Seedling Care for Annual Cut Flowers: Potting On, Hardening Off, and Planting Out

Home grown flower bouquet

Nurturing annual plants for cut flowers from seedling to bloom is a rewarding journey. Understanding the processes of potting on, hardening off, and planting out is essential for cultivating healthy blooms.

Potting On: Giving Seedlings Room to Grow

As your seedlings develop true leaves—the ones following the initial pair—they often outgrow their starting containers. Potting on involves transferring these young plants into larger pots with fresh compost, providing ample space for root expansion.

When to Pot On

Once seedlings have multiple sets of true leaves and appear crowded, it's time to pot them on. Overcrowding can impede growth, so timely action is important.

Steps for Potting On

1. Prepare New Pots: Select larger pots and fill them with quality compost.

2. Gently Remove Seedlings: Carefully ease the seedling out by squeezing the base of its current container. Handle by the leaves to avoid stem damage.

3. Transplant: Place the seedling into the new pot, filling around it with compost to support the plant.

4. Watering: After transplanting, lightly water from above to settle the compost around the roots.

   
   
   
   

   

   Seedlings ready to be potted on

   
   

   

   Transferring seedlings into pots - use the leaves for lifting to avoid stem damage

   
   
   
   

   

   Healthy root system on seedling

   
   

   Hardening Off: Preparing Seedlings for the Outdoors

Before planting seedlings outdoors, they need to acclimatise to external conditions—a process known as hardening off. This gradual exposure helps them adjust to temperature fluctuations, sunlight, and wind, reducing transplant shock.

Steps to Harden Off

1. Timing: Begin hardening off about two weeks before the planned outdoor planting date.

2. Initial Exposure: Place seedlings outside in a sheltered, shaded area for a few hours daily, bringing them back indoors or into a greenhouse at night.

3. Increase Exposure: Gradually extend their time outside and exposure to sunlight over a week or more.

4. Final Adjustment: Leave them outside overnight towards the end of this period to acclimate to nighttime temperatures.

Hardening off potted on seedlings outside

Planting Out: Moving Seedlings to Their Permanent Home

After hardening off, seedlings are ready for planting in their final outdoor location.

Steps for Planting Out

1. Choose the Right Day: Opt for a calm, overcast day to minimize stress on the plants.

2. Transplant Carefully: Gently remove each seedling from its pot by squeezing the sides; avoid pulling on the plant.

3. Proper Spacing: Plant in rows, leaving about 15cm between each plant and row to allow for growth.

4. Firm the Soil: Lightly press the soil around each plant's base to eliminate air pockets.

5. Watering: After planting, gently water the seedlings to help them settle.

Healthy seedling with strong root system ready to be planted out

Planting out annuals - space them quite close approx 15 cm - to maximise your growing space

Regular monitoring and watering, especially during dry periods, are vital as seedlings establish themselves.

By carefully managing potting on, hardening off, and planting out, you'll set the stage for a thriving cut flower garden. Stay tuned for next week's article, where we'll delve into caring for your plants as they grow, including tips on harvesting, seed saving, and drying your beautiful blooms