I forgot to bring in my seedlings after a day of soaking up the bright spring sun a few weeks ago. Every tiny plant survived the cold night air except the tomatoes. Every sprout on the tomato plant was lying flat, and no amount of tender loving care was enough to revive it.

Tomatoes can be the most frustrating and the most rewarding vegetable plant we grow. I realize night-time temperatures should be above 50 degrees before planting my tomatoes or leaving them out overnight, but there are other things to know about tomato seedlings.

When the time comes to plant, you want to set your plants so that only two or three sets of true, not the first-set, leaves are exposed. If your plants are tall — sometimes referred to as “leggy” — you may want to plant them horizontally, but still with two or three sets of true leaves showing. This allows roots to develop along the planted portion of the stem.

If your tomato seedlings are in a biodegradable container, do not remove it before planting. Other containers will need to be removed gently, usually by carefully knocking the pot to loosen the plant. If you find that the roots are tangled or wound, you will need to loosen them a little. After your tomato is planted, gently firm the soil around the plant so a very slight depression is formed.

Keep your transplant moist for three or four weeks, lightly fertilizing the first week. After your plants are established, water regularly from as often as three times a week for fast draining, sandy-like soils to once every 10 days, depending on how long it takes for the top three inches of soil to dry completely.

• UC-certified Master Gardeners are available to answer your gardening questions from 9 a.m. to noon Tuesdays, Wednesdays and Thursdays at 953-6112 or mgsanjoaquin@ucdavis.edu. Questions for Heather Hamilton can be submitted to ucmastergardener@gmail.com.