How To Grow Stock Flowers From Seed & How To Select For Double Flowers

Stock flowers Matthiola incana would have to be on the top of my list the most beautifully scented flower, its vanilla and cinnamon scent is just delicous! 
Stock flowers are an excellent annual cool weather crop and withstands super cold temperatures. 
We are one of Australia's very few suppliers of the stock stoX varieties which have beautiful new unique colours, very uniformed flowers and it is also breed to be able to select for easier select for double flowering plants at the seedling stage (i'll talk more about this below). For most modern stock flowers if not selected they will produce 55% doubles and 45% singles.


Germination Tips

  • I would recommend raise seedling over direct sowing.
  • Stock seeds can be sow autumn and late winter.
  • Start by using the best possible potting mix you can get your hands on. Then fill your pot (I like single cell pots, which prevent roots getting tangled. overcrowding and transplant better) with the soil and dampen the soil with water.
  • Surface sow 2 seeds into each cell on top of the soil and cover with a layer of vermiculite to hold the seeds in place. Light is needed for the seeds to germinate.
  • Water by using a mister or bottom water to avoid the seeds washing away, keep moist until seeds germinate.
  • The seeds will germinate between 7-14 days at 18-24 degrees.
  • Succession planting every 2 weeks for multiple harvests.
Selecting for doubles at the cotyledons (first leaves) stage. This can be tricky, but can become most visible after a cold treatment. This can be achieved by putting the seedling tray in the fridge/ floral cooler or if its very cold outside of your growing area this may be sufficient, do this as soon as the seeds have germinated for 4-7 days at 5 degrees. Then after the cold treatment keep the seedlings at 15 degrees for a day or two, make sure the seedlings are well watered to avoid them drying out. Post cold treatment you will be able to see that the leaves of the double flowering plants will be light green, and they leaves of the single plants will be a darker green and go ahead and select for doubles by removing the seedlings with the darker leaves. This sometimes may still be possible without a cold treatment. 
Planting Tips
  • Once the seedling have reached around 6 weeks of growth, two sets of true leaves it is time to harden the seedlings off. Do this by putting the seedling outside for a few hours on the first day, gradually working up to a full day to prevent any transplant shock.
  • Make sure they do not become root bound. Any stress will cause the flowers to bloom on shorter stems.
  • When choosing a position in the garden bed, make sure it has full sun and well draining soil.
  • Space the seedlings 10-20cm apart.
  • Some varieties will grow up to 75cm and will need netting support.
  • For watering, drip irrigation at the base of the flower is recommended, overhead watering will damage the flowers when in bloom.
  • Pinching out the column varieties is not recommended as it will stop the flower from producing flowers, column varieties are one flower per stem.
Harvesting Tips
  • Stock flowers take 90-100 days from seed to bloom.
  • Harvest when 1/3-1/2 of the flowers open, they can last a week in a vase.
  • Stock flowers are edible, and dry well if hung upside, they even keep there lovely scent!