Planting up a container with seedlings

Planting a Container with Seedlings

As well as filling borders and creating a cut flower garden, you can use your seedlings to plant up a pot for an impactful display in a small space. In this lesson, we'll look at how to plant up a container for best results, and what you'll need to get started.

The optimum time to plant is before the plants get too big and before they become potbound. Once this happens, their growth slows down and vigour starts to dwindle. Roots should be just starting to come out of the bottom of the pot but without being potbound.

Choosing plants for a container display

I'm using four plants in this pot, which is just over a foot wide. It's often said that a container should contain plants that perform three contrasting roles.

1. Thriller – a bold or tall standout plant that forms a focal point, often in the middle.
2. Spiller – tumbles over the side of the container to soften edges and give a natural look.
3. Filler – plants that weave through to add body, fill gaps and give the planting a full look.

I'm using:

• 1 x Penstemon 'Twizzle Coral' (perennial) – thriller
• 1 x Phlox (hardy annual) – spiller
• 1 x Antirrhinum 'Madame Butterfly Bronze' (grown as half-hardy annual) – filler
• 3 x Panicum 'Frosted Explosion' (grown as half-hardy annual) – filler grass to give airy texture

Other things you'll need

1. Pot with drainage hole(s): I'm using a terracotta pot with one large hole at the base.

• Make sure there are holes, as this is critical for drainage.
• If the hole is large you can loosely cover it with a crock (curved piece of broken pot or tile) to stop compost or gravel from falling out, but make sure water can still escape freely.

1. Compost: I'm using a mixture of peat-free multipurpose compost and sieved, well-rotted homemade compost.

• Any homemade compost you use needs to be well-rotted so that it's not still in the process of breaking down.

1. Gravel: I put a layer in the bottom of the pot to help with drainage.

How to plant up a pot

1. Put a layer of gravel in the bottom.
2. Fill the pot to about ¾ full with compost, or so that when the plants are placed inside, the top of their compost comes to about an inch below the rim of the pot.
3. Place the plants in the pot. Ensuring everything has some space to fill out, but you can plant things much closer together than you would in a border because it's a temporary scheme.
4. Fill in around the plants with compost.
5. Gently firm the compost with your fingertips, without pressing hard, which will exclude air (roots need oxygen).
6. Water in well and keep watering regularly throughout the summer – I'm watering my pots every day at the moment in June. Try to capture and use rainwater as much as possible.

Plant Directory

Penstemon barbatus 'Twizzle Coral'

Bearded penstemon 'Twizzle Coral'

Semi-evergreen hardy perennial

Plantaginaceae

Phlox drummondii 'Crème Brûlée'

Annual phlox 'Crème Brûlée'

Short-lived perennial grown as half-hardy annual

Polemoniaceae

Antirrhinum majus 'Madame Butterfly Bronze'

Snapdragon 'Madame Butterfly Bronze'

Short-lived perennial, grown as an annual

Plantaginaceae

Panicum capillare 'Frosted Explosion'

Witch grass 'Frosted Explosion'

Half-hardy annual

Poaceae