While you can buy forget-me-nots (Myosotis spp) at a garden center, save money by growing them from seed. Use the forget-me-nots as bedding plants or in border and rock gardens for cheery spring and summer flowers. They work especially well when planted around spring bulbs that will be fading when the forget-me-nots are ready to bloom.
Forget-me-nots generally grow in U.S. Department of Agriculture plant hardiness zones 3 to 9. Garden or woodland forget-me-nots (Myosotis sylvatica), which grow in USDA zones 3 to 8, are the most common but others are available. Seeds for true forget-me-nots (Myosotis scorpioides), which grow in USDA zones 5 to 9, and alpine forget-me-nots (Myosotis alpestris), which grow in USDA zones 3 to 9, are also easy to find. Forget-me-nots bloom in blue, pink or white.
Starting from Seed
Start forget-me-not seeds in moistened seed-starting mix or vermiculite two months before the last expected frost. Use either a seed flat or 2- to 3-inch pots. Make sure the pots or flats have drainage holes. Sow lightly, leaving about 1 inch between seeds. Do not cover the seeds because they need light to germinate. Just press them down gently to make sure they make good contact with the seed-starting mix or vermiculite.
Keeping them Moist
Cover the flat or pots with a flat piece of clear plastic or put the entire container in a clear plastic bag to keep the medium moist. Place them in a bright area out of direct sunlight with temperatures between 65 and 72 degrees Fahrenheit. Check the growing media every few days and gently mist with room-temperature water if it begins to dry. Do not let it dry out. The forget-me-not seedlings should sprout in 10 to 14 days. Remove the covering as soon as the seedlings emerge. Water them when the top of the potting mix or vermiculite begins to dry.
Thinning the Seedlings
Thin the seedlings to 6 to 8 inches apart after they develop one set of true leaves. The first set of leaves they develop are "seed" leaves which are not true leaves. Wait for another set of leaves which will look different from the first set. Snip the weakest seedlings off at the soil line with scissors that have been wiped with a cloth soaked in rubbing alcohol. Continue to keep them in bright, indirect sunlight with temperatures around 65 F.
Fertilizing and Watering
Continue to water the seedlings when the top of the media begins to dry. Give them one dose of fertilizer after thinning them. Use water-soluble 10-5-5 houseplant fertilizer with nitrate nitrogen rather than ammonium nitrogen. Dilute the fertilizer at a rate of 3/4 teaspoon per 1 gallon of water. Pour the fertilizer evenly over the germination mix after a regular watering.
Transplant the seedlings into individual pots with drainage holes in the bottoms two weeks after they develop their first set of true leaves. Use houseplant potting soil. Continue to water them when the top of the potting soil begins to dry.
Getting them Ready
Get the seedlings used to direct sunlight gradually. Begin setting them outside in bright or dappled shade in an area protected from drying winds for an hour or two during the day when there is no danger of frost. Move them into 30 to 60 minutes of direct morning sun after a few days. Increase the length of time they are exposed to the sun by about 30 minutes each day until they are in the sun for four hours each day. Allow the potting soil to dry slightly before watering.
Plant forget-me-not seedlings 9 to 12 inches apart in the spring after the last expected frost. Dig the planting holes just deep enough so the bases of the plants are no deeper than they were in their containers. Plant them in fast-draining soil that has plenty of organic matter. Mix a 2- to 3-inch depth of aged cow manure, compost, sphagnum peat moss, leaf mold or composted pine bark mulch into the top 8 to 10 inches of garden soil before planting. The pH should be between 5.6 and 7.
Plant forget-me-nots in partial shade or full sun. In areas with hot summers, plant them where they will get direct sunlight in the morning but shade in the afternoon.
Water and Fertilizer
Water forget-me-nots generously right after planting. Sprinkle 1/2 pound of 10-5-5 granular fertilizer per 50 square feet of garden area over the soil around them. Do not get fertilizer on the plants. Rinse it off with water if it gets on them accidentally. Spread a 2- to 3-inch layer of organic mulch over the soil to help keep it moist. Water the plants when the top of the soil begins to dry.