Katz Formula Mix
Matthiola incana
Long stems with 1 1/2-2" blooms in apricot, bright pink, wine red, pale purple, creamy yellow, dark purple, pale pink, and pure white. Early blooming one-cut series. Performed well in our spring, early summer, and fall trials. Good uniformity in bloom time and stem length. 55-60% double-flowering without selection; some selection possible. NOTE: This variety produces one flowering stem per plant. Pinching is not advisable as it will terminate flowering. Edible Flowers: The peppery, clove-like flavor of the flowers lends itself well to use as a garnish on salads, desserts, and drinks.
Harvest
90-100d
Days to harvest
Sun
Full sun to partial shade
Zones
6–10
USDA hardiness
Height
1-3 feet
Planting Timeline
Showing dates for Katz Formula Mix in USDA Zone 7
All Zone 7 flower →Zone Map
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Katz Formula Mix · Zones 6–10
Growing Details
Zone-by-Zone Planting Calendar
| Zone | Indoor Start | Transplant | Direct Sow | Harvest |
|---|---|---|---|---|
| Zone 3 | April – May | June – July | June – August | — |
| Zone 4 | March – April | June – June | June – July | — |
| Zone 5 | March – April | May – June | May – July | — |
| Zone 6 | March – April | May – June | May – July | — |
| Zone 7 | February – March | April – May | April – June | — |
| Zone 8 | February – March | April – May | April – June | — |
| Zone 9 | January – February | March – April | March – May | — |
| Zone 10 | January – January | February – March | February – April | — |
| Zone 1 | May – June | July – August | July – September | — |
| Zone 2 | April – May | June – July | June – August | — |
| Zone 11 | January – January | January – February | January – March | — |
| Zone 12 | January – January | January – February | January – March | — |
| Zone 13 | January – January | January – February | January – March | — |
Succession Planting
Stock doesn't rebloom the way a cut-and-come-again zinnia does, but staggered indoor sows can stretch your harvest window by several weeks. Start a first tray indoors in early February and a second in early March, then move the first batch outside in late March to early April and the second in late April. Stop starting new seeds once daytime highs are reliably above 75°F — plants that go in after that point almost never set buds before summer shuts them down. In zones 8–10, a late-August sowing gives you a second run; those plants stay small through winter and flower in early spring before heat returns.
Complete Growing Guide
Long stems with 1 1/2-2" blooms in apricot, bright pink, wine red, pale purple, creamy yellow, dark purple, pale pink, and pure white. Early blooming one-cut series. Performed well in our spring, early summer, and fall trials. Good uniformity in bloom time and stem length. 55-60% double-flowering without selection; some selection possible. NOTE: This variety produces one flowering stem per plant. Pinching is not advisable as it will terminate flowering. Edible Flowers: The peppery, clove-like flavor of the flowers lends itself well to use as a garnish on salads, desserts, and drinks. According to Johnny's Selected Seeds, Katz Formula Mix is 90 - 100 days to maturity, annual, open pollinated. Notable features: Use for Cut Flowers and Bouquets, Edible Flowers, Fragrant.
Light: Full sun (6 or more hours of direct sunlight a day), Partial Shade (Direct sunlight only part of the day, 2-6 hours). Soil: Clay, High Organic Matter, Loam (Silt), Sand. Soil pH: Alkaline (>8.0), Neutral (6.0-8.0). Drainage: Good Drainage, Moist. Height: 1 ft. 0 in. - 3 ft. 0 in.. Spread: 0 ft. 9 in. - 1 ft. 6 in.. Spacing: Less than 12 inches, 12 inches-3 feet. Growth rate: Rapid. Maintenance: Low. Propagation: Seed. Regions: Coastal, Mountains.
Harvesting
Katz Formula Mix reaches harvest at 90 - 100 days from sowing per Johnny's Selected Seeds. Expect 1 1/2-2" at peak. As an annual, harvest continues until frost ends the season.
Seeds will ripen in August and September.
Harvest time: Fall
Storage & Preservation
Store cut stems in a clean vase with fresh, cool water (65-72°F) in a cool location away from direct sunlight and ripening fruit. Change water every 2-3 days for maximum freshness; blooms typically last 7-10 days. For preservation, air-dry stems by hanging in small bundles in a warm, dark, well-ventilated space for dried arrangements. Press individual flowers between parchment paper under books for 2-3 weeks to create botanical specimens or craft materials. For edible use, harvest petals in the morning and refrigerate in an airtight container for up to 3 days before using as garnish.
History & Origin
Katz Formula Mix is open-pollinated, meaning seed saved from healthy plants will produce true-to-type offspring. Listed in the Johnny's Selected Seeds catalog.
Origin: The Coast of Europe from Spain to Greece.
Advantages
- +Produces stunning 1.5-2 inch blooms in eight beautiful color varieties
- +Performs reliably across spring, summer, and fall growing seasons
- +High double-flowering rate of 55-60% without requiring selection
- +One-cut variety yields long stems ideal for floral arrangements
- +Edible flowers add culinary versatility with peppery, clove-like flavor
Considerations
- -Single stem per plant limits yield compared to pinchable varieties
- -Cannot be pinched back without completely terminating flower production
- -90-100 day growing period requires patient timeline planning
Companion Plants
Marigolds (especially Tagetes patula) and sweet alyssum do real work near stock — alyssum draws in parasitic wasps that knock back aphid populations, and marigolds discourage root-knot nematodes in the soil over a full season. Lavender and chives add scent layering that makes it harder for flying pests to zero in on one crop. Keep stock away from fennel, which releases allelopathic compounds from its roots that stunt a wide range of neighbors, and plant it nowhere near a black walnut (Juglans nigra) — that tree's juglone moves through the soil far enough to cause real damage to shallow-rooted annuals like Matthiola.
Plant Together
Marigolds
Repel nematodes, aphids, and other pests while attracting beneficial insects
Sweet Alyssum
Attracts beneficial insects like lacewings and hoverflies that prey on pests
Nasturtiums
Act as trap crops for aphids and cucumber beetles while repelling squash bugs
Lavender
Repels moths, fleas, and mosquitoes while attracting pollinators
Cosmos
Attract beneficial insects and provide structure without competing for nutrients
Chives
Repel aphids and Japanese beetles with their strong scent
Zinnia
Attract butterflies and beneficial insects while providing continuous blooms
Borage
Attracts pollinators and beneficial insects while improving soil health
Keep Apart
Black Walnut
Releases juglone toxin that inhibits growth and can kill sensitive flowers
Eucalyptus
Allelopathic properties suppress growth of nearby plants
Fennel
Inhibits growth of most garden plants through allelopathic compounds
Troubleshooting Katz Formula Mix
What you'll see, why it happens, and what to do about it.
Seedlings collapse at soil level, stems pinched and dark at the base
Likely Causes
- Damping off (Pythium or Rhizoctonia spp.) — triggered by overwatering and poor drainage
- Sowing too densely, which keeps humidity high around stems
What to Do
- 1.Water only when the top inch of mix is dry; don't let trays sit in standing water
- 2.Thin seedlings to at least 1 inch apart in the flat as soon as the first true leaves appear
- 3.Use a sterile seed-starting mix — not garden soil — and add a thin layer of perlite on top to keep the surface dry
Leaves develop gray, powdery coating, usually first visible on upper leaf surfaces in late spring
Likely Causes
- Powdery mildew (Erysiphe cruciferarum) — common on Brassica-family plants including Matthiola, especially with warm days and cool nights
- Overcrowded spacing that restricts airflow between plants
What to Do
- 1.Space plants at least 12 inches apart — 15 is better in humid climates
- 2.Apply a diluted neem oil solution (2 tsp per quart of water with a few drops of dish soap) every 7 days at first sign
- 3.Pull and trash heavily infected plants; don't compost them
Plants produce only leafy growth after transplanting, with no flower buds forming
Likely Causes
- Heat delay — stock (Matthiola incana) needs cool temperatures, ideally below 65°F at night, to initiate bud set; going into warm soil stalls them in vegetative mode
- Starting seeds too late indoors, so plants never get the cool establishment period they need before summer arrives
What to Do
- 1.Start indoors 8–10 weeks before your last frost and transplant out while nights are still in the 40s–50s°F
- 2.In zone 7, get transplants in the ground by late April at the latest — once daytime highs are consistently above 80°F, bud set stalls
- 3.In zones 8–10, try a fall sowing in late August instead; plants overwinter small and bloom before the following summer heat sets in
Frequently Asked Questions
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Growing Guides from Wind River Greens
Where to Buy Seeds
Sources & References
External authority sources used in compiling this guide.
- BreederJohnny's Selected Seeds
See the Methodology page for how this data is sourced, what's AI-assisted, and known limitations.