Potting On Lupin Seedlings: When and How to Give Your Plants a New Home

Are Your Lupin Seedlings Ready for a New Home?

Lupins, with their majestic spires of colourful blooms, are a garden favourite. But getting them from seed to a thriving plant requires a little know-how. If you’ve started your lupins from seed, you might be wondering about the next step in their journey: potting on. Let’s delve into the essentials of when and how to pot on your lupin seedlings to ensure they reach their full potential.

Understanding Lupin Seedling Development

Lupins, like many perennials, have specific needs during their early stages. Understanding their growth patterns is key to successful potting on:

• Early Growth: Lupin seedlings typically start in cell trays or small pots. They’ll develop a few sets of true leaves after the initial seed leaves (cotyledons) emerge. The development of these true leaves is a good indicator of when it’s time to consider potting on.
• Root System: Lupins have a taproot – a single, strong root that grows downwards. This taproot is crucial for their long-term health, allowing them to access water and nutrients deep in the soil. This means you need to give them enough space to develop.
• Overcrowding: Overcrowding is a common problem with seedlings. When seedlings are too close together, they compete for resources such as light, water, and nutrients. This can lead to weak, leggy plants.

Assessing Your Lupin Seedlings

Before you decide to pot on your lupin seedlings, evaluate their current condition:

• Size and Development: Are your seedlings relatively large, with several sets of true leaves? Have they outgrown their current containers?
• Root Health: Gently tip one of the pots over to check the root system. Are the roots starting to circle the bottom of the pot? If they are heavily root-bound, it’s definitely time to repot.
• Spacing: If you sowed multiple seeds per cell or pot (which is common), are the seedlings crowded together? Are they competing for space and resources?

Timing is Everything: When to Pot On

The timing of potting on is crucial. Here’s what to consider:

• Avoid Overcrowding: Potting on is generally recommended when the seedlings have outgrown their initial containers. If you see signs of overcrowding (like the seedlings being too close together or roots circling the bottom), it’s time to take action.
• Before Planting Out: If you can’t plant your lupins out immediately, potting on provides them with the space they need to continue growing. If you need to wait four weeks before transplanting, potting on is definitely a good idea, because they will continue to grow in that time.
• Weather Conditions: Ideally, repot on a cloudy day or in the evening. This minimizes stress on the seedlings.

The Potting-On Process: A Step-by-Step Guide

Potting on lupin seedlings is a straightforward process:

1. Gather Your Supplies: You’ll need larger pots (about 9-12 cm), fresh potting mix, a trowel or small scoop, and a watering can.
2. Prepare the New Pots: Fill the new pots with fresh potting mix. Make sure the mix is moist but not soggy. A good quality, free-draining compost is essential.
3. Gently Remove the Seedlings: Carefully remove the seedlings from their current containers. If you have multiple seedlings in one pot, gently tease them apart. Be gentle to avoid damaging the roots.
4. Planting: Make a hole in the center of the new pot that’s large enough to accommodate the roots. Place the seedling in the hole, ensuring that the top of the root ball is level with the soil surface. Gently fill in around the roots with potting mix, and lightly firm the soil.
5. Water Thoroughly: Water the newly potted seedlings thoroughly to settle the soil and provide moisture.
6. Provide Care: Place the potted seedlings in a sheltered location with plenty of light. Water them regularly, but avoid overwatering. Allow the soil to dry out slightly between waterings.

Addressing Common Concerns

• Two Seedlings Per Pot: If you sowed two seeds per pot, the seedlings are likely competing for resources. Potting them on individually is the best approach to give them a chance to grow. Gently separate the seedlings when repotting, being careful not to damage the roots.
• Transplant Shock: Seedlings can experience transplant shock after being moved. This is a temporary setback caused by the stress of being moved and the disruption of their roots. You can help reduce transplant shock by:
  • Watering well after potting.
  • Keeping the seedlings in a sheltered location for a few days.
  • Avoiding direct sunlight immediately after potting on.
• Leggy Seedlings: If your seedlings are tall and spindly (leggy), they’re likely not getting enough light. Move them to a brighter location.

Long-Term Lupin Care

Once your lupins are established and you’ve planted them out, here’s what they’ll need to thrive:

• Sunlight: Lupins love full sun. Choose a planting location that receives at least six hours of sunlight per day.
• Soil: They prefer well-drained soil that is slightly acidic to neutral. Amend your soil with compost before planting.
• Watering: Water regularly, especially during dry periods. Avoid overwatering, as this can lead to root rot.
• Deadheading: Deadheading (removing spent flower spikes) encourages more blooms.
• Protection: Lupins can be susceptible to slugs and snails, especially when young. Use appropriate pest control methods as needed.

Final Thoughts: Nurturing Your Lupins

Potting on your lupin seedlings is a vital step in their journey from seed to stunning blooms. By assessing their needs, timing the process correctly, and providing proper care, you’ll be well on your way to enjoying the beauty of these garden favourites. With a little care and attention, your lupins will reward you with their vibrant colours and elegant spires for years to come.