To grow lisianthus from seed, you need to:
- Plant your seeds under growth lights
- Adjust your growth light as the plant grows
- Move your plants outside if you live in a warm area
The lisianthus’s showy, full petaled blooms are a wonderful addition to any garden.
It has the same long-stemmed elegance as roses but is twice as hardy as a cut flower.
However, growing lisianthus from seed is a long process that requires patience and diligence.
But once this graceful plant takes off in your garden, you’ll find it was well worth the wait.
The rest of this article will tell you everything you need to know about growing this popular annual, including what you’ll need before you start and how to ensure successful germination.
Can I Grow Lisianthus Where I Live?
Lisianthus best grows in hardiness zones 7-11.
But, if you live in a cooler climate, such as in zones 7-8, gardeners recommend bringing your lisianthus inside during the winter months.
Additionally, keep in mind that lisianthus is unique because it grows both as an annual, a bi-annual, or a perennial plant.
Yet, in zones 9-11, such as Arizona or southern California, it thrives as a perennial.
Why Should I Grow Lisianthus?
Lisianthus has the same full-petaled blooms and long stems as roses but can last up to twice as long in a vase as a cut flower.
Therefore, they are popular in flower arrangements and bouquets.
Plus, they come in a wide range of colors, including blue, red, white, pink, purple, and apricot.
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What Will I Need Before I Start?
To grow lisianthus from seed, you need to have:
- Lisianthus seeds (These are very small and fine.)
- A seed tray
- Peat moss
- Compost (or other organic material such as leaf mold or manure)
- Plastic (for covering)
- Grow lights
3 Steps to Grow Lisianthus From Seed
Step One: Plant Your Seeds
Because lisianthus seeds are susceptible to colder temperatures, it’s best to grow them inside so you can more easily satisfy their heating and light needs.
And since you need to sow the seeds in mid-winter, between December and January, so they’ll be ready to plant outside by late spring, you probably can’t give them what they need to grow outdoors.
For instance, the soil must be between 70-75 degrees Fahrenheit (21-24 C) for the seeds to sprout, and most places can’t offer this temperature.
So, to begin indoors, you’ll need to prepare a lightweight soil rich with organic matter, such as compost, manure, or leaf mold.
Keep the soil as close to 7.0 pH as possible, as acidic soil will cause discoloration and stunted growth.
Then, you can place the seeds into the soil about three times as deep as their diameter.
And since lisianthus seeds are so tiny, you should plant them just below the soil’s surface.
Next, you should water and fertilize your seeds well before covering the containers with plastic.
You need to then place the containers about ½ inch to 1 inch (1-3 cm) beneath grow lights and make sure they get 16 hours of light per day.
And, of course, keep your plants watered and never let your soil dry out between waterings.
However, be sure only to keep your soil moist.
If you overwater, you run the risk of root rot.
Finally, fertilize at half strength at every watering.
You should see sprouts in approximately two weeks.
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Step Two: Care for Your Seedlings
Once your seeds sprout, remove the plastic.
Also, the seedlings aren’t as sensitive to soil temperature now, so keeping the soil between 70- 75 degrees is no longer required.
But don’t let the temperature drop below 60 degrees (16 C).
Additionally, you should adjust the height of your grow lights at this time, so the lights are 2-3 inches (5-8 cm) above the tops of the plants.
Then, once the seedlings have 2-3 sets of leaves (after about 7-8 weeks), you can transplant the seedlings from the seed tray to slightly larger containers.
Lastly, you should now fertilize just once a week at half strength instead of fertilizing with every watering.
And if possible, water from the bottom and allow the soil to dry out more between waterings.
Step Three: Maintain Your Lisianthus
If you are planting your lisianthus in zones 9-11, they are relatively low maintenance since the winters in these zones are above freezing.
However, in areas with colder winters, expert gardeners recommend bringing your lisianthus inside during the autumn and winter months.
Overall, lisianthus prefers warm, dry air with full sun.
But if you live in a location with scorching summers, make sure you plant your lisianthus in a spot that gets afternoon shade.
Furthermore, ensure you place your lisianthus plants no closer than 6 inches (15 cm) apart, as they can grow quite large.
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To recap, the steps to grow lisianthus from seed are as follows:
- Start your lisianthus from seed indoors between December and January
- Prepare your soil
- Keep the soil between 70-75 degrees Fahrenheit (21-24 C)
- Cover your containers with plastic
- Place your containers under grow lights and keep the lights on for 16 hours per day
- Keep your plant watered, but don’t saturate the soil
- Fertilize at every watering
- In about two weeks, the seeds should sprout – once they do, lower the soil temperature to 60-70 degrees Fahrenheit (16-21 C).
- Plant them in larger containers when seedlings have between 2-3 sets of leaves.
- Re-plant them outside in late spring (May-June) and when plants are about 3-4 inches (8-10 cm) in height. Or, if you live in hardiness zones 9-11, move them outdoors in late March or early April.