Morning glory, Ipomoea tricolor, is a vine that blooms from seeds. Morning glory seeds are hard and should be nicked or rubbed with a file and soaked in warm water before planting. Some experts recommend soaking for two hours, others advise 24 hours. The seeds can be started indoors while the weather is still too cold outside, or directly outside after the last frost.
Sow one or two seeds in a 3-inch pot, 1/4 to 1/2 inch deep. Cover the seed with all-purpose potting compost together with perlite for extra drainage. Cover with another inch of potting compost and water well.
The sown seeds should not be kept in a windowsill but away from drafts and pets, and in a space with room for them to grow. It is better to grow indoor seeds under fluorescent light then the sun. A heat source from underneath is recommended for the seedlings. The temperature in the potting mix indoors can be lower than the air temperature of the room. Electric heating mats are available for this purpose. The potting mix should remain moist while the seeds germinate.
Fertilizing is not necessary until leaves appear, as the plant has everything it needs in the seed. After the last frost, the seedlings can be moved outside. If started indoors they will not be use to the sun, wind, or temperature changes. Two weeks before planting in the garden, they need "hardening off" by moving them outdoors for increasingly longer periods each day. They can start with a few hours in the shade and each day stay out a little longer with more exposure to the sun. Once they have been hardened off, they can be planted in the garden. They should be planted on a cloudy day or in late afternoon so as not to wilt in the hot sun.
Another seeding method, although used mostly in commercial seeding, is using a mixture of vermiculite and peat, without a true soil. The mixture is sterile, weed free, lighter weight and has an excellent texture for germinating seeds and seedlings. The individual containers are set in flats and filled with the mixture and water before the seeds are sown. Plant the seeds after the mixture and water have settled and the container is almost full.
After the last frost, the seeds can be planted directly outdoors. They ought to be planted about 1/2 inch deep. The soil should be kept moist. Seeds should germinate in about five to 21 days. The plants should be thinned to 4 to 6 inches apart. Also, they will need a trellis, mailbox, or fence for the vine to climb. Morning glories require full sun and phosphorus rich fertilizer two or three times during the season.