How to Grow Matthiola From Seed

Starting Matthiola Indoors

• 1

  Calculate the best day to sow stocks for spring gardens by counting back five or six weeks from the last expected frost date for your area. Your local garden center or extension service will tell you that date if you're unsure. For fall bedding, start Matthiola seeds in mid- to late-July.

• 2

  Fill peat pots, small flower pots or starting flats with packaged seed-starting mix. To avoid damping-off disease, all containers must be clean. Sterilize hand-washed, recycled containers by running them through the dishwasher or dipping them in a solution of one part household bleach to 10 parts water.

• 3

  Set the filled pots on a tray and water them to dampen and settle the sowing medium. Pour off any accumulated water after 10 minutes.

• 4

  Place two seeds on the top of each pot and press them gently into the mixture. Do not add more medium over the seeds -- they need light to germinate.

• 5

  Mist the pots lightly with the sprayer to dampen the seeds, then cover all but one corner of the pots with plastic wrap to help conserve moisture.

• 6

  Place the tray of pots near a window. They need warmth and bright light but not direct sunlight. The top of a refrigerator is ideal. If necessary, mist occasionally to keep the seed starting medium moist but not soggy. Indoor germination usually takes seven to 10 days.

• 7

  Remove the plastic wrap as soon as the first seeds germinate. Move the tray to a sunny window or place it under grow lights. For stockiest growth, position the grow lights 2 to 3 inches above the top of the seedlings. Rotate window-grown seedlings daily for even growth.

• 8

  Thin seedlings to one plant per pot after they develop their first set of true leaves. Pinch off the extra plant rather than pulling it to avoid disturbing the soil.

• 9

  Water seedlings often enough to keep the soil moist but not soggy. Always drain away the extra water in the tray after 10 minutes.

• 10

  Feed the seedlings weekly with an all-purpose liquid fertilizer diluted to one-quarter strength.

• 11

  Harden off stocks for a week before planting into the garden. Move the plants to a sheltered area outside during the day and then back indoors in late afternoon. You can plant your Matthiola seedlings outdoors when all danger of frost is past.

Starting Stocks Outdoors

• 12

  Prepare a planting bed in full sun or partial shade. Stocks grow best in rich, well-drained soil with a pH between 6.0 and 7.0. Test the pH with a test kit or pH meter, or send a soil sample to your local extension service. You can direct-seed stocks outdoors around the last frost date.

• 13

  Mark planting spots 12 inches apart. Place two seeds at each interval and press them gently into the soil, but don't cover them. Matthiola seeds need light to germinate. Insert a plant label so you remember where you've planted the seeds.

• 14

  Mist the seeds with a sprayer. Keep the soil moist but not soggy. Direct-sown Mattiola seeds take 10 to 20 days to germinate.

• 15

  Thin the seedlings to one plant per spot as soon as they develop their first set of true leaves. Pinch, don't pull, the extra plant.

• 16

  Feed the stock seedlings weekly with a liquid fertilizer diluted to one-quarter strength. Once the seedlings are 4 to 6 inches tall, change the dilution to one-half strength. When the seedlings are 6 to 8 inches tall, change to a fertilizer formulated for flowering garden plants, following the directions carefully for the correct amount to apply.