About Rio Grande Tomato: Rio Grande comes from the Italian strain of paste tomatoes. The University of California developed this variety to thrive in hot, humid weather; the USDA received the final product in 1994. Gardeners in southern regions appreciate this excellent tomato as one of the best paste tomatoes available for hot climates.
Rio Grande Tomato Germination: Start tomatoes indoors 6-8 weeks before the last frost of spring, sowing the seeds in a flat 1/4" deep and 1" apart. Keep the temperature at 70-75 degrees F until germination, as well as providing adequate light in a sunny window or under a grow light; keep the soil moist, but make sure drainage is adequate. When the second set of leaves emerges, transplant the seedlings into individual pots; bury the stems up to the lowest set of leaves to grow strongly rooted plants. A week before planting the seedlings outside, begin exposing them to the weather during the day to harden them; tomatoes cannot endure cold weather, and should not be transplanted outside until all threat of frost has passed. When the soil temperature reaches at least 70 degrees F, plant the seedlings in full sun and very rich soil; once more, bury the entire stem up to the lowest set of leaves. Space the plants 2' apart. For companion planting benefits, plant tomatoes with carrots or onions, but avoid planting them with cabbage or tomatoes.
Growing Rio Grande Tomato Seeds: Since temperatures below 55 degrees F can damage production, protect the plants if temperatures drop. A thick layer of mulch helps conserve moisture and control weeds; water the plants once a week, but avoid getting the leaves wet. Determinate, or bush type tomatoes, do not require staking.
Harvesting Rio Grande Tomato: Test the ripeness of tomatoes by pressing them gently; the flesh should yield slightly. The mature color also indicates ripeness. If the stem does not come easily off the vine, cut it with a scissors. Vine ripened tomatoes have the best flavor, but as soon as frost comes, all tomatoes should be harvested, even the green ones. Unripe tomatoes will ripen eventually if kept in a warm place out of direct sunlight.
Saving Rio Grande Tomato Seeds: Since cross pollination between most tomato varieties is unlikely, isolation is not a concern. Pick fully ripe tomatoes and cut them in half horizontally, across the middle; squeeze out the pulp into a container. An alternative method for smaller tomatoes is to put them in a blender and pulse the mixture, since the seeds are hard and slippery and will not be harmed. Let the mixture ferment for several days or until a thick layer of mold has formed; this process removes the gelatinous layer on the seeds. Pour off the mold and debris, saving the good seeds on the bottom. Rinse the seeds in a strainer under running water until they are clean, then spread them out to dry in a protected location away from direct sunlight. Stir them twice a day, and provide a fan to speed drying if the air is humid. Once the seeds are completely dry, store them in a cool, dry location for up to four years.
Detailed Rio Grande Tomato Info: Lycopersicon esculentum. Also known as Roma Rio Grande. Annual. 70-80 days. 10,000 seeds per oz. 48-72" height. 30-36" spacing. Produces elongated or pear shaped red tomatoes that average 8-12 oz. Determinate.