Push the seed below the soil, about 1/3 inch deep, with your finger. Backfill the hole with soil to cover the seed and lightly firm the soil in place.
Place a coffee filter at the bottom of a 4-inch pot. Fill the pot with potting soil to within 1/4 inch of the rim. Lightly press on the top of the soil with your fingers to firm it. Fill one pot for each seed you want to plant.
Fill a shallow container, like dishpan, with 3 inches of water and place the pots in the water. Allow the pots to soak until the top of the soil is visibly moist.
Remove the pots to a drainage rack so the extra water can drain away.
Tangelos, a hybrid of mandarin orange and grapefruit, are oblong in shape and look like oranges. They are juicy with less pulp than regular oranges and can be eaten fresh off the tree or used in salads and cooked dishes. You can grow your own tangelo tree by saving the seeds from a fruit and planting them into pots. These trees are hardy in U.S. Department of Agriculture Plant Hardiness Zones 8 through 10. Gardeners living below Zone 8 can grow tangelos indoors.
‘Nova’ –a ‘Clementine’ tangerine and ‘Orlando’ tangelo cross made by Dr. Jack Bellows in 1942, first fruited in 1950, and released by the United States Department of Agriculture’s Horticultural Field Station, Orlando, Florida, in 1964. Fruit is oblate to rounded, of medium size, 2 3/4-3 in (7-7.5 cm) wide, 2 1/2-2 3/4 in (6.25-7 cm) high; peel is orange to scarlet, thin, slightly rough, leathery, easy to remove; pulp dark-orange, with about 11 segments, of good, sweet flavor; seeds numerous if cross-pollinated; polyembryonic, green inside. Early in season (mid-September to mid-December). Does very well on ‘Cleopatra’ rootstock. The tree resembles that of the ‘Clementine’ tangerine, its twigs are thornless, and it is more cold-hardy than ‘Orlando’. This cultivar is self-infertile and trials have shown that ‘Temple’ tangor is a good pollenizer.
Tangelos range from the size of a standard sweet orange to the size of a grapefruit, but are usually somewhat necked at the base. The peel is fairly loose and easily removed. The pulp is often colorful, subacid, of fine flavor and very juicy. The trees are large, more cold-tolerant than the grapefruit but not quite as hardy as the mandarin. Nucellar embryos are not uncommon in these hybrids and most of the cultivars are self-sterile, so a majority come true from seed. Tangelos are not commonly grown in California but are produced commercially and in home gardens in Florida. They are much more satisfactory on limestone in southern Florida than the sweet orange and are prized for their quality.
‘Orlando’ (formerly Take’)–result of ‘Bowen’ grapefruit pollinated with ‘Dancy’ tangerine, by Dr. Swingle in 1911. The fruit is oblate to rounded, of medium size, 3 in (7.5 cm) wide, 2 3/4 in (7 cm) high; peel deep-orange, slightly rough, not loose; pulp deep-orange, with 12 to 14 segments, melting, very juicy, sweet; seeds 10-12. Early in season but after ‘Nova’. A good commercial fruit in Florida. Needs cross-pollination by ‘Temple’ tangor, or by ‘Dancy’ or ‘Fairchild’ tangerines. The presence of honeybees, even without interplanting with a pollinator tree, has greatly increased yields. ‘Cleopatra’ mandarin is often used as a rootstock on sandy soils, but higher yields have been obtained on sweet lime and rough lemon in Florida. In Texas, ‘Orlando’ is most productive on ‘Swingle citrumelo’, ‘Morton citrange’, ‘Rangpur lime’ and ‘Cleopatra’ mandarin. Fruit quality is best on ‘Morton citrange’, sour orange, ‘Sun Cha Sha Kat’, ‘Keraji’ and ‘Kinokune’ mandarins.
‘Seminole’– a hybrid of ‘Bowen’ grapefruit and ‘Dancy’ tangerine; oblate, not necked; medium-large, 3 1/4 in (8.25 cm) wide, 2 3/4 in (7 cm) high; peel deep red-orange, thin, firm, almost tight but not hard to remove; pulp deep-orange with 11-13 segments, little rag, melting, of fine, subacid flavor; seeds small, 20-25, green inside. Early in season but holds well through March. Tree vigorous and high-yielding, scab-resistant; leaves with faint or no wings, tangerine-scented.
Among the better-known tangelo cultivars are:
Cover the seed flat with its plastic cover and place it on the heat mat. Adjust the temperature of the mat to as close to 85 degrees F as possible.
Gently tamp the medium down with a pestle or the flat end of a clean glass to make sure it covers the entirety of the seed. Water the medium with distilled water from a watering can until water drains from the flat.
Mix the peat moss with 1/4-gallon each of sterilized horticultural perlite and sterilized horticultural vermiculite by hand in a container. Moisten the propagation medium with a bit of water to make mixing easier.
Mist the seeds each day with a few spray of distilled water from a spray bottle to maintain humidity in the enclosure.
Extract the largest, most-robust, seeds from several mature tangelos, either by collecting them when you use the fruit or by cutting the fruit open and pricking them out with a wood skewer. Place the seeds in a sieve.
Fill the cells of a seed flat with the propagation medium. Use one 2-inch cell for each seed. Insert each seed 1/4- to 1/2-inch deep in the center of the medium in each cell. Cover the seed with propagation medium until the soil line is level.
Soak 1/2-gallon of sphagnum peat moss in warm water for one hour. Remove the peat moss and squeeze the water from it. Place a heat mat in an area that receives full sunlight and with a temperature as close to 85 degrees Fahrenheit as possible.
Botanists at the U.S. Department of Agriculture Horticultural Research Station in Orlando crossbred “Duncan” grapefruits (Citrus paradisi “Duncan”), which grow in U.S. Department of Agriculture plant hardiness zones 9 through 11, with “Dancy” tangerines (C. reticulata “Dancy”), which grow in USDA zones 8 through 11, in 1931. This cross resulted in the “Minneola” tangelo (C. paradisi “Duncan” x C. reticulata “Dancy”), hardy in in USDA zones 8 through 10. “Minneola” tangelos often grow true from seed, so you can propagate the trees at home by first germinating the seeds at around 85 degrees Fahrenheit in a sterile potting medium.
Run cool water over the seeds for one or two minutes to rinse off residual sugar and place them in a bowl. Cover the tangelo seeds with cool water and allow them to soak for eight hours in aerated or carbonated water. Soaking the seeds decreases germination time.