protected area for a couple of hours, gradually increasing exposure until you can keep them out overnight.
About the Author
Kathy Widenhouse is a contributing writer for Mike the Gardener Enterprises, LLC and owner of Tomato Dirt (http://www.tomatodirt.com/), a leading source for information on growing tomatoes and using them.